Although plant growth is primarily limited by the salinity (ECw) level of the irrigation water, the application of water with a sodium imbalance can further reduce yield under certain soil texture conditions. Reductions in water infiltration can occur when irrigation water contains high sodium relative to the calcium and magnesium contents. This condition is termed "sodicity," and results from excessive accumulation of sodium in soil. Sodic water is not the same as saline water. Sodicity causes swelling and dispersion of soil clays, surface crusting and pore plugging. This degraded soil structure condition in turn obstructs infiltration and may increase runoff. Sodicity therefore, causes a decrease in the downward movement of water into and through the soil, and actively growing plants roots may not get adequate water, despite pooling of water on the soil surface after irrigation. The most common measure to assess sodicity in water and soil is called the Sodium Adsorption Ratio (SAR). The SAR defines sodicity in terms of the relative concentration of sodium (Na) compared to the sum of calcium (Ca) and magnesium (Mg) ions in a sample. The SAR assesses the potential for infiltration problems due to a sodium imbalance in irrigation water. The SAR is used to estimate the sodicity hazard of the water, where:

applied Ppm 0.23 lb per acre inch of water

Table 2. Conversion factors for irrigation water quality laboratory reports. Source: Bauder *et*

Irrigation water acre inch 27,150 gallons of water

Abbrev. Meaning

mg/L milligrams per liter meq/L milliequivalents per liter

Ppm parts per million

water. The SAR is used to estimate the sodicity hazard of the water, where:

dS/m deciSiemens per meter

µS/cm microSiemens per centimeter mmho/cm millimhos per centimeter TDS total dissolved solids

Although plant growth is primarily limited by the salinity (ECw) level of the irrigation water, the application of water with a sodium imbalance can further reduce yield under certain soil texture conditions. Reductions in water infiltration can occur when irrigation water contains high sodium relative to the calcium and magnesium contents. This condition is termed "sodicity," and results from excessive accumulation of sodium in soil. Sodic water is not the same as saline water. Sodicity causes swelling and dispersion of soil clays, surface crusting and pore plugging. This degraded soil structure condition in turn obstructs infiltration and may increase runoff. Sodicity therefore, causes a decrease in the downward movement of water into and through the soil, and actively growing plants roots may not get adequate water, despite pooling of water on the soil surface after irrigation. The most common measure to assess sodicity in water and soil is called the Sodium Adsorption Ratio (SAR). The SAR defines sodicity in terms of the relative concentration of sodium (Na) compared to the sum of calcium (Ca) and magnesium (Mg) ions in a sample. The SAR assesses the potential for infiltration problems due to a sodium imbalance in irrigation

By To Obtain

for EC <5 dS/m 640 TDS (mg/L)

for EC >5 dS/m 800 TDS (mg/L)

Component To Convert Multiply

Water salinity hazard ECw (dS/m)

Water salinity hazard ECw (dS/m)

Water NO3N, SO4-S,B

**2.2 Sodium hazard/SAR**

*al*., 2011 Definitions

Water nutrient or TDS mg/L 1.0 ppm

Water salinity hazard 1 dS/m 1.0 1 mmho/cm Water salinity hazard 1 mmho/cm 1,000 1 µmho/cm

$$\text{SAR} = \frac{\text{Na}}{0.5 \text{ (ca} + \text{mg)}} \text{ and all concentrations are in meq/L}$$

SAR is a measure of the tendency of the irrigation water to cause the replacement of calcium (Ca) ions attached to the soil clay minerals with sodium ions (Na). Sodium clays have poor structure and develop permeability problems. The Residual sodium carbonate (RSC) is the measure in milli equivalents per litre (meq/L) of the excess of carbonates (CO3) and bicarbonates (HCO3) over magnesium (Mg) and calcium (Ca). With high RSC (>1.25) there is a tendency for Ca and Mg to precipitate in the soil, thus increasing the proportion of Na and increasing the SAR of the soil solution.

\*Modified from Ayers and Westcot. 1994. Water Quality for Agriculture, Irrigation and Drainage Paper 29, rev. 1, Food and Agriculture Organization of the United Nations, Rome.

Table 3. Guidelines for assessment of sodium hazard of irrigation water based on SAR and ECw2.

#### **2.3 pH and alkalinity**

The acidity or basicity of irrigation water is expressed as pH (< 7.0 acidic; > 7.0 basic). The normal pH for irrigation water ranges from 6.5 to 8.4. High pH's above 8.5 are often caused by high bicarbonate (HCO3-) and carbonate (CO32-) concentrations, known as alkalinity. Calcium and magnesium ions become insoluble due to high carbonates and bicarbonates thereby leaving sodium as the dominant ion in solution. As also described in the sodium hazard section, this alkaline water could intensify the impact of high SAR water on sodic soil conditions. The main use of pH in a water analysis is for detecting an abnormal water. The normal pH range for irrigation water is from 6.5 to 8.4. An abnormal value is a warning that the water needs further evaluation. Irrigation water with a pH outside the normal range may cause a nutritional imbalance or may contain a toxic ion. Low salinity water (ECw < 0.2 dS/m) sometimes has a pH outside the normal range since it has a very low buffering capacity. This should not cause undue alarm other than to alert the user to a possible imbalance of ions and the need to establish the reason for the adverse pH through full laboratory analysis. Such water normally causes few problems for soils or crops but is very corrosive and may rapidly corrode pipelines, sprinklers and control equipment. Any change in the soil pH caused by the water will take place slowly since the soil is strongly buffered and resists change. An adverse pH may need to be corrected, if possible, by the introduction of an amendment into the water, but this will only be practical in a few instances. It may be easier to correct the soil pH problem that may develop rather than try to treat the water.

Effluent Quality Parameters for Safe use in Agriculture 29

Sensitive Moderately Sensitive Moderately Tolerant Tolerant 0.5-0.75 0.76-1.0 1.1-2.0 2.1-4.0 4.1-6.0 Peach Wheat Carrot Lettuce Alfalfa Onion Barley Potato Cabbage Sugar beet Sunflower Cucumber Corn Tomato

Source: Mass (1984) Salt tolerance of plants. CRC Handbook of Plant Science in Agriculture. B.R. Cristie

The sulfate ion is a major contributor to salinity in many of the irrigation waters. As with boron, sulfate in irrigation water has fertility benefits, and most often irrigation water has enough sulfate for maximum production for most crops. Exceptions are sandy fields with <1

Nitrogen in irrigation water (N) is largely a fertility issue, and nitrate-nitrogen (NO3-N) can be a significant N source as it is found in most of the wastewaters throughout the world. The nitrate ion often occurs at higher concentrations than ammonium in irrigation water. Nitrogen is a plant nutrient and stimulates crop growth. Natural soil nitrogen or added fertilizers are the usual sources, but nitrogen in the irrigation water has much the same effect as soil-applied fertilizer nitrogen and an excess will cause problems, just as too much fertilizer would. If excessive quantities are present or applied, production of several commonly grown crops may get disturbed because of over-stimulation of growth, delayed maturity or poor quality. However, these problems can usually be overcome by good fertilizer and irrigation management. The sensitivity of crops varies with the growth stage. High nitrogen levels may be beneficial during early growth stages but may cause yield losses during the later flowering and fruiting stages (Tak et al., 2010). High nitrogen water can be used as a fertilizer early in the season. However, as the nitrogen needs of the crop diminish later in the growing season, the nitrogen applied to the crop must be substantially reduced. For crops irrigated with water containing nitrogen, the rates of nitrogen fertilizer supplied to the crop should be reduced by an amount very nearly equal to that available from the water supply. Regardless of the crop, nitrate should be credited toward the fertilizer rate especially when the concentration exceeds 10 ppm NO3-N (45 ppm NO3¯).

A number of elements are normally present in relatively low concentrations, usually less than a few mg/l, in conventional irrigation waters and are called trace elements. They are not normally included in routine analysis of regular irrigation water, but attention should be paid to them when using sewage effluents, particularly if contamination with industrial wastewater discharges is suspected. These include Aluminium (Al), Beryllium (Be), Cobalt (Co), Fluoride (F), Iron (Fe), Lithium (Li), Manganese (Mn), Molybdenum (Mo), Selenium

Table 4. Boron sensitivity of selected Colorado plants (B concentration, mg/ L\*)

Dry Bean Oats

percent organic matter and <10 ppm SO4-S in irrigation water.

**2.8 Trace elements and heavy metals**

(ed.). CRC Press Inc.

**2.6 Sulfate**

**2.7 Nitrate**

Lime is commonly applied to the soil to correct a low pH and sulphur or other acid material may be used to correct a high pH. Gypsum has little or no effect in controlling an acid soil problem apart from supplying a nutritional source of calcium, but it is effective in reducing a high soil pH (pH greater than 8.5) caused by high exchangeable sodium. The greatest direct hazard of an abnormal pH in water is the impact on irrigation equipment. Equipment will need to be chosen carefully for unusual water.

#### **2.4 Chloride**

Chloride is a common ion in most of the irrigation waters. Although chloride is essential to plants in very low amounts however, it can cause toxicity to sensitive crops at high concentrations. Like sodium, high chloride concentrations cause more problems. The degree of damage depends on the uptake and the crop sensitivity. The permanent, perennial-type crops (tree crops) are more sensitive. Damage often occurs at relatively low ion concentrations for sensitive crops. It is usually first evidenced as marginal leaf burn and interveinal chlorosis. If the accumulation is great enough, reduced yields result. The more tolerant annual crops are not sensitive at low concentrations but almost all crops will be damaged or killed if concentrations are amply high.

#### **2.5 Boron**

Boron, unlike sodium, is an essential element for plant growth (Chloride is also essential but in such small quantities that it is frequently classed non-essential.) Boron is needed in relatively small amounts, however, if present in amounts appreciably greater than needed, it becomes toxic. For some crops, if 0.2 mg/l boron in water is essential, 1 to 2 mg/l may become toxic. Surface water rarely contains enough boron to be toxic but well water or springs occasionally may contain toxic amounts, especially near geothermal areas and earthquake faults. Boron problems originating from the water are probably more frequent than those originating in the soil. Boron toxicity can affect nearly all crops but, like salinity, there is a wide range of tolerance among crops. Boron toxicity symptoms normally show first on older leaves as a yellowing, spotting, or drying of leaf tissue at the tips and edges. Drying and chlorosis often progress towards the centre between the veins (interveinal) as more and more boron accumulates with time. On seriously affected trees, such as almonds and other tree crops which do not show typical leaf symptoms, a gum or exudate on limbs or trunk is often noticeable. Most crop toxicity symptoms occur after boron concentrations in leaf blades exceed 250–300 mg/kg (dry weight) but not all sensitive crops accumulate boron in leaf blades. For example, stone fruits (peaches, plums, almonds, etc.), and pome fruits (apples, pears and others) are easily damaged by boron but they do not accumulate sufficient boron in the leaf tissue for leaf analysis to be a reliable diagnostic test. With these crops, boron excess must be confirmed from soil and water analyses, tree symptoms and growth characteristics.

A wide range of crops were tested for boron tolerance by using sand-culture techniques (Eaton 1944). Previous boron tolerance tables in general use have been based for the most part on these data. These tables reflected boron tolerance at which toxicity symptoms were first observed and, depending on crop, covered one to three seasons of irrigation. The original data from these early experiments, plus data from many other sources, have recently been reviewed (Maas 1984). Table 4 presents this recent revision of the data. It is not based on plant symptoms, but upon a significant loss in yield to be expected if the indicated boron value is exceeded.

Source: Mass (1984) Salt tolerance of plants. CRC Handbook of Plant Science in Agriculture. B.R. Cristie (ed.). CRC Press Inc.

Table 4. Boron sensitivity of selected Colorado plants (B concentration, mg/ L\*)

#### **2.6 Sulfate**

28 Water Quality, Soil and Managing Irrigation of Crops

Lime is commonly applied to the soil to correct a low pH and sulphur or other acid material may be used to correct a high pH. Gypsum has little or no effect in controlling an acid soil problem apart from supplying a nutritional source of calcium, but it is effective in reducing a high soil pH (pH greater than 8.5) caused by high exchangeable sodium. The greatest direct hazard of an abnormal pH in water is the impact on irrigation equipment. Equipment

Chloride is a common ion in most of the irrigation waters. Although chloride is essential to plants in very low amounts however, it can cause toxicity to sensitive crops at high concentrations. Like sodium, high chloride concentrations cause more problems. The degree of damage depends on the uptake and the crop sensitivity. The permanent, perennial-type crops (tree crops) are more sensitive. Damage often occurs at relatively low ion concentrations for sensitive crops. It is usually first evidenced as marginal leaf burn and interveinal chlorosis. If the accumulation is great enough, reduced yields result. The more tolerant annual crops are not sensitive at low concentrations but almost all crops will be

Boron, unlike sodium, is an essential element for plant growth (Chloride is also essential but in such small quantities that it is frequently classed non-essential.) Boron is needed in relatively small amounts, however, if present in amounts appreciably greater than needed, it becomes toxic. For some crops, if 0.2 mg/l boron in water is essential, 1 to 2 mg/l may become toxic. Surface water rarely contains enough boron to be toxic but well water or springs occasionally may contain toxic amounts, especially near geothermal areas and earthquake faults. Boron problems originating from the water are probably more frequent than those originating in the soil. Boron toxicity can affect nearly all crops but, like salinity, there is a wide range of tolerance among crops. Boron toxicity symptoms normally show first on older leaves as a yellowing, spotting, or drying of leaf tissue at the tips and edges. Drying and chlorosis often progress towards the centre between the veins (interveinal) as more and more boron accumulates with time. On seriously affected trees, such as almonds and other tree crops which do not show typical leaf symptoms, a gum or exudate on limbs or trunk is often noticeable. Most crop toxicity symptoms occur after boron concentrations in leaf blades exceed 250–300 mg/kg (dry weight) but not all sensitive crops accumulate boron in leaf blades. For example, stone fruits (peaches, plums, almonds, etc.), and pome fruits (apples, pears and others) are easily damaged by boron but they do not accumulate sufficient boron in the leaf tissue for leaf analysis to be a reliable diagnostic test. With these crops, boron excess must be

confirmed from soil and water analyses, tree symptoms and growth characteristics.

A wide range of crops were tested for boron tolerance by using sand-culture techniques (Eaton 1944). Previous boron tolerance tables in general use have been based for the most part on these data. These tables reflected boron tolerance at which toxicity symptoms were first observed and, depending on crop, covered one to three seasons of irrigation. The original data from these early experiments, plus data from many other sources, have recently been reviewed (Maas 1984). Table 4 presents this recent revision of the data. It is not based on plant symptoms, but upon a significant loss in yield to be expected if the indicated

will need to be chosen carefully for unusual water.

damaged or killed if concentrations are amply high.

**2.4 Chloride**

**2.5 Boron**

boron value is exceeded.

The sulfate ion is a major contributor to salinity in many of the irrigation waters. As with boron, sulfate in irrigation water has fertility benefits, and most often irrigation water has enough sulfate for maximum production for most crops. Exceptions are sandy fields with <1 percent organic matter and <10 ppm SO4-S in irrigation water.

#### **2.7 Nitrate**

Nitrogen in irrigation water (N) is largely a fertility issue, and nitrate-nitrogen (NO3-N) can be a significant N source as it is found in most of the wastewaters throughout the world. The nitrate ion often occurs at higher concentrations than ammonium in irrigation water. Nitrogen is a plant nutrient and stimulates crop growth. Natural soil nitrogen or added fertilizers are the usual sources, but nitrogen in the irrigation water has much the same effect as soil-applied fertilizer nitrogen and an excess will cause problems, just as too much fertilizer would. If excessive quantities are present or applied, production of several commonly grown crops may get disturbed because of over-stimulation of growth, delayed maturity or poor quality. However, these problems can usually be overcome by good fertilizer and irrigation management. The sensitivity of crops varies with the growth stage. High nitrogen levels may be beneficial during early growth stages but may cause yield losses during the later flowering and fruiting stages (Tak et al., 2010). High nitrogen water can be used as a fertilizer early in the season. However, as the nitrogen needs of the crop diminish later in the growing season, the nitrogen applied to the crop must be substantially reduced. For crops irrigated with water containing nitrogen, the rates of nitrogen fertilizer supplied to the crop should be reduced by an amount very nearly equal to that available from the water supply. Regardless of the crop, nitrate should be credited toward the fertilizer rate especially when the concentration exceeds 10 ppm NO3-N (45 ppm NO3¯).

#### **2.8 Trace elements and heavy metals**

A number of elements are normally present in relatively low concentrations, usually less than a few mg/l, in conventional irrigation waters and are called trace elements. They are not normally included in routine analysis of regular irrigation water, but attention should be paid to them when using sewage effluents, particularly if contamination with industrial wastewater discharges is suspected. These include Aluminium (Al), Beryllium (Be), Cobalt (Co), Fluoride (F), Iron (Fe), Lithium (Li), Manganese (Mn), Molybdenum (Mo), Selenium

Effluent Quality Parameters for Safe use in Agriculture 31

water supply, but this alone is not enough; methods to overcome or adapt to them are also needed. The guidelines do not evaluate the effect of unusual or special water constituents sometimes found in wastewater, such as pesticides and organics. However, suggested limits of trace element concentrations or normal irrigation water are given in Table 6. The World Health Organization (WHO) or a local health agency should be consulted for more specific information. Laboratory determinations and calculations needed to use the guidelines are given in Table 7 along with the symbols used. Analytical procedures for the laboratory determinations are given in several publications: USDA Handbook 60 (Richards 1954), Rhoades and Clark 1978, FAO Soils Bulletin 10 (Dewis and Freitas 1970), and Standard Methods for Examination of Waters and Wastewaters (APHA 1980). The method most appropriate for the available equipment, budget and number of samples should be used.

 Guidelines for determination of water quality for irrigation Source FAO, 1985

Boron (B) mg/l <0.7 0.7-3.0 >3.0 Nitrogen (NO3 -N) mg/l <5.0 5.0-30 >30 Bicarbonate (HCO3) me/l <1.5 1.5-8.5 >8.5 pH Normal range 6.5-8.0

Sprinkler irrigation me/l <3.0 >3

Sprinkler irrigation m3/l <3.0 >4.0

ECW ds/m <0.7 0.7-3.0 >3.0

TDS mg/l <450 450-2000` >2000

0-3 >0.7 0.7-0.2 <0.2 3-6 >1.2 1.2-0.3 <0.3 6-12 >1.9 1.9-0.5 <0.5. 12-20 >2.9 2.9-1.3 <1.3 20-40 >5.0 5.0-2.9 <3.0

Degree of restriction on use

moderate Severe

None Slight to

Analytical accuracy within ±5 percent is considered adequate.

Potential irrigation problem Units

Or

SAR and ECW

Sodium (Na)

(Se), Tin (Sn), Titanium (Ti), Tungsten (W) and Vanadium (V). Heavy metals are a special group of trace elements which have been shown to create definite health hazards when taken up by plants. Under this group are included, Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb), Mercury (Hg) and Zinc (Zn). These are called heavy metals because in their metallic form, their densities are greater than 4g/cc. Table 6 gives the insight on the recommended maximum concentration of trace elements in irrigation water.

#### **2.9 Guidelines**

Water quality criteria can never be absolute because soils, management and drainage can influence water suitability. There is, for example a ten—fold range in the salt—tolerance of plants which gives wide scope for utilizing water of different quality. Table 5 (FAO 1985) gives broad guidelines that have been developed for the preliminary evaluation of irrigation water quality. Where a water quality parameter is in the range of increasing problems more detailed investigation is required. For instance, in the range of increasing salinity problems (0.7 to 3.0 dS m-1) more concern is required in the selection of plant species and precautions are needed to minimize salt injury. Where limitations are given the application of appropriate management methods may mean that the waters are still viable. The table thus avoids rigid classification methods which can at times be misleading. They emphasize the long-term influence of water quality on crop production, soil conditions and farm management, and are presented in the same format as in the 1976 edition but are updated to include recent research results. This format is similar to that of the 1974 University of California Committee of Consultant's Water Quality Guidelines which were prepared in cooperation with staff of the United States Salinity Laboratory. The guidelines are practical and have been used successfully in general irrigated agriculture for evaluation of the common constituents in surface water, groundwater, drainage water, sewage effluent and wastewater. A modified set of alternative guidelines can be prepared if actual conditions of use differ greatly from those assumed. Ordinarily, no soil or cropping problems are experienced or recognized when using water with values less than those shown for 'no restriction on use'. With restrictions in the slight to moderate range, gradually increasing care in selection of crop and management alternatives is required if full yield potential is to be achieved. On the other hand, if water is used which equals or exceeds the values shown for severe restrictions, the water user should experience soil and cropping problems or reduced yields, but even with cropping management designed especially to cope with poor quality water, a high level of management skill is essential for acceptable production. If water quality values are found which approach or exceed those given for the severe restriction category, it is recommended that before initiating the use of the water in a large project, a series of pilot farming studies be conducted to determine the economics of the farming and cropping techniques that need to be implemented. Table 5 is a management tool. As with many such interpretative tools in agriculture, it is developed to help users such as water agencies, project planners, agriculturalists, scientists and trained field people to understand better the effect of water quality on soil conditions and crop production. With this understanding, the user should be able to adjust management to utilize poor quality water better. However, the user of Table 5 must guard against drawing unwarranted conclusions based only on the laboratory results and the guideline interpretations as these must be related to field conditions and must be checked, confirmed and tested by field trials or experience. The guidelines are a first step in pointing out the quality limitations of a

(Se), Tin (Sn), Titanium (Ti), Tungsten (W) and Vanadium (V). Heavy metals are a special group of trace elements which have been shown to create definite health hazards when taken up by plants. Under this group are included, Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb), Mercury (Hg) and Zinc (Zn). These are called heavy metals because in their metallic form, their densities are greater than 4g/cc. Table 6 gives the insight on the recommended maximum concentration of trace elements in

Water quality criteria can never be absolute because soils, management and drainage can influence water suitability. There is, for example a ten—fold range in the salt—tolerance of plants which gives wide scope for utilizing water of different quality. Table 5 (FAO 1985) gives broad guidelines that have been developed for the preliminary evaluation of irrigation water quality. Where a water quality parameter is in the range of increasing problems more detailed investigation is required. For instance, in the range of increasing salinity problems (0.7 to 3.0 dS m-1) more concern is required in the selection of plant species and precautions are needed to minimize salt injury. Where limitations are given the application of appropriate management methods may mean that the waters are still viable. The table thus avoids rigid classification methods which can at times be misleading. They emphasize the long-term influence of water quality on crop production, soil conditions and farm management, and are presented in the same format as in the 1976 edition but are updated to include recent research results. This format is similar to that of the 1974 University of California Committee of Consultant's Water Quality Guidelines which were prepared in cooperation with staff of the United States Salinity Laboratory. The guidelines are practical and have been used successfully in general irrigated agriculture for evaluation of the common constituents in surface water, groundwater, drainage water, sewage effluent and wastewater. A modified set of alternative guidelines can be prepared if actual conditions of use differ greatly from those assumed. Ordinarily, no soil or cropping problems are experienced or recognized when using water with values less than those shown for 'no restriction on use'. With restrictions in the slight to moderate range, gradually increasing care in selection of crop and management alternatives is required if full yield potential is to be achieved. On the other hand, if water is used which equals or exceeds the values shown for severe restrictions, the water user should experience soil and cropping problems or reduced yields, but even with cropping management designed especially to cope with poor quality water, a high level of management skill is essential for acceptable production. If water quality values are found which approach or exceed those given for the severe restriction category, it is recommended that before initiating the use of the water in a large project, a series of pilot farming studies be conducted to determine the economics of the farming and cropping techniques that need to be implemented. Table 5 is a management tool. As with many such interpretative tools in agriculture, it is developed to help users such as water agencies, project planners, agriculturalists, scientists and trained field people to understand better the effect of water quality on soil conditions and crop production. With this understanding, the user should be able to adjust management to utilize poor quality water better. However, the user of Table 5 must guard against drawing unwarranted conclusions based only on the laboratory results and the guideline interpretations as these must be related to field conditions and must be checked, confirmed and tested by field trials or experience. The guidelines are a first step in pointing out the quality limitations of a

irrigation water.

**2.9 Guidelines**

water supply, but this alone is not enough; methods to overcome or adapt to them are also needed. The guidelines do not evaluate the effect of unusual or special water constituents sometimes found in wastewater, such as pesticides and organics. However, suggested limits of trace element concentrations or normal irrigation water are given in Table 6. The World Health Organization (WHO) or a local health agency should be consulted for more specific information. Laboratory determinations and calculations needed to use the guidelines are given in Table 7 along with the symbols used. Analytical procedures for the laboratory determinations are given in several publications: USDA Handbook 60 (Richards 1954), Rhoades and Clark 1978, FAO Soils Bulletin 10 (Dewis and Freitas 1970), and Standard Methods for Examination of Waters and Wastewaters (APHA 1980). The method most appropriate for the available equipment, budget and number of samples should be used. Analytical accuracy within ±5 percent is considered adequate.

Table 5. Guidelines for determination of water quality for irrigation Source FAO, 1985

Effluent Quality Parameters for Safe use in Agriculture 33

Total dissolved solids TDS mg/l Electrical conductivity Ecw dS/m1 Temperature T °C Colour/Turbidity NTU/JTU2 Hardness mg equiv. CaCO3/l

Calcium Ca++ me/l3 Magnesium Mg++ me/l Sodium Na+ me/l Carbonate CO3-- me/l Bicarbonate HCO3- me/l Chloride Cl- me/l Sulphate SO4- me/l

Boron B mg/l4 Nitrate-Nitrogen NO3-N mg/l Phosphate Phosphorus PO4-P mg/l Potassium K mg/l Trace metals mg/l Heavy metals mg/l

Table 7. Parameters used in the evaluation of agricultural water quality Source: Kandiah

Guidelines for the safe use of wastewater in agriculture need to maximize public health benefits while allowing for the beneficial use of scarce resources. Achieving this balance in the variety of situations that occur worldwide (especially in settings where there may be no wastewater treatment) can be difficult. Guidelines are needed to be adaptable to the local social, economic, and environmental conditions and should be co-implemented with such other health interventions as hygiene promotion, provision of adequate drinking water and sanitation, and other healthcare measures. The *Hyderabad Declaration on Wastewater Use in Agriculture* recognises these principles and recommends a holistic approach to the management of wastewater use in agriculture. Following a major expert meeting in Stockholm Sweden in 1999, the International Water Association (IWA) on behalf of the

Acidity/Basicity pH

Sodium Absorption Ratio SAR

Type and concentration of anions and cations:

Physical

Chemical

(1990)

**3. Health guidelines**

Parameters Symbol Units

\* The maximum concentration is based on a water application rate which is consistent with good irrigation practices (10000 m3 per hectare per year). If the water application rate greatly exceeds this, the maximum concentrations should be adjusted downward accordingly. No adjustment should be made for application rates less than 10 000 m3 per hectare per year. The values given are for water used on a continuous basis at one site. Source: FAO, 1985

Table 6. Recommended maximum concentrations of trace elements in irrigation water

Remarks

Al(aluminium) 5.0 Can cause non-productivity in acid soils (pH < 5.5), but more

Be (beryllium) 0.10 Toxicity to plants varies widely, ranging from 5 mg/l for kale to 0.5 mg/l for bush beans. Cd (cadmium) 0.01 Toxic to beans, beets and turnips at concentrations as low as 0.1

Co (cobalt) 0.05 Toxic to tomato plants at 0.1 mg/l in nutrient solution. Tends to

its toxicity to plants.

Cr (chromium) 0.10 Not generally recognized as an essential growth element.

Cu (copper) 0.20 Toxic to a number of plants at 0.1 to 1.0 mg/l in nutrient solutions.

Fe (iron) 5.0 Not toxic to plants in aerated soils, but can contribute to soil

Li (lithium) 2.5 Tolerated by most crops up to 5 mg/l; mobile in soil. Toxic to

Ni (nickel) 0.20 Toxic to a number of plants at 0.5 mg/l to 1.0 mg/l; reduced

low concentrations. Ti (titanium) ---- Effectively excluded by plants; specific tolerance unknown. V (vanadium) 0.10 Toxic to many plants at relatively low concentrations. Zn (zinc) 2.0 Toxic to many plants at widely varying concentrations; reduced

Pd (lead) 5.0 Can inhibit plant cell growth at very high concentrations. Se (selenium) 0.02 Toxic to plants at concentrations as low as 0.025 mg/l and toxic

The maximum concentration is based on a water application rate which is consistent with good irrigation practices (10000 m3 per hectare per year). If the water application rate greatly exceeds this, the maximum concentrations should be adjusted downward accordingly. No adjustment should be made for application rates less than 10 000 m3 per hectare per year. The values given are for water used on a

Table 6. Recommended maximum concentrations of trace elements in irrigation water

boron.

F (fluoride) 1.0 Inactivated by neutral and alkaline soils.

grass to less than 0.05 mg/l for rice.

any toxicity. As (arsenic) 0.10 Toxicity to plants varies widely, ranging from 12 mg/l for Sudan

alkaline soils at pH > 7.0 will precipitate the ion and eliminate

mg/l in nutrient solutions. Conservative limits recommended due to its potential for accumulation in plants and soils to

Conservative limits recommended due to lack of knowledge on

acidification and loss of availability of essential phosphorus and molybdenum. Overhead sprinkling may result in unsightly

citrus at low concentrations (<0.075 mg/l). Acts similarly to

Can be toxic to livestock if forage is grown in soils with high

to livestock if forage is grown in soils with relatively high levels of added selenium. An essential element to animals but in very

toxicity at pH > 6.0 and in fine textured or organic soils.

concentrations that may be harmful to humans.

be inactivated by neutral and alkaline soils.

deposits on plants, equipment and buildings.

0.20 Toxic to a number of crops at a few-tenths to a few mg/l, but usually only in acid soils.

0.01 Not toxic to plants at normal concentrations in soil and water.

toxicity at neutral or alkaline pH.

concentrations of available molybdenum.

Element Recommended Maximum

Mn (manganese)

Mo

\*

continuous basis at one site. Source: FAO, 1985

(molybdenum)

Concentration\* (mg/l)

Table 7. Parameters used in the evaluation of agricultural water quality Source: Kandiah (1990)

#### **3. Health guidelines**

Guidelines for the safe use of wastewater in agriculture need to maximize public health benefits while allowing for the beneficial use of scarce resources. Achieving this balance in the variety of situations that occur worldwide (especially in settings where there may be no wastewater treatment) can be difficult. Guidelines are needed to be adaptable to the local social, economic, and environmental conditions and should be co-implemented with such other health interventions as hygiene promotion, provision of adequate drinking water and sanitation, and other healthcare measures. The *Hyderabad Declaration on Wastewater Use in Agriculture* recognises these principles and recommends a holistic approach to the management of wastewater use in agriculture. Following a major expert meeting in Stockholm Sweden in 1999, the International Water Association (IWA) on behalf of the

Effluent Quality Parameters for Safe use in Agriculture 35

Worldwide many different microbial standards for wastewater use in agriculture have been developed. Most guidelines lay heavy emphasis on microbial standards, but it should be

Water quality criteria for the use in agriculture should not be used without considering various interactive factors. Guidelines established by Ayres and Westcott (1976) takes a better approach to water quality evaluation. Improving the overall levels of agronomic and cultural management to improve water use efficiency can offset yield losses due to poor quality water and improve or maintain profitability. Plants respond to osmotic and ion toxicity effects with a gradually declining yield as water quality deteriorates. This enables the farmer either to accept this loss or to determine whether the marginal return to the cost incurred in avoiding salinity or toxicity problems is worthwhile. Because of the wide range of species tolerance to salinity and toxicity the type of crop being grown has a large bearing on these decisions. Occasional irrigations with poor quality water are often more beneficial than no water at all especially in a Mediterranean environment where salt build—up in the soil is prevented by heavy winter rainfall. Developing realistic guidelines for using wastewater in agriculture also involves the establishment of appropriate health-based targets prior to defining appropriate riskmanagement strategies. Establishing appropriate health-based targets primarily involves an assessment of the risks associated with wastewater use in agriculture, using evidence from available studies of epidemiological and microbiological risks, and risk-assessment studies. Considerations of what is an acceptable or tolerable risk are then necessary; these may involve the use of internationally derived estimates of tolerable risk, but these need to be put into the context of actual disease rates in a population related to all the exposures that lead to that disease, including other water- and sanitation-related exposures together with food-related exposure. Positive health impacts resulting from increased food security, improved nutrition, and additional household income should also be considered. Individual countries may therefore set different health targets, based on their own contexts. Strategies for managing health risks to achieve the health targets include wastewater treatment to achieve appropriate microbiological quality guidelines, crop restriction, waste application methods, control of

The author Dr. Hamid Iqbal Tak is thankful to the staff of environmental plant physiology lab for providing necessary support during the course of study and to University Grants

Adriel Ferreira da Fonseca, Uwe Herpin, Alessandra Monteiro de Paula, Reynaldo Luiz

Al-Jaloud, A.A., Hussain, G., Al-Saati, A.J. and Karimulla, S. (1995). Effect of wastewater

Victória1, Adolpho José Melfi. (2007). Agricultural use of treated sewage effluents: agronomic and environmental implications and perspectives for brazil. *Sci. Agric.*

irrigation on mineral composition of corn and sorghum plants in a pot experiment.

recognized that other strategies for managing health risks may also be effective.

**4. Conclusion**

human exposure, chemotherapy, and vaccination.

Commission for providing financial assistance.

*(Piracicaba, Braz.),* 64 (2): 194-209.

*J. Plant Nutr*., 18: 1677-1692.

**5. Acknowledgement**

**6. Refrences**

World Health Organization (WHO) published "*Water Quality: Guidelines, Standards and Health: Assessment of Risk and Risk Management for Water-related Infectious Disease"*. This publication outlines a harmonized framework for the development of guidelines and standards for water-related microbiological hazards (Bartram *et al.,* 2001; Prüss and Havelaar, 2001). The suggested framework involves the assessment of health risks prior to setting health targets; defining basic control approaches, and evaluating the impact of these combined approaches on public health status (Fig. 1). The framework is flexible and allows countries to adjust the guidelines to local circumstances and compare the associated health risks with risks that may result from microbial exposures through drinking water or recreational/occupational water contact (Bartram *et al*., 2001). It is important that health risks from the use of wastewater in agriculture be put into the context of the overall level of gastrointestinal disease within a given population. The regulation of water quality for irrigation is of international importance because trade in agricultural products across regions is growing and products grown with contaminated water may cause health effects at both the local and transboundary levels. Exports of contaminated fresh produce from different geographical regions can facilitate the spread of both known pathogens and strains with new virulence characteristics into areas where such pathogens are not normally found.

Fig. 1. Stockholm Framework for assessment of risk for water-related microbiological hazards (adapted from Bartram et al., 2001).

Effective guidelines for health protection should be: feasible to implement; adaptable to local social, economic, and environmental factors; and include the following elements:

Worldwide many different microbial standards for wastewater use in agriculture have been developed. Most guidelines lay heavy emphasis on microbial standards, but it should be recognized that other strategies for managing health risks may also be effective.

#### **4. Conclusion**

34 Water Quality, Soil and Managing Irrigation of Crops

World Health Organization (WHO) published "*Water Quality: Guidelines, Standards and Health: Assessment of Risk and Risk Management for Water-related Infectious Disease"*. This publication outlines a harmonized framework for the development of guidelines and standards for water-related microbiological hazards (Bartram *et al.,* 2001; Prüss and Havelaar, 2001). The suggested framework involves the assessment of health risks prior to setting health targets; defining basic control approaches, and evaluating the impact of these combined approaches on public health status (Fig. 1). The framework is flexible and allows countries to adjust the guidelines to local circumstances and compare the associated health risks with risks that may result from microbial exposures through drinking water or recreational/occupational water contact (Bartram *et al*., 2001). It is important that health risks from the use of wastewater in agriculture be put into the context of the overall level of gastrointestinal disease within a given population. The regulation of water quality for irrigation is of international importance because trade in agricultural products across regions is growing and products grown with contaminated water may cause health effects at both the local and transboundary levels. Exports of contaminated fresh produce from different geographical regions can facilitate the spread of both known pathogens and strains with new virulence characteristics into areas where such pathogens are not normally found.

Fig. 1. Stockholm Framework for assessment of risk for water-related microbiological

 Guidance for managing risk (including options other than wastewater treatment) Strategies for guideline implementation (including progressive implementation where

Effective guidelines for health protection should be: feasible to implement; adaptable to local social, economic, and environmental factors; and include the following elements:

hazards (adapted from Bartram et al., 2001).

Evidence-based health risk assessment

necessary).

Water quality criteria for the use in agriculture should not be used without considering various interactive factors. Guidelines established by Ayres and Westcott (1976) takes a better approach to water quality evaluation. Improving the overall levels of agronomic and cultural management to improve water use efficiency can offset yield losses due to poor quality water and improve or maintain profitability. Plants respond to osmotic and ion toxicity effects with a gradually declining yield as water quality deteriorates. This enables the farmer either to accept this loss or to determine whether the marginal return to the cost incurred in avoiding salinity or toxicity problems is worthwhile. Because of the wide range of species tolerance to salinity and toxicity the type of crop being grown has a large bearing on these decisions. Occasional irrigations with poor quality water are often more beneficial than no water at all especially in a Mediterranean environment where salt build—up in the soil is prevented by heavy winter rainfall. Developing realistic guidelines for using wastewater in agriculture also involves the establishment of appropriate health-based targets prior to defining appropriate riskmanagement strategies. Establishing appropriate health-based targets primarily involves an assessment of the risks associated with wastewater use in agriculture, using evidence from available studies of epidemiological and microbiological risks, and risk-assessment studies. Considerations of what is an acceptable or tolerable risk are then necessary; these may involve the use of internationally derived estimates of tolerable risk, but these need to be put into the context of actual disease rates in a population related to all the exposures that lead to that disease, including other water- and sanitation-related exposures together with food-related exposure. Positive health impacts resulting from increased food security, improved nutrition, and additional household income should also be considered. Individual countries may therefore set different health targets, based on their own contexts. Strategies for managing health risks to achieve the health targets include wastewater treatment to achieve appropriate microbiological quality guidelines, crop restriction, waste application methods, control of human exposure, chemotherapy, and vaccination.

#### **5. Acknowledgement**

The author Dr. Hamid Iqbal Tak is thankful to the staff of environmental plant physiology lab for providing necessary support during the course of study and to University Grants Commission for providing financial assistance.

#### **6. Refrences**

**3**

*Pakistan*

**Provision of Essential**

Rizwana Jabeen1 and Rafiq Ahmad2

*1,2Department of Botany, University of Karachi*

**Minerals Through Foliar Sprays**

*1Government College for Women, Shahrah-e-Liaquat, Karachi*

Approximately half of the world's land surface is 'perennial desert or dry lands'. These areas can only be made more productive by irrigation. Indiscriminate use of irrigation water without any management has created salinity problem at many places. Consequently, salinity has become a threat to food supply. Although, currently there is enough food for chronically undernourished (Conway, 1997). Growth of human population will increase by 50%, from 6.1 billion in mid – 2001 to 9.3 billion by 2050, it means that crop production must be increased if food security be ensured, especially for those who live on about \$ 1 per day (UN Millennium Declaration, 2000). Therefore, in view an estimates, there is a requirement for raising yield by 20% in Developed Countries and by 60% in Developing Countries (Owen, 2001). Unfortunately, a strong link with salinization throws an immediate question over the sustainability of using irrigation to increase food production and it has been argued elsewhere (Shannon & Noble, 1990; Flowers & Yeo, 1995) that the primary value of increasing the salt tolerance of crops will be to the sustainability of irrigation. In order to achieve this challenge different ways and means must be find out without major increase in the amount of new land under cultivation, which would further threaten forests and biodiversity. In the light of these demographic, agricultural and ecological issues, the threat

Most horticultural crops are glycophytes (Greenway & Munns, 1980) and have evolved under conditions of low soil salinity. The glycophytes cannot absorb, transport and utilize mineral nutrients as efficiently or as effectively under saline as non-saline conditions. Therefore, high concentrations of Na+ and Cl- in the soil solution may depress nutrients – ion activities and produce extreme ratios of Na+/Cl-, Na+/K+ Ca+/Mg+ and Cl-, NO-3. As a result plant becomes susceptible to osmotic specific ion injury as well as to nutritional disorders that may results in reduced yield or quality. Therefore, an alternative strategy for coping with salinity could, therefore, is to attempt to supplementary foliar irrigation of sodium antagonistic minerals where the growth medium is known to be or may become saline at some time during the plant growth cycle. Antagonistic behavior of excessive monovalent cations (especially sodium present in rhizosphere under saline condition) with monovalent and divalent cations of essential mineral creates physiological disorders for

**1. Introduction**

plant growth.

and effects of salinity become even more alarming.

### **Provision of Essential Minerals Through Foliar Sprays**

Rizwana Jabeen1 and Rafiq Ahmad2 *1Government College for Women, Shahrah-e-Liaquat, Karachi 1,2Department of Botany, University of Karachi Pakistan*

#### **1. Introduction**

36 Water Quality, Soil and Managing Irrigation of Crops

APHA. 1980 American Public Health Association - Standard Methods for the Examination of

Asano T. and Tchobanoglous G. (1987) Municipal wastewater treatment and effluent

Ayers, R.S. and Westcot. D.W. (1994). Water Quality for Agriculture, Irrigation and Drainage Paper 29, rev. 1, Food and Agriculture Organization of the United Nations, Rome. Ayres, R.S. and Westcott, D.W. (1976). Water quality for agriculture. F.A.O. Irrigation and

Bartram, J., Fewtrell, L. and Stenström, T.A. (2001) Harmonised assessment of risk and risk

Bauder, T. A., Waskom, R.M., Sutherland, P.L. and Davis, J. G. (2011). Irrigation Water

Bouwer H. and Chaney R.L. (1974) Land treatment of wastewater. *Advances in Agronomy*,

Dewis J. and Freitas F. 1970 Physical and chemical methods of soil and water analysis. FAO

Eaton F.M. (1944). Deficiency, toxicity and accumulation of boron in plants*. J. Agric. Res*.

FAO. (1985) Water quality for agriculture. R.S. Ayers and D.W. Westcot. Irrigation and

Feigin, A., Ravina, I. & Shalhevet, J. (1991). Irrigation with Treated Sewage Effluent.

Feigin, A., Vaisman, I. and Bielorai, H. (1984). Drip irrigation of cotton with treated municipal effluents: II. Nutrient availability in soil. *J. Environ. Qual*., 13: 234-238. Kandiah A. (1990) Water quality management for sustainable agricultural development.

Maas E.V. (1984) Salt tolerance of plants. The Handbook of Plant Science in Agriculture. B.R.

Prüss, A. and Havelaar, A. (2001) The global burden of disease study and applications in

Rhoades J.D. and Clark M. 1978 Sampling procedures and chemical methods in use at the

Richards L.A. (1954). Diagnosis and improvement of saline and alkali soils. USDA Agricultural Handbook No. 60, US Department of Agriculture, Washington DC. 160 p. Tak, H. I, Inam. A and Inam, A. (2010). Effects of urban wastewater on the growth,

Vazquez-Montiel, O., Horan, N.J. and Mara, D.D. (1996). Management of domestic

water, sanitation, and hygiene. In: Fewtrell, L. and Bartram, J. (eds) Water Quality: Guidelines, Standards and Health; Assessment of Risk and Risk Management for Water-related Infectious Disease. International Water Association (IWA) on behalf

United States Salinity Laboratory for Characterizing Salt-affected Soils and Waters.

photosynthesis and yield of chickpea under different levels of nitrogen*. Urban*

http://www.ext.colostate.edu/pubs/crops/00506.html.

Vol. 26. N.C. Brady (ed). Academic Press, New York.

Division, *FAO, Rome.*

Drainage Paper No. 29 F.A.O. Rome.

Soils Bulletin 10. FAO, Rome. 275 p.

Drainage Paper 29 Rev. 1. FAO, Rome. 174 p.

Natural Resources Forum. 14 (1): 22-32.

*Water Journal,* 7(3), 187 — 195.

Christie (ed). CRC Press, Boca Raton, Florida.

of the World Health Organization, London, UK, pp. 43–60.

Memo Report. US Salinity Laboratory, Riverside, California.

wastewater for reuse in irrigation. *Water Sci. Tech*., 33: 355-362.

69:237–277.

Springer-Verlag, Berlin.

Water and Wastewater, 15th Edition. APHA-AWWA-WPCF, Washington DC. 1000 p.

utilization for irrigation. Paper prepared for the Land and Water Development

management for water-related infectious disease: an overview. In: Fewtrell, L. and Bartram, J. (eds.) Water Quality: Guidelines, Standards and Health; Assessment of Risk and Risk Management for Water-related Infectious Disease. International Water Association (IWA) on behalf of the World Health Organization, London, UK, pp. 1–16.

Quality Criteria. Colorado State University. Agriculture Publication No. 0.506

Approximately half of the world's land surface is 'perennial desert or dry lands'. These areas can only be made more productive by irrigation. Indiscriminate use of irrigation water without any management has created salinity problem at many places. Consequently, salinity has become a threat to food supply. Although, currently there is enough food for chronically undernourished (Conway, 1997). Growth of human population will increase by 50%, from 6.1 billion in mid – 2001 to 9.3 billion by 2050, it means that crop production must be increased if food security be ensured, especially for those who live on about \$ 1 per day (UN Millennium Declaration, 2000). Therefore, in view an estimates, there is a requirement for raising yield by 20% in Developed Countries and by 60% in Developing Countries (Owen, 2001). Unfortunately, a strong link with salinization throws an immediate question over the sustainability of using irrigation to increase food production and it has been argued elsewhere (Shannon & Noble, 1990; Flowers & Yeo, 1995) that the primary value of increasing the salt tolerance of crops will be to the sustainability of irrigation. In order to achieve this challenge different ways and means must be find out without major increase in the amount of new land under cultivation, which would further threaten forests and biodiversity. In the light of these demographic, agricultural and ecological issues, the threat and effects of salinity become even more alarming.

Most horticultural crops are glycophytes (Greenway & Munns, 1980) and have evolved under conditions of low soil salinity. The glycophytes cannot absorb, transport and utilize mineral nutrients as efficiently or as effectively under saline as non-saline conditions. Therefore, high concentrations of Na+ and Cl- in the soil solution may depress nutrients – ion activities and produce extreme ratios of Na+/Cl-, Na+/K+ Ca+/Mg+ and Cl-, NO-3. As a result plant becomes susceptible to osmotic specific ion injury as well as to nutritional disorders that may results in reduced yield or quality. Therefore, an alternative strategy for coping with salinity could, therefore, is to attempt to supplementary foliar irrigation of sodium antagonistic minerals where the growth medium is known to be or may become saline at some time during the plant growth cycle. Antagonistic behavior of excessive monovalent cations (especially sodium present in rhizosphere under saline condition) with monovalent and divalent cations of essential mineral creates physiological disorders for plant growth.

Provision of Essential Minerals Through Foliar Sprays 39

and certainly most crop plants, will not grow in high concentrations of salt: only halophytes

Crop species in general require a substantial quantity of water with lower salt contents. Moderately and highly salt tolerant crop species and non-conventional wild plants (including halophytes) can survive and grow on water with relatively higher salt contents. Salts accumulate in the soil will depend upon the irrigation water quality, irrigation management and the adequacy of drainage. If salts become excessive, will result in yield reduction. As water salinity increases, greater care must be taken to leach salts out of the root zone before their accumulation reaches a concentration, which might affect yields. The frequency of leaching depends on water quality and the crop sensitivity to salinity. Salts are present in irrigation water in relatively small but significant amounts. They originate from dissolution or weathering of the rocks and soil, including dissolution of lime, gypsum and other slowly dissolved soil minerals. The suitability of water for irrigation is determined not

The problems that result vary both in kind and degree, and are modified by soil, climate and crop, as well as by the skill and knowledge of the water user. As a result, there is no set limit on water quality; rather, its suitability for use is determined by the conditions of use which affect the accumulation of the water constituents and which may restrict crop yield. The more complex the problem, the more difficult it is to formulate an economical management

The most common effect of salinity on plant growth is of water stress. Some plants will tolerate high levels of salinity while others can tolerate little or no salinity. This is because some are better able to make the needed osmotic adjustments enabling them to extract more water from a saline soil. The osmotic effects of salinity are result of increased sodium ion concentrations at the root – soil water interface that creates lower water potential. It is well documented that salt stress causes removal of water from the cytoplasm into the extra cellular spaces resulting in a reduction of cytosolic and vacuolar volume (Ashraf, 2004; Munns, 2002). Munns & Termaat, (1986) have shown that the earliest response of a nonhalophyte to salinity is that leaves grow more slowly. Although the plants may experience water stress for a short period until they adjust osmotically, water deficit is not the only factor for limited growth, even at relatively high salinities. Growth is reduced as a function of total electrolyte concentration, soil water content and soil matrix effect and is evidenced by reduction in cell division, cell enlargement, cell expansion, cell wall plasticity in the

Ionic toxicity considered responsible for growth inhibitions under excessive saline environment. Salinity reduces plant growth through ionic influences. It has been reported that salinity affects ion activities in solution by changing the ionic strength, by ion-pair formation, and by precipitation (Cramer et al., 1987), resulting in excessive uptake and transport of the salt ions (Na+, Cl– and SO4-2) and/or an inadequate uptake and transport of essential elements, to produce changes in mineral nutrient uptake that affect plant growth and reduce yields and cause crop failure (Bayuelo-Jiménez et al., 2003). Also, significant entry of Na+ or Cl– results in severe growth reduction or death in salt-sensitive or

(by definition) grow in concentrations of sodium chloride higher than about 400 mM.

only by the total amount of salt present but also by the kind of salt.

growing region of roots and leaves (Neumann, 1997).

programme for solution.

**3.2 Osmotic imbalances**

**3.3 Ionic toxicity**

#### **2. Brief history of mineral nutrition**

A brief resume of essential minerals for plant growth is given below in interest to show that their availability of uptake and utilization is adversely affected under excessive salinity (with special reference of sodium) of rhizosphere.

Glimpses of early history for starting research on essential minerals for plant growth appear in literature, which shows that Theophrastus --- a Greek Philosopher performed experiments in crop nutrition during 287-372 B.C. After him along chain of experiment were carried out from different Scientist to know the importance of mineral nutrients for the plant growth.

The question of the nature of the mineral nutrients remained unanswered since the composition of a plant's ashes does not show whether a certain element found is actually necessary for the survival or whether it is merely roughage. The problem was solved when the plant physiologist J.V. Sachs (1832-1897) rediscovered the hydro-culture technique (hydroponics). J.V. Sachs produced the first useable synthetic nutrient solution together with the chemist J. A. Stockhardt. These experiments let Sachs understand the importance of the root hairs for the uptake of solute nutrients. At about the same time, J. A. L. W. Knop (1861) developed the nutrient solution still used very often. The experiments showed that the cations K+, Ca2+, Mg2+ and small amounts of Fe2+ or Fe3+, as well as the anions SO42-, H2PO4- (or H3PO4) and NO3- are essential for the growth and survival of the plants. From the 1860's to the 1940's several other scientists studied plant mineral nutrition.

When in the 20th century the demands for the purity of chemicals grew, it did become apparent that plants need a number of additional elements, identified other minerals needed by plants in much smaller amounts, so-called trace elements like boron, copper, manganese, zinc and molybdenum are necessary for the plant normal nutrition. During this time several plant nutrition scientists also developed nutrient recipes for optimum plant growth, together with (Hoagland, 1919; Arnon & Hoagland 1940).

A most comprehensive review elaborating the methodology for determining essential mineral elements appears in the book of Sand and Water Culture Methods Used in the Study of Plant Nutrition by (Hewitt, 1966). Another book Mineral Nutrition of Plants: Principles and Perspectives by (Epstein, 1971) described fundamental concepts about plant nutrition. Horst Marschner in 1986 published an inclusive book "Mineral Nutrition of Higher plants" and its next edition in 1996 narrating full knowledge about plant essential minerals.

#### **3. Problems faced for uptake of essential minerals by plants at saline soil**

#### **3.1 Salinity**

Plant performance, usually expressed as crop yield, plant biomass, or crop quality, is affected adversely by salinity. Salinity is a major environmental stress and one of the most severe abiotic factors limiting agricultural production, since it alters the availability of water and nutrients. This effect is mostly reported in semi-arid to arid regions due to accumulation of salts at the soil surface where it inhibits the growth and yields of crop plants especially where irrigation is practiced (Greenway & Munns 1980; Tanji, 1990). The physiology of plant responses to salinity and their relation to salinity resistance have been much researched and frequently reviewed in recent years e.g. (Lauchli, 1990; Munns, 1993; & Neumann, 1997.

Salinity has affected, and continues to affect, the land on which crops are, or might be, grown. Although the amount of salt affected land (about 900×106 ha) is imprecisely known its extent is sufficient to pose a threat to agriculture (Flower & Yeo, 1995; Munns, 2002) since most plants,

A brief resume of essential minerals for plant growth is given below in interest to show that their availability of uptake and utilization is adversely affected under excessive salinity

Glimpses of early history for starting research on essential minerals for plant growth appear in literature, which shows that Theophrastus --- a Greek Philosopher performed experiments in crop nutrition during 287-372 B.C. After him along chain of experiment were carried out from

The question of the nature of the mineral nutrients remained unanswered since the composition of a plant's ashes does not show whether a certain element found is actually necessary for the survival or whether it is merely roughage. The problem was solved when the plant physiologist J.V. Sachs (1832-1897) rediscovered the hydro-culture technique (hydroponics). J.V. Sachs produced the first useable synthetic nutrient solution together with the chemist J. A. Stockhardt. These experiments let Sachs understand the importance of the root hairs for the uptake of solute nutrients. At about the same time, J. A. L. W. Knop (1861) developed the nutrient solution still used very often. The experiments showed that the cations K+, Ca2+, Mg2+ and small amounts of Fe2+ or Fe3+, as well as the anions SO42-, H2PO4- (or H3PO4) and NO3- are essential for the growth and survival of the plants. From the

When in the 20th century the demands for the purity of chemicals grew, it did become apparent that plants need a number of additional elements, identified other minerals needed by plants in much smaller amounts, so-called trace elements like boron, copper, manganese, zinc and molybdenum are necessary for the plant normal nutrition. During this time several plant nutrition scientists also developed nutrient recipes for optimum plant growth,

A most comprehensive review elaborating the methodology for determining essential mineral elements appears in the book of Sand and Water Culture Methods Used in the Study of Plant Nutrition by (Hewitt, 1966). Another book Mineral Nutrition of Plants: Principles and Perspectives by (Epstein, 1971) described fundamental concepts about plant nutrition. Horst Marschner in 1986 published an inclusive book "Mineral Nutrition of Higher plants" and its

**3. Problems faced for uptake of essential minerals by plants at saline soil**

Plant performance, usually expressed as crop yield, plant biomass, or crop quality, is affected adversely by salinity. Salinity is a major environmental stress and one of the most severe abiotic factors limiting agricultural production, since it alters the availability of water and nutrients. This effect is mostly reported in semi-arid to arid regions due to accumulation of salts at the soil surface where it inhibits the growth and yields of crop plants especially where irrigation is practiced (Greenway & Munns 1980; Tanji, 1990). The physiology of plant responses to salinity and their relation to salinity resistance have been much researched and frequently reviewed in recent years e.g. (Lauchli, 1990; Munns, 1993; & Neumann, 1997. Salinity has affected, and continues to affect, the land on which crops are, or might be, grown. Although the amount of salt affected land (about 900×106 ha) is imprecisely known its extent is sufficient to pose a threat to agriculture (Flower & Yeo, 1995; Munns, 2002) since most plants,

different Scientist to know the importance of mineral nutrients for the plant growth.

1860's to the 1940's several other scientists studied plant mineral nutrition.

next edition in 1996 narrating full knowledge about plant essential minerals.

together with (Hoagland, 1919; Arnon & Hoagland 1940).

**3.1 Salinity**

**2. Brief history of mineral nutrition**

(with special reference of sodium) of rhizosphere.

and certainly most crop plants, will not grow in high concentrations of salt: only halophytes (by definition) grow in concentrations of sodium chloride higher than about 400 mM.

Crop species in general require a substantial quantity of water with lower salt contents. Moderately and highly salt tolerant crop species and non-conventional wild plants (including halophytes) can survive and grow on water with relatively higher salt contents.

Salts accumulate in the soil will depend upon the irrigation water quality, irrigation management and the adequacy of drainage. If salts become excessive, will result in yield reduction. As water salinity increases, greater care must be taken to leach salts out of the root zone before their accumulation reaches a concentration, which might affect yields. The frequency of leaching depends on water quality and the crop sensitivity to salinity. Salts are present in irrigation water in relatively small but significant amounts. They originate from dissolution or weathering of the rocks and soil, including dissolution of lime, gypsum and other slowly dissolved soil minerals. The suitability of water for irrigation is determined not only by the total amount of salt present but also by the kind of salt.

The problems that result vary both in kind and degree, and are modified by soil, climate and crop, as well as by the skill and knowledge of the water user. As a result, there is no set limit on water quality; rather, its suitability for use is determined by the conditions of use which affect the accumulation of the water constituents and which may restrict crop yield. The more complex the problem, the more difficult it is to formulate an economical management programme for solution.

#### **3.2 Osmotic imbalances**

The most common effect of salinity on plant growth is of water stress. Some plants will tolerate high levels of salinity while others can tolerate little or no salinity. This is because some are better able to make the needed osmotic adjustments enabling them to extract more water from a saline soil. The osmotic effects of salinity are result of increased sodium ion concentrations at the root – soil water interface that creates lower water potential. It is well documented that salt stress causes removal of water from the cytoplasm into the extra cellular spaces resulting in a reduction of cytosolic and vacuolar volume (Ashraf, 2004; Munns, 2002). Munns & Termaat, (1986) have shown that the earliest response of a nonhalophyte to salinity is that leaves grow more slowly. Although the plants may experience water stress for a short period until they adjust osmotically, water deficit is not the only factor for limited growth, even at relatively high salinities. Growth is reduced as a function of total electrolyte concentration, soil water content and soil matrix effect and is evidenced by reduction in cell division, cell enlargement, cell expansion, cell wall plasticity in the growing region of roots and leaves (Neumann, 1997).

#### **3.3 Ionic toxicity**

Ionic toxicity considered responsible for growth inhibitions under excessive saline environment. Salinity reduces plant growth through ionic influences. It has been reported that salinity affects ion activities in solution by changing the ionic strength, by ion-pair formation, and by precipitation (Cramer et al., 1987), resulting in excessive uptake and transport of the salt ions (Na+, Cl– and SO4 -2) and/or an inadequate uptake and transport of essential elements, to produce changes in mineral nutrient uptake that affect plant growth and reduce yields and cause crop failure (Bayuelo-Jiménez et al., 2003). Also, significant entry of Na+ or Cl– results in severe growth reduction or death in salt-sensitive or

Provision of Essential Minerals Through Foliar Sprays 41

An integrated, holistic approach is needed to conserve water and prevent soil salinization and water logging while protecting the environment and ecology. Firstly, source control through the implementation of more efficient irrigation systems and practices should be undertaken to minimize water application and reduce deep percolation. Unavoidable drainage waters should be intercepted, isolated and reused to irrigate a succession of crops of increasing salt tolerance, possibly including eucalyptus and halophyte species, so as to reduce drainage water volumes further and to conserve water and minimize pollution, while producing useful biomass. Conjunctive use of saline groundwater and surface water should also be undertaken to aid in lowering water table elevations, hence to reduce the

To achieve these goals, new technologies and management practices must be developed and implemented. Efficiency of irrigation must be increased by the adoption of appropriate management strategies, systems and practices and through education and training. Some practices can be used to control salinity within the crop root zone, while other practices can be used to control salinity within larger units of management, such as irrigation projects and river basins. Additional practices can be used to protect offsite environment and ecological

There is usually no single way to achieve salinity control in irrigated lands and associated waters. Many different approaches and practices can be combined into satisfactory control systems; the appropriate combination depends upon economic, climatic, social, as well as

The objective of salinity control is to maintain an acceptable crop yield. Management need not necessarily attempt to control salinity at the lowest possible level, but rather to keep it within limits commensurate with sustained productivity crop; soil and irrigation practices can be modified to help achieve these limits. The problem can be managed through

Salt tolerance of a plant may be considered as the ability to germinate, maintain growth and reproduce under persistent or interrupted salt stress. The salt tolerance of plants is a very acute and complex phenomenon, not only because different plants respond to saline conditions in fundamentally different ways, but also because of the great variation in the stress itself. The relative growth of plants in the presence of salinity is termed as their salt tolerance. The ability of plants to tolerate salt is determined by multiple biochemical pathways that facilitate retention and/or acquisition of water, protect chloroplast functions, and maintain ion homeostasis. Essential pathways in this connection are referred those which lead to synthesis of osmotically active metabolites, specific proteins, and certain free radical scavenging enzymes (Parida & Das, 2005). All salts can affect plants growth, but not all inhibit growth within permissible concentration. In addition, salts do not act alone in the soil, but interact in their effects on plants; some of these interactions are simple (e.g. interactions between Na+ and Ca+), whereas some are complex (e.g. Carbonates and their effects via increased soil pH). Among the most common effects of soil salinity is growth inhibition by Na+ and Cl-. For some plants, especially woody perennials (such as citrus and grapevines), Na+ retained in the woody roots and stems and it is the Cl- that accumulates in the shoot and is most damaging to plant often by inhibiting photosynthesis (Flowers, 1988).

**4. Control measures for salinity**

edaphic and hydrogeologic situations.

**4.1 Use of salt tolerant plants**

need for drainage and its disposal, and to conserve water.

systems - including the associated surface and groundwater resources.

Engineering, Reclamation and Saline Agricultural approach.

glycophytic species, at the same time as producing mild toxicity symptoms in salt-tolerant species (Maathuis & Amtmann, 1999). Ion uptake is the cheapest form of osmotic adjustment under soil saline conditions, but it could also lead to problems of decline in leaf function and ionic imbalance and toxicity (Yildirim et al., 2009). In particular, salinity alters uptake and absorption rates of all mineral nutrients resulting in deficiency symptoms. Bonilla et al. (2004) found that most toxic effects of NaCl can be attributed to Na+ toxicity. Excessive accumulation of Na+ can cause a range of ionic and metabolic problems for plants (Hoai et al., 2003). It can be concluded that excessive amounts of any ion (cat or anion) in growth medium can cause toxicity which is species or cultivar specific. However, sodium ion toxicity is more prevalent and more toxic to plants.

#### **3.4 Nutritional imbalance**

Salinity acts like drought on plants, preventing roots from performing their osmotic activity where water and nutrients move from an area of low concentration into an area of high concentration. Therefore, because of the salt levels in the soil, water and nutrients cannot move into the plant roots. Salt tolerance of a plant is affected under low nutrient availability. Accumulation of Na+ and Cl in leaves through the transpiration flow is a general and longterm process taking place in salt-stress plants (Munns & Termaat, 1986). Nutrient uptake and accumulation by plants is often reduced under saline conditions as a result of competitive process between the nutrient and a major salt species. However, this depends on the type of nutrients and composition of soil solution (Grattan & Grieve 1999; Homaee et al., 2002). Although plants selectively absorb potassium over sodium, Na+- induced K+ deficiency can develop on crops under salinity stress by Na+ salt (Maas & Grattan, 1999). In some cases the uptake and translocation of ions such as K+ and Ca+2 are affected by salt stress. In few examples under saline conditions uptake of some mineral elements is known to increase, which can sustain the growth of plants when tissue elements is higher, like Nitrogen (Sweby et al., 1994). Phosphorus (Awad et al., 1990), Potassium (Hawkins and Lewis, 1993), Calcium (Rengel, 1992) and Manganese (Cramer & Nowak, 1992). There might still be cases, when the imbalance of minerals might not be detectable depending upon the localization of the element rather than the total tissue concentration (Cramer, 1997).

Most studies related to plant nutrition and salinity interactions have been conducted in sand or solution cultures. A major difficulty in understanding plant nutrition status as affected by soil salinity is reconciling results obtained in experiments conducted in the field and in solution cultures (Grattan & Grieve 1999). While application of fertilizers could improve plant nutritional status, it may also increase the salinity of soil solution. Being antagonistic to other cations, sodium inhibits their entry in root system; hence plants suffer deficiency of other mineral elements, which are essential for growth. An immediate response of salinity induced water potential imbalance is closure of stomates, which on one hand effects on the carbon fixation in leaves and on the other causes deficiency of same essential minerals with specific reference to monovalent potassium cation required for enzyme activation and membrane transport. Antagonistic effect of excessive sodium could be avoided in root zone if these essential mono and divalent cations are provided through foliar irrigation to plants. In view of Foliar application of soluble salts is being undertaken in present work containing cations of essential mineral elements (which are antagonized by sodium) along with some anions, which are essential for plant growth; its main objective was to investigate the interactive effects of salinity and foliar spray of different nutrients compositions on growth of *Gossypium hirsutum*.

#### **4. Control measures for salinity**

40 Water Quality, Soil and Managing Irrigation of Crops

glycophytic species, at the same time as producing mild toxicity symptoms in salt-tolerant species (Maathuis & Amtmann, 1999). Ion uptake is the cheapest form of osmotic adjustment under soil saline conditions, but it could also lead to problems of decline in leaf function and ionic imbalance and toxicity (Yildirim et al., 2009). In particular, salinity alters uptake and absorption rates of all mineral nutrients resulting in deficiency symptoms. Bonilla et al. (2004) found that most toxic effects of NaCl can be attributed to Na+ toxicity. Excessive accumulation of Na+ can cause a range of ionic and metabolic problems for plants (Hoai et al., 2003). It can be concluded that excessive amounts of any ion (cat or anion) in growth medium can cause toxicity which is species or cultivar specific. However, sodium

Salinity acts like drought on plants, preventing roots from performing their osmotic activity where water and nutrients move from an area of low concentration into an area of high concentration. Therefore, because of the salt levels in the soil, water and nutrients cannot move into the plant roots. Salt tolerance of a plant is affected under low nutrient availability.

term process taking place in salt-stress plants (Munns & Termaat, 1986). Nutrient uptake and accumulation by plants is often reduced under saline conditions as a result of competitive process between the nutrient and a major salt species. However, this depends on the type of nutrients and composition of soil solution (Grattan & Grieve 1999; Homaee et al., 2002). Although plants selectively absorb potassium over sodium, Na+- induced K+ deficiency can develop on crops under salinity stress by Na+ salt (Maas & Grattan, 1999). In some cases the uptake and translocation of ions such as K+ and Ca+2 are affected by salt stress. In few examples under saline conditions uptake of some mineral elements is known to increase, which can sustain the growth of plants when tissue elements is higher, like Nitrogen (Sweby et al., 1994). Phosphorus (Awad et al., 1990), Potassium (Hawkins and Lewis, 1993), Calcium (Rengel, 1992) and Manganese (Cramer & Nowak, 1992). There might still be cases, when the imbalance of minerals might not be detectable depending upon the

localization of the element rather than the total tissue concentration (Cramer, 1997).

Most studies related to plant nutrition and salinity interactions have been conducted in sand or solution cultures. A major difficulty in understanding plant nutrition status as affected by soil salinity is reconciling results obtained in experiments conducted in the field and in solution cultures (Grattan & Grieve 1999). While application of fertilizers could improve plant nutritional status, it may also increase the salinity of soil solution. Being antagonistic to other cations, sodium inhibits their entry in root system; hence plants suffer deficiency of other mineral elements, which are essential for growth. An immediate response of salinity induced water potential imbalance is closure of stomates, which on one hand effects on the carbon fixation in leaves and on the other causes deficiency of same essential minerals with specific reference to monovalent potassium cation required for enzyme activation and membrane transport. Antagonistic effect of excessive sodium could be avoided in root zone if these essential mono and divalent cations are provided through foliar irrigation to plants. In view of Foliar application of soluble salts is being undertaken in present work containing cations of essential mineral elements (which are antagonized by sodium) along with some anions, which are essential for plant growth; its main objective was to investigate the interactive effects of salinity and foliar spray of different nutrients compositions on growth

in leaves through the transpiration flow is a general and long-

ion toxicity is more prevalent and more toxic to plants.

**3.4 Nutritional imbalance**

Accumulation of Na+ and Cl-

of *Gossypium hirsutum*.

An integrated, holistic approach is needed to conserve water and prevent soil salinization and water logging while protecting the environment and ecology. Firstly, source control through the implementation of more efficient irrigation systems and practices should be undertaken to minimize water application and reduce deep percolation. Unavoidable drainage waters should be intercepted, isolated and reused to irrigate a succession of crops of increasing salt tolerance, possibly including eucalyptus and halophyte species, so as to reduce drainage water volumes further and to conserve water and minimize pollution, while producing useful biomass. Conjunctive use of saline groundwater and surface water should also be undertaken to aid in lowering water table elevations, hence to reduce the need for drainage and its disposal, and to conserve water.

To achieve these goals, new technologies and management practices must be developed and implemented. Efficiency of irrigation must be increased by the adoption of appropriate management strategies, systems and practices and through education and training. Some practices can be used to control salinity within the crop root zone, while other practices can be used to control salinity within larger units of management, such as irrigation projects and river basins. Additional practices can be used to protect offsite environment and ecological systems - including the associated surface and groundwater resources.

There is usually no single way to achieve salinity control in irrigated lands and associated waters. Many different approaches and practices can be combined into satisfactory control systems; the appropriate combination depends upon economic, climatic, social, as well as edaphic and hydrogeologic situations.

The objective of salinity control is to maintain an acceptable crop yield. Management need not necessarily attempt to control salinity at the lowest possible level, but rather to keep it within limits commensurate with sustained productivity crop; soil and irrigation practices can be modified to help achieve these limits. The problem can be managed through Engineering, Reclamation and Saline Agricultural approach.

#### **4.1 Use of salt tolerant plants**

Salt tolerance of a plant may be considered as the ability to germinate, maintain growth and reproduce under persistent or interrupted salt stress. The salt tolerance of plants is a very acute and complex phenomenon, not only because different plants respond to saline conditions in fundamentally different ways, but also because of the great variation in the stress itself. The relative growth of plants in the presence of salinity is termed as their salt tolerance. The ability of plants to tolerate salt is determined by multiple biochemical pathways that facilitate retention and/or acquisition of water, protect chloroplast functions, and maintain ion homeostasis. Essential pathways in this connection are referred those which lead to synthesis of osmotically active metabolites, specific proteins, and certain free radical scavenging enzymes (Parida & Das, 2005). All salts can affect plants growth, but not all inhibit growth within permissible concentration. In addition, salts do not act alone in the soil, but interact in their effects on plants; some of these interactions are simple (e.g. interactions between Na+ and Ca+), whereas some are complex (e.g. Carbonates and their effects via increased soil pH). Among the most common effects of soil salinity is growth inhibition by Na+ and Cl-. For some plants, especially woody perennials (such as citrus and grapevines), Na+ retained in the woody roots and stems and it is the Cl- that accumulates in the shoot and is most damaging to plant often by inhibiting photosynthesis (Flowers, 1988).

Provision of Essential Minerals Through Foliar Sprays 43

absorption include relative humidity, temperature, pH of the nutrient solution, age of leaf, concentration of the nutrient solution, difference in the nutrient compounds (formulations), use of surfactants and addition of non-nutrient facilitating or carriers-

The efficiency with which foliar applied macronutrients are utilized depends on the mobility of the specific nutrient throughout the entire plant, mobility comprising long distance transport especially phloem transport as well as the symplastic transport. Potassium and nitrogen are examples of nutrients showing high mobility and when taken up by leaves they can be rapidly distributed throughout the entire plant. Calcium and sulfur show a low mobility and Ca2+ taken up by leaves cannot be transported to younger tissues or fruits where it may be required. Most nutrients will move freely in the water stream but the movement of many is restricted in the phloem, hence leaf applications do not meet the

Foliar application of potassium is an efficient method of potassium supply to plants to avoid interaction both antagonistic and synergistic with essential major secondary and micronutrients (Dibb & Thompson, 1985). Foliar K+ may be a supplemental nutrient management practice when conditions reduce plant K+ uptake from soil, therefore, foliar application of potassium may be possible management tool to alleviate reduced yields caused by K+ deficiency under saline irrigation. Foliar spray did not only increase the crop yields but also reduce the quantities of fertilizer applied through soil. Islam et al., (2003) used 0.1% KNO3 as foliar spray on jute plant leaves and obtained good results whereas, 250 ppm of KNO3 produce promising results in *Lagenaria siceraria* , (Ahmad & Jabeen, 2005). Similarly, foliar spray of nitrogen also provides best platform to enhance the plant growth when growing in saline strata. Foliar application of nitrogen results in increased grain protein content and bread making quality of wheat when applied at or after anthesis (Gooding & Davies, 1992). Rajput et al., (1995) concluded that foliar application increased heading, maturity, grain and biological yield and gain highest return. Due to high importance of foliar fertilizer and the initial role of nitrogen, in the present study KNO3 was

Role of essential mineral element required in traces for growth and development of plants is known since long in literature (Hewitt, 1966). Small amount of Cu, Zn, B, Fe, Mo, and Mn are essential for growth and quality of the crop because they control most of the physiological activities of the crop by interrupting the level of chlorophyll content in leaves, which ultimately influence the photosynthetic activity of the plant (Kanwar & Randhawa, 1967). Jamro et al., (2002), showed that the effect of foliar application of micronutrients significantly increased the cane length at lowest rates of zinc and copper (1.5 kg and 2.5 kg /ha), produced highest cane length of 145.40 cm and 144.93 cm, respectively, whereas, the

Gregoriou et al., (1983) found that the quickest and most successful treatment of trees suffering from iron chlorosis on calcareous soils was obtained by incorporating Sequestrene 138 Fe - EDDHA in the soil. Kassab (2005) indicated that foliar spray of zinc, manganese and

selected which can provide both K and N sources to the plant.

lowest cane length of 113.07 cm was recorded in untreated plants.

**4.2.2 Foliar spray of micronutrients**

mediated agents (Gary & Grigg, 1999).

**4.2.1 Foliar spray of macronutrients**

requirements of deficient trees.

However, for many plants (such as Germinaceous crops), Na+ is the primary case of ionspecific damage (Tester & Davenport, 2003). It attracted the attention of many investigators and practical agricultural workers because of the need to increase yields on saline soil and to develop and utilize new saline areas. Plant species vary in how well they tolerate saltaffected soils. Many lists of salt tolerant cultivars of important crops and those grown for forage, fodder, wood or others economical purposes are available in literature , (Ahmad, R. & Ismail, S. 1993; Francois, L.E., 1994; Maas, E.V., 1996; Marcar, N.E. et al., 1999; Ahmad, R., & Chang, M.H. 2000). Depending upon prevailing range of saline soil or saline irrigation water( being used in irrigation) edaphic and environmental factors one can select a plant for providing economically feasible yield under saline prevailing adverse condition.

#### **4.2 Mineral nutrition through foliar spray**

The following information has been cited out of some important reviews related to foliar application of mineral nutrients, which have appeared in literature towards the end of the last century, beginning of the present century since they provide precise knowledge on the subject. Foliar fertilization is an effective method of providing a steady flow of nutrients, in combination with some traditional types of root-uptake fertilizers, to achieve better control of nutrients. Foliar irrigation is widely used to supply specific nutrients to many crops growing under saline environment. Foliar application of nutrients is partially overcoming the negative effect of stress condition influencing root growth and absorption capacity (Salama et al., 1996; El-Flouly & Abou El- Nour, 1998). In this respect, (El-Flouly & El-Sayad, 1997) stated that foliar fertilization of both macro and micronutrient is practiced whenever, nutrients uptake through the root system is restricted due to salt stress. The advantages of foliar spray compared to soil fertilization include: immediate response, convenience of combination spray and comparatively low cost. On the other hand foliar spray have some disadvantages, the main disadvantage is these must be repeatedly applied because of the constant loss of leaf blades to mowing. Other includes, the response is only temporary, only very low doses can be applied and there are limitations due to foliar toxicity. When nutrients are applied directly to the foliage, they must penetrate three barriers: i) The waxy cuticle covering on the epidermal cell, ii) The cell wall of the epidermal cell and iii) The plasma membrane of the epidermal cells. Morphology and organization of leaf tissue is such that it accommodates the uptake of gaseous plant nutrients, whilst that of roots the uptake of water-soluble solutes. These water-soluble plant nutrients are mainly supplied with fertilizers. Only in exceptional cases where nutrients are strongly fixed by soils or where aerial nutrient requirement of a crop is higher than the root uptake rates, foliar application can be adopted as a routine fertilization measure.

Similarly, for maximum stomatal entry, nutrient sprays must be applied when the stomata are open, early morning applications are the best. Also, there is less evaporation during the early morning thus giving a better chance for maximum uptake by leaves. Timing is keeping this point in mind spray so did both in regard to time of the season and time of the day a critical factor in foliar spray. High relative humidity during the time of application will also enhance uptake by minimizing evaporation. Foliar sprays may be effective only during "critical stages" of plants growth cycle and must be applied during or shortly before the critical period to be effective. Since immature foliage does not have well-developed cuticular layer, application of nutrient sprays when there is a significant amount of young foliage present will enhance cuticular entry. Factors that affect foliar absorption include relative humidity, temperature, pH of the nutrient solution, age of leaf, concentration of the nutrient solution, difference in the nutrient compounds (formulations), use of surfactants and addition of non-nutrient facilitating or carriersmediated agents (Gary & Grigg, 1999).

#### **4.2.1 Foliar spray of macronutrients**

42 Water Quality, Soil and Managing Irrigation of Crops

However, for many plants (such as Germinaceous crops), Na+ is the primary case of ionspecific damage (Tester & Davenport, 2003). It attracted the attention of many investigators and practical agricultural workers because of the need to increase yields on saline soil and to develop and utilize new saline areas. Plant species vary in how well they tolerate saltaffected soils. Many lists of salt tolerant cultivars of important crops and those grown for forage, fodder, wood or others economical purposes are available in literature , (Ahmad, R. & Ismail, S. 1993; Francois, L.E., 1994; Maas, E.V., 1996; Marcar, N.E. et al., 1999; Ahmad, R., & Chang, M.H. 2000). Depending upon prevailing range of saline soil or saline irrigation water( being used in irrigation) edaphic and environmental factors one can select a plant for

The following information has been cited out of some important reviews related to foliar application of mineral nutrients, which have appeared in literature towards the end of the last century, beginning of the present century since they provide precise knowledge on the subject. Foliar fertilization is an effective method of providing a steady flow of nutrients, in combination with some traditional types of root-uptake fertilizers, to achieve better control of nutrients. Foliar irrigation is widely used to supply specific nutrients to many crops growing under saline environment. Foliar application of nutrients is partially overcoming the negative effect of stress condition influencing root growth and absorption capacity (Salama et al., 1996; El-Flouly & Abou El- Nour, 1998). In this respect, (El-Flouly & El-Sayad, 1997) stated that foliar fertilization of both macro and micronutrient is practiced whenever, nutrients uptake through the root system is restricted due to salt stress. The advantages of foliar spray compared to soil fertilization include: immediate response, convenience of combination spray and comparatively low cost. On the other hand foliar spray have some disadvantages, the main disadvantage is these must be repeatedly applied because of the constant loss of leaf blades to mowing. Other includes, the response is only temporary, only very low doses can be applied and there are limitations due to foliar toxicity. When nutrients are applied directly to the foliage, they must penetrate three barriers: i) The waxy cuticle covering on the epidermal cell, ii) The cell wall of the epidermal cell and iii) The plasma membrane of the epidermal cells. Morphology and organization of leaf tissue is such that it accommodates the uptake of gaseous plant nutrients, whilst that of roots the uptake of water-soluble solutes. These water-soluble plant nutrients are mainly supplied with fertilizers. Only in exceptional cases where nutrients are strongly fixed by soils or where aerial nutrient requirement of a crop is higher than the root uptake rates, foliar application

Similarly, for maximum stomatal entry, nutrient sprays must be applied when the stomata are open, early morning applications are the best. Also, there is less evaporation during the early morning thus giving a better chance for maximum uptake by leaves. Timing is keeping this point in mind spray so did both in regard to time of the season and time of the day a critical factor in foliar spray. High relative humidity during the time of application will also enhance uptake by minimizing evaporation. Foliar sprays may be effective only during "critical stages" of plants growth cycle and must be applied during or shortly before the critical period to be effective. Since immature foliage does not have well-developed cuticular layer, application of nutrient sprays when there is a significant amount of young foliage present will enhance cuticular entry. Factors that affect foliar

providing economically feasible yield under saline prevailing adverse condition.

**4.2 Mineral nutrition through foliar spray**

can be adopted as a routine fertilization measure.

The efficiency with which foliar applied macronutrients are utilized depends on the mobility of the specific nutrient throughout the entire plant, mobility comprising long distance transport especially phloem transport as well as the symplastic transport. Potassium and nitrogen are examples of nutrients showing high mobility and when taken up by leaves they can be rapidly distributed throughout the entire plant. Calcium and sulfur show a low mobility and Ca2+ taken up by leaves cannot be transported to younger tissues or fruits where it may be required. Most nutrients will move freely in the water stream but the movement of many is restricted in the phloem, hence leaf applications do not meet the requirements of deficient trees.

Foliar application of potassium is an efficient method of potassium supply to plants to avoid interaction both antagonistic and synergistic with essential major secondary and micronutrients (Dibb & Thompson, 1985). Foliar K+ may be a supplemental nutrient management practice when conditions reduce plant K+ uptake from soil, therefore, foliar application of potassium may be possible management tool to alleviate reduced yields caused by K+ deficiency under saline irrigation. Foliar spray did not only increase the crop yields but also reduce the quantities of fertilizer applied through soil. Islam et al., (2003) used 0.1% KNO3 as foliar spray on jute plant leaves and obtained good results whereas, 250 ppm of KNO3 produce promising results in *Lagenaria siceraria* , (Ahmad & Jabeen, 2005).

Similarly, foliar spray of nitrogen also provides best platform to enhance the plant growth when growing in saline strata. Foliar application of nitrogen results in increased grain protein content and bread making quality of wheat when applied at or after anthesis (Gooding & Davies, 1992). Rajput et al., (1995) concluded that foliar application increased heading, maturity, grain and biological yield and gain highest return. Due to high importance of foliar fertilizer and the initial role of nitrogen, in the present study KNO3 was selected which can provide both K and N sources to the plant.

#### **4.2.2 Foliar spray of micronutrients**

Role of essential mineral element required in traces for growth and development of plants is known since long in literature (Hewitt, 1966). Small amount of Cu, Zn, B, Fe, Mo, and Mn are essential for growth and quality of the crop because they control most of the physiological activities of the crop by interrupting the level of chlorophyll content in leaves, which ultimately influence the photosynthetic activity of the plant (Kanwar & Randhawa, 1967).

Jamro et al., (2002), showed that the effect of foliar application of micronutrients significantly increased the cane length at lowest rates of zinc and copper (1.5 kg and 2.5 kg /ha), produced highest cane length of 145.40 cm and 144.93 cm, respectively, whereas, the lowest cane length of 113.07 cm was recorded in untreated plants.

Gregoriou et al., (1983) found that the quickest and most successful treatment of trees suffering from iron chlorosis on calcareous soils was obtained by incorporating Sequestrene 138 Fe - EDDHA in the soil. Kassab (2005) indicated that foliar spray of zinc, manganese and

Provision of Essential Minerals Through Foliar Sprays 45

capable of retaining 3 liter of water at saturation. Any additional amount of water easily leaches out from the drainage outlet. The practice of over irrigation avoids salt accumulation

Experiment was divided into 12 sets, viz., 1. Non-spray 2. Foliar spray with water 3. Foliar spray with Fe-EDTA (5-ppm) 4. Foliar spray with MnCl2 (5-ppm) 5. Foliar spray with MoO3 (5-ppm) 6. Foliar spray with KNO3 (500-ppm) 7. Foliar spray with KCl 500-ppm) 8. Foliar spray with Urea (1000-ppm) 9. Foliar spray with KNO3 (500-ppm) + Fe-EDTA (5-ppm) 10. Foliar spray with KNO3 (500-ppm) + MnCl2 (5-ppm) 11. Foliar spray with KNO3 (500-ppm) + MoO3 (5-ppm) 12. Foliar spray with KNO3 (500ppm) + Fe-EDTA (5-ppm) + MnCl2 (5-ppm) +MoO3 (5-ppm). Out of a total 180 pots used in present experiment 15 were used in each set, exposed to three different irrigation regimes given to 5 pots under each treatment viz., i) Nonsaline water (E.Ciw: 0.6 dS/m), ii) 0.4% sea-salt solution (E.Ciw :6.2 dS/m) and iii) 0.8%:

The seeds of *Cotton* variety CIM 496 were used for the current investigations. The seeds were delinted with concentrated H2SO4 for one minute to remove the fiber and immediately washed with running water. The seeds were then surface sterilized with 0.1% HgCl2 for 5 minutes. Five seeds were sown in each plastic pot irrigated with non- saline water. Irrigation with gradually increasing concentrations of sea- salt(S.S) in irrigation water was started in plants at five leaf stages (including cotyledonary leaves) and continued till it reached to the salinity levels of 6.2 and 10.8 dS/m. Pot was irrigated with 3-litre tap water/ salt solution twice a week. Three plants were kept in each pot. Cow dung manure was added in the soil at 9:1 ratio to plastic pots. Whereas NPK (1:2:1) was given in three split dozes. Insecticide and fungicide was used whenever needed. Spray medium was containing 10 ppm of liquid soap as a surfactant. Foliar spray was started at five leaf stage, and followed by at just beginning flowering, and intermediate fruiting stage, plants were completely sprayed with

Complete data on growth of various vegetative parameters i.e. plant height (cm) ,number of leaves and monopodial and sympodial branches, total leaf area, fresh and dry biomass was taken and reported in PhD Thesis (Jabeen, 2009),but due to limitations in number of printed pages only the data on fresh and dry biomass is presented in this chapter. Whereas reproductive parameters is presented in terms of number of squares, flower and balls/ plant, seed and lint weight; seed number per plant, seed cotton yield and lint/ seed ratio was recorded at termination of experiment. Fiber characteristics are reported in PhD Thesis

Samples of leaf and stem, were taken at grand period of growth, and were dried separately overnight in oven at 700C for the analysis of Na+ and K+ (A.O.A.C., 1984). Concentration of

Leaves samples were collected at grand period of growth, from 3rd /4th node below the apex for biochemical analysis. i) Chlorophyll was extracted from the leaves in 80%acetone and measured at 663 nm and 645 nm in a Spectrophotometer as outlined by Machlaclam & Zalik, (1963). ii) A total Soluble Carbohydrates content was measured in an aqueous extract of leaf sample according to Ciha & Brun, (1978). Extraction was done in extraction solution (glacial acetic acid: methanol: water, 1:4:5) and optical density was recorded at 490 nm. iii) Protein was estimated by Hartree (1972). Extraction was done in 5% Trichloroacetic acid (TCA) and

Na+ and K+ cations in samples was measured using a Petracourt PFP.1 Photometer.

estimated after color reaction with Folin Ciocalteu's reagent at 650 nm.

in the rhizosphere.

(Jabeen, 2009).

sea-salt solution (E.Ciw: 10.8 dS/m).

300 ml/plant of respective spray nutrient solution.

iron significantly increased growth parameter yield and its components of mung bean plants. In addition, spraying salinity stressed plants with micronutrients can reduce the undesirable effect of salinity through improving growth and nutrient status of plants as well. Micronutrient requirements can generally be better met by foliar application than requirements of macronutrients because in absolute terms higher quantities of macronutrients are needed. Abou El-Nour (2002) reported that plants irrigated with 5.6 dS/m irrigation water and sprayed with supplementary micronutrients foliar spray with an EDTA micronutrient compound contained 2.8% Fe + 2.8% Mn + 2.8% Zn + 14% N applied to maize showed significant increment in root dry weight as compared to control, where the increment reached to 19%.

#### **4.2.3 Preparation of spray medium**

Recipe of spray medium is also important in which surfactant /adjuvant are mixed with desired minerals to spread liquid on the surface of the leaf and let it stay there for some time for stomatal absorption (Mengel & Kirkby, 1987). Surfactants (surface active agents) are a type of substances designed to improve the dispersing/emulsifying, absorbing spreading, sticking and / penetrating properties of the spray mixture. Pure water will stand as a droplet with a small area of contact with the waxy leaf surface. Water droplet containing a surfactant will spread in a thin layer over a waxy leaf surface. Surfactant lowers the contact angle of spray droplets on the leaves thus enhancing absorption.

It is commonly believed that the optimal pH values of spray solutions for the maximum uptake of most mineral nutrients are within the range of 3.0-5.5 (Kannan, 1980). Acidic foliar sprays can penetrate leaf surfaces more effectively, but it is possible for a negative effect to occur when too much acidity is present. Each type of organic acid has its own pH disassociation range with the mineral as the pH drops (increased acidity). Blanpied (1979) reported that maximum Ca+2 absorption by apple leaves are at pH 3.3 - 5.2. Reed & Tukey (1978) found that maximum phosphorus absorption by Chrysanthemum (*Dendranthema gradiflora*) leaves was at pH 3-6 for Na-Phosphate and pH 7-10 for K-phosphate. Howard et. al., (2000) sprayed *Cotton* with buffer solutions of pH 4 and 6 containing boric acid potassium nitrate separately or in mixture. The highest yield was found when buffer solution of pH 4 was sprayed containing both the above-mentioned chemicals.

#### **5. Materials and methods**

Keeping in view that broad leave plants will have better chance of retaining minerals given through foliar spray medium, commercially important plant *Gossypium hirsutum* belonging to family Malvaceae and grown for lint and oil was selected for present work. Plants were grown with saline water irrigation at sand and foliar application of some sodium antagonistic essential minerals was practiced at different stages of growth. The cotton seeds were obtained from Central Cotton Institute of Multan, Pakistan.

Experiments on growth of *Gossypium hirsutum* was conducted at Biosaline Nursery, Department of Botany (University of Karachi) in large size plastic pots using various combinations of nutrients in foliar spray medium. Some essential trace elements were included which is being di and trivalent show antagonism with monovalent Na+. They were given with K+, which is used as growth promoter for plants raised under saline condition. The pots were filled with 18 kg of costal sand each, having basal outlet for drainage and

iron significantly increased growth parameter yield and its components of mung bean plants. In addition, spraying salinity stressed plants with micronutrients can reduce the undesirable effect of salinity through improving growth and nutrient status of plants as well. Micronutrient requirements can generally be better met by foliar application than requirements of macronutrients because in absolute terms higher quantities of macronutrients are needed. Abou El-Nour (2002) reported that plants irrigated with 5.6 dS/m irrigation water and sprayed with supplementary micronutrients foliar spray with an EDTA micronutrient compound contained 2.8% Fe + 2.8% Mn + 2.8% Zn + 14% N applied to maize showed significant increment in root dry weight as compared to control, where the

Recipe of spray medium is also important in which surfactant /adjuvant are mixed with desired minerals to spread liquid on the surface of the leaf and let it stay there for some time for stomatal absorption (Mengel & Kirkby, 1987). Surfactants (surface active agents) are a type of substances designed to improve the dispersing/emulsifying, absorbing spreading, sticking and / penetrating properties of the spray mixture. Pure water will stand as a droplet with a small area of contact with the waxy leaf surface. Water droplet containing a surfactant will spread in a thin layer over a waxy leaf surface. Surfactant lowers the contact

It is commonly believed that the optimal pH values of spray solutions for the maximum uptake of most mineral nutrients are within the range of 3.0-5.5 (Kannan, 1980). Acidic foliar sprays can penetrate leaf surfaces more effectively, but it is possible for a negative effect to occur when too much acidity is present. Each type of organic acid has its own pH disassociation range with the mineral as the pH drops (increased acidity). Blanpied (1979) reported that maximum Ca+2 absorption by apple leaves are at pH 3.3 - 5.2. Reed & Tukey (1978) found that maximum phosphorus absorption by Chrysanthemum (*Dendranthema gradiflora*) leaves was at pH 3-6 for Na-Phosphate and pH 7-10 for K-phosphate. Howard et. al., (2000) sprayed *Cotton* with buffer solutions of pH 4 and 6 containing boric acid potassium nitrate separately or in mixture. The highest yield was found when buffer

Keeping in view that broad leave plants will have better chance of retaining minerals given through foliar spray medium, commercially important plant *Gossypium hirsutum* belonging to family Malvaceae and grown for lint and oil was selected for present work. Plants were grown with saline water irrigation at sand and foliar application of some sodium antagonistic essential minerals was practiced at different stages of growth. The cotton seeds

Experiments on growth of *Gossypium hirsutum* was conducted at Biosaline Nursery, Department of Botany (University of Karachi) in large size plastic pots using various combinations of nutrients in foliar spray medium. Some essential trace elements were included which is being di and trivalent show antagonism with monovalent Na+. They were given with K+, which is used as growth promoter for plants raised under saline condition. The pots were filled with 18 kg of costal sand each, having basal outlet for drainage and

solution of pH 4 was sprayed containing both the above-mentioned chemicals.

angle of spray droplets on the leaves thus enhancing absorption.

were obtained from Central Cotton Institute of Multan, Pakistan.

increment reached to 19%.

**5. Materials and methods**

**4.2.3 Preparation of spray medium**

capable of retaining 3 liter of water at saturation. Any additional amount of water easily leaches out from the drainage outlet. The practice of over irrigation avoids salt accumulation in the rhizosphere.

Experiment was divided into 12 sets, viz., 1. Non-spray 2. Foliar spray with water 3. Foliar spray with Fe-EDTA (5-ppm) 4. Foliar spray with MnCl2 (5-ppm) 5. Foliar spray with MoO3 (5-ppm) 6. Foliar spray with KNO3 (500-ppm) 7. Foliar spray with KCl 500-ppm) 8. Foliar spray with Urea (1000-ppm) 9. Foliar spray with KNO3 (500-ppm) + Fe-EDTA (5-ppm) 10. Foliar spray with KNO3 (500-ppm) + MnCl2 (5-ppm) 11. Foliar spray with KNO3 (500-ppm) + MoO3 (5-ppm) 12. Foliar spray with KNO3 (500ppm) + Fe-EDTA (5-ppm) + MnCl2 (5-ppm) +MoO3 (5-ppm). Out of a total 180 pots used in present experiment 15 were used in each set, exposed to three different irrigation regimes given to 5 pots under each treatment viz., i) Nonsaline water (E.Ciw: 0.6 dS/m), ii) 0.4% sea-salt solution (E.Ciw :6.2 dS/m) and iii) 0.8%: sea-salt solution (E.Ciw: 10.8 dS/m).

The seeds of *Cotton* variety CIM 496 were used for the current investigations. The seeds were delinted with concentrated H2SO4 for one minute to remove the fiber and immediately washed with running water. The seeds were then surface sterilized with 0.1% HgCl2 for 5 minutes. Five seeds were sown in each plastic pot irrigated with non- saline water. Irrigation with gradually increasing concentrations of sea- salt(S.S) in irrigation water was started in plants at five leaf stages (including cotyledonary leaves) and continued till it reached to the salinity levels of 6.2 and 10.8 dS/m. Pot was irrigated with 3-litre tap water/ salt solution twice a week. Three plants were kept in each pot. Cow dung manure was added in the soil at 9:1 ratio to plastic pots. Whereas NPK (1:2:1) was given in three split dozes. Insecticide and fungicide was used whenever needed. Spray medium was containing 10 ppm of liquid soap as a surfactant. Foliar spray was started at five leaf stage, and followed by at just beginning flowering, and intermediate fruiting stage, plants were completely sprayed with 300 ml/plant of respective spray nutrient solution.

Complete data on growth of various vegetative parameters i.e. plant height (cm) ,number of leaves and monopodial and sympodial branches, total leaf area, fresh and dry biomass was taken and reported in PhD Thesis (Jabeen, 2009),but due to limitations in number of printed pages only the data on fresh and dry biomass is presented in this chapter. Whereas reproductive parameters is presented in terms of number of squares, flower and balls/ plant, seed and lint weight; seed number per plant, seed cotton yield and lint/ seed ratio was recorded at termination of experiment. Fiber characteristics are reported in PhD Thesis (Jabeen, 2009).

Samples of leaf and stem, were taken at grand period of growth, and were dried separately overnight in oven at 700C for the analysis of Na+ and K+ (A.O.A.C., 1984). Concentration of Na+ and K+ cations in samples was measured using a Petracourt PFP.1 Photometer.

Leaves samples were collected at grand period of growth, from 3rd /4th node below the apex for biochemical analysis. i) Chlorophyll was extracted from the leaves in 80%acetone and measured at 663 nm and 645 nm in a Spectrophotometer as outlined by Machlaclam & Zalik, (1963). ii) A total Soluble Carbohydrates content was measured in an aqueous extract of leaf sample according to Ciha & Brun, (1978). Extraction was done in extraction solution (glacial acetic acid: methanol: water, 1:4:5) and optical density was recorded at 490 nm. iii) Protein was estimated by Hartree (1972). Extraction was done in 5% Trichloroacetic acid (TCA) and estimated after color reaction with Folin Ciocalteu's reagent at 650 nm.

Provision of Essential Minerals Through Foliar Sprays 47

Fig. 1. Effect of foliar spray of different mineral nutrients and irrigation water of different

**0.4% sea salt(EC: 6.2 dS/m)**

**0.4% sea salt (EC: 6.2 dS/m)**

**(EC of respective sea salt irrigation water dS/m written in brackets)**

**(EC of respective sea salt irrigation water dS/m written in brackets)**

**0.8% sea salt (EC: 10.8 dS/m)**

**0.8% sea salt (EC: 10.8 dS/m)**

Fig. 2. Effect of foliar spray of different mineral nutrients and irrigation water of different

Foliar Spray with KNO3 + Fe-EDTA Foliar Spray with KNO3 + MnCl2 Foliar Spray with KNO3 + MoO3

salinity levels on Dry Biomass (gm) in *Gossypium hirsutum*.

salinity levels on Fresh Biomass (gm) in *Gossypium hirsutum*.

**0.0% sea salt (EC: 0.6 dS/m)**

**0.0% sea salt (EC: 0.6 dS/m)**

Non Spray

Foliar Spray with Water Foliar Spray with Fe-EDTA Foliar Spray with MnCl2 Foliar Spray with MoO3 Foliar Spray with KNO3 Foliar Spray with KCl Foliar Spray with Urea

**Dry Biomass (gm)/Plant**

**Fresh Biomass (gm)/Plant**

Soil samples were collected fortnightly for salinity measurements. They were dried, saturated with de – ionized water, kept overnight followed by water extraction under vacuum (USDA, 1954). This extract was used for pH and electrical conductivity (dS/m) measurements using a Canterbury Conductivity meter (Model AGR 1000).

Statistical analysis of the data was carried out as outlined by Little & Hills (1975) and Gomez & Gomez (1976). All the data were statistically analyzed by computer program Costat 3.03. and *SPSS VERSION 11*.Mean separation of data was carried out using Duncan Multiple Range Test (Duncan, 1955).

#### **6. Results**

#### **6.1 Vegetative growth**

Interaction of sea salt irrigation and foliar spray of different minerals on vegetative biomass (gm) per plant are presented in Figure 1-2.

#### **6.1.1 Vegetative biomass**

Following conclusions are made on cotton vegetative biomass after consulting results of interaction of sea salt irrigation with foliar spray of different compositions (Figure 1-2).

Soil samples were collected fortnightly for salinity measurements. They were dried, saturated with de – ionized water, kept overnight followed by water extraction under vacuum (USDA, 1954). This extract was used for pH and electrical conductivity (dS/m)

Statistical analysis of the data was carried out as outlined by Little & Hills (1975) and Gomez & Gomez (1976). All the data were statistically analyzed by computer program Costat 3.03. and *SPSS VERSION 11*.Mean separation of data was carried out using Duncan Multiple

Interaction of sea salt irrigation and foliar spray of different minerals on vegetative biomass

Following conclusions are made on cotton vegetative biomass after consulting results of interaction of sea salt irrigation with foliar spray of different compositions (Figure 1-2). i. Vegetative biomass of the plants growing with irrigation water of different sea salt dilutions without any foliar spray remained comparatively less than that of sprayed

ii. Those undergoing with single salt spray of micronutrient (Fe, Mn, Mo) show increase in plant biomass in comparison with non-spray or only water spray, whereas plant

iii. The plants undergoing spray medium for supply of Nitrogen (N) through potassium nitrate or urea though show increase in biomass in comparison with spray of single micronutrients in mentioned above. Whereas, increase in biomass in KNO3 spray was

iv. Supply of potassium (K) through potassium nitrate and potassium chloride shows that biomass of plants sprayed with former is increased than the later. This could be

v. Spray medium of potassium in combination with individual micronutrient (i.e. Fe, Mn and Mo) show significant effect of Fe in increasing plant biomass among these treatments. Their grading would be KNO3 + Mo < KNO3 + Mn < KNO3 + Fe for

vi. Spray medium of K in combination with all the three micronutrient (Fe, Mn and Mo) show significant increase in biomass in comparison with all the above-mentioned

vii. The increase in biomass shown by different medium in control plants follow similar pattern in plants growing at 6.2 and 10.8 dS/m sea salt irrigation water. The slight fluctuation shown in KCl and KNO3 +Fe + Mn + Mo micronutrient spray at earlier

viii. ANOVA for fresh and dry biomass production showed significant difference at level P<0.0001 in respect to salinity and spray, whereas their interaction was not

biomass among themselves was in the order of Mo< Mn <Fe respectively.

significantly more than irrespective of salinity treatments.

attributed as a result of accompanying Nitrogen.

performance at this parameter.

period of growth is non significant.

composition.

significant.

measurements using a Canterbury Conductivity meter (Model AGR 1000).

Range Test (Duncan, 1955).

**6.1 Vegetative growth**

**6.1.1 Vegetative biomass**

with water.

(gm) per plant are presented in Figure 1-2.

**6. Results**

**(EC of respective sea salt irrigation water dS/m written in brackets)**

Fig. 1. Effect of foliar spray of different mineral nutrients and irrigation water of different salinity levels on Fresh Biomass (gm) in *Gossypium hirsutum*.

Fig. 2. Effect of foliar spray of different mineral nutrients and irrigation water of different salinity levels on Dry Biomass (gm) in *Gossypium hirsutum*.

Provision of Essential Minerals Through Foliar Sprays 49

25.00 38.46 +87.01 +80.50 +83.76

10.00 15.38 +11.04 +21.77 +19.32

40.00 61.54 +173.51 +127.89 +132.79

20.00 30.77 +42.86 +50.49 +48.10

10.00 15.38 -12.34 +2.79 -2.88

105.00 161.54 +409.09 +393.12 +426.62

70.00 107.69 +213.64 +238.10 +251.80

55.00 84.62 +110.39 +148.98 +146.04

94.74 150.00 +320.78 +304.54 +326.72

76.47 130.00 +153.90 +159.56 +165.57

82.35 140.00 +203.90 +188.44 +199.69

107.14 214.29 +118.18 +132.20 +133.50

9.09 13.33 +21.43 +34.69 +26.62

0.6 dS/m 69.00 a±4.02 51.00 a±3.96 1224.00 a±3.97 101.49 a±0.01 75.72 a±0.26

6.2 dS/m 61.00 a±4.14 47.00 a±4.59 893.00 b±1.52 38.78 b±22.67 60.36 b±0.14

10.8 dS/m 53.00 a±2.66 34.00 a±3.69 476.00 c±1.99 50.66 c±0.00 33.52 c±0.02

0.6 dS/m 66.00 a±3.94 48.00 a±4.34 836.00 a±4.44 24.70 a±0.02 55.21 a±0.012

6.2 dS/m 59.00 a±3.95 41.00 a±4.82 697.00 b±2.36 71.75 b±0.012 51.31 b±0.02

10.8 dS/m 49.00 a±2.59 30.00 a±3.87 360.00 c±2.36 44.70 c±0.16 29.76 c±0.01

0.6 dS/m 85.00 a±3.83 67.00 a±3.64 1876.00 a±3.68 156.11 a±0.07 122.63 a±0.01

6.2 dS/m 78.00 a±4.53 68.00 a±3.95 1564.00 b±2.75 144.84 b±0.09 110.86 b±1.25

10.8 dS/m 66.00 a±3.00 51.00 a±3.11 918.00 c±2.71 93.33 c±012 67.71 c±0.15

0.6 dS/m 77.00 a±4.36 60.00 a±4.63 1560.33 a±3.38 127.20 a±0.10 97.22 a±0.07

6.2 dS/m 71.00 a±4.3 55.00 a±4.59 1155.00 b±1.51 105.60 b±0.01 78.24 b±0.09

10.8 dS/m 58.00 a±3.0 44.00 a±3.9 748.00 c±1.95 71.28 c±0.01 49.36 c±0.11

0.6 dS/m 81.00 a±4.47 64.00 a±4.63 1728.00 a±3.48 142.72 a±0.01 110.58 a±0.17

6.2 dS/m 74.00 a±4.13 61.00 a±4.59 1403.00 b±1.87 123.21 b±0.01 92.82 b±0.18

10.8 dS/m 62.00 b±2.99 47.00 b±3.9 846.00 c±2.05 80.85 c±0.01 57.55 c±0.01

LSD 0.05 19.97 19.97 1.99 0.01 0.02

LSD 0.05 19.87 19.21 19.24 0.05 0.01

LSD 0.05 19.25 17.25 14.25 1.01 0.21

LSD 0.05 19.97 19.24 14.25 0.14 0.21

LSD 0.05 19.25 125 14.25 14.81 0.21

(g)/plant

Lint weight (gm)/plant

Treatment Flowers/plant Balls/plant Seeds/plant Seed weight

Foliar spray with MnCl2 (5 ppm)

Foliar spray with MoO3 (5 ppm)

Foliar spray with KNO3 (500 ppm)

Foliar spray with KCl(500 ppm)

Foliar spray with Urea (1000 ppm)

#### **6.2 Reproductive growth**

#### **6.2.1 Number of flowers, balls and seed per plant, seed and lint weight / per plant, seed cotton yield, seed / lint ratio**

Reproductive parameters presented in Table 1 are based on production of number of flowers, bolls and seed per plant, weight of seed and lint / per plant, seed cotton yield and seed / lint Ratio as a result of foliar spray of different compositions at cotton plants raised by sea salt irrigation water.

Promotion /reduction percentage calculated on the basis above mentioned parameters is given in the Table 1.

Salinity stresses seemed to have reduced the yield on all the above-mentioned reproductive parameters with increase in salinity of irrigation water. Growth was promoted up to various degrees by foliar spray of mineral nutrients under nonsaline as well as saline conditions.

Increasing salinity of rooting medium has proportionally decreased the yield at all the above-mentioned parameters, which was offset up to various degree by the spray of different mineral nutrients. This effect is well documented in light of seed cotton yield, which is considered main parameter for determining the growth.

ANOVA for reproductive data exhibited significant difference at level P<0.001 in respect to salinity, at level (P<0.0001) spray and while their interaction was not significant.

Reproductive parameters presented in Table 1 are based on production of number of flowers, bolls and seed per plant, weight of seed and lint / per plant, seed cotton yield and seed / lint Ratio as a result of foliar spray of different compositions at cotton plants raised

Promotion /reduction percentage calculated on the basis above mentioned parameters is

Salinity stresses seemed to have reduced the yield on all the above-mentioned reproductive parameters with increase in salinity of irrigation water. Growth was promoted up to various degrees by foliar spray of mineral nutrients under nonsaline as well as saline conditions. Increasing salinity of rooting medium has proportionally decreased the yield at all the above-mentioned parameters, which was offset up to various degree by the spray of different mineral nutrients. This effect is well documented in light of seed cotton yield,

ANOVA for reproductive data exhibited significant difference at level P<0.001 in respect to

(g)/plant

Lint weight (gm)/plant

salinity, at level (P<0.0001) spray and while their interaction was not significant.

0.6 dS/m 58.00 a ±4.08 41.00 a±2.95 902.00 a±5.32 77.49 a±0.01 56.98 a±0.01

6.2 dS/m 51.00 a b±3.8 32.00 a±3.44 512.00 b±3.39 54.08 b±0.01 38.09 b±0.01

10.8 dS/m 35.00 a ±2.64 21.00 a±2.68 252.00 c±2.68 29.19 c±0.01 18.71 c±0.01

0.6 dS/m 60.00 a±3.1 45.00 a±3.19 945.00 a±4.78 85.95 a±4.78 63.47 a±0.02

6.2 dS/m 52.00 a±3.96 34.00 a±3.96 518.00 b±2.18 58.14 b±0.01 41.29 b±0.12

10.8 dS/m 2.58 a±5.77 25.00 a±3.04 300.00 c±2.83 37.25 c±0.01 24.81 c±0.07

0.6 dS/m 74.00 a±4.6 57.00 a±4.41 1425.00 a±3.55 114.57 a±0.01 86.42 a±0.27

6.2 dS/m 69.00 a±4.12 52.00 a±5.30 1040.00 b±1.18 94.12 b±0.01 68.23 b±0.11

10.8 dS/m 55.00 a±2.89 41.00 a±4.22 615.00 c±1.99 61.91 c±0.01 43.32 c±0.18

LSD 0.05 19.97 19.97 1.99 1.99 0.67