Most laboratory incubation methods utilize a homogenized sample created by sieving. However, there are reports that homogenized samples do not well represent the effects of field soil tillage. Laboratory soil should have a physical structure similar to that of the field environment the sample represents, but sieving artificially "tills" soil from undisturbed/notillage environments. This can expose aggregate-protected SOM and enhance the microbial activity, over-estimating the N mineralization. Undisturbed cores may be a better option for laboratory incubations intended to differentiate the impact of tillage on N mineralization [76].

*5.2.2. Covered cylinder method*

The covered cylinder method was developed as a more durable alternative to the buried bag. This technique allows incubation of intact soil cores [81]. Covered cylinders are usually constructed from PVC or metal pipes that are capped to exclude rainfall, which is also assumed to stop inorganic N leaching [82]. Although the tubes are open at the bottom, aeration is less than that in field soil, which might result in higher denitrification potential. Modifications such as using gas permeable caps or perforations in the tube sidewall were often added to promote air exchange and reduce denitrification potential [83, 84]. However, sidewall aeration holes could potentially allow mineralized N loss. Water may enter the soil tubes through aeration holes, causing N leaching at the bottom of the soil column. Furthermore, plant roots may potentially grow into the soil column via aeration holes or the open bottom, absorbing mineralized soil from the tubes. Another major limitation of this technique is that the soil in the tube usually

Relationship of Agronomic Practices to Soil Nitrogen Dynamics

http://dx.doi.org/10.5772/intechopen.77229

65

The basic principle of the covered cylinder method was to limit N leaching by sheltering incubating soil from precipitation. Based on the same principle, there was another *in-situ* method called the "rain shelter" [76, 85], which simply used a shelter over the sampled area to prevent leaching. Except for considerations regarding the quality and durability of the rain shelter and surface water run-on during intense rainfall, the major drawback of this technique is a

Buried polyethylene bags and covered cylinder methods can capture variation in field temperature, while failing to reflect moisture and aeration conditions, which are reported to play a large role in soil N mineralization [28]. An alternative *in-situ* method was proposed that employs ion exchange resins to capture mineralized N leaching from undisturbed soil cylinders [86, 87]. The major modification of this technique is an open cylinder top, which allows precipitation and air to freely enter the intact soil column, and a resin trap at the bottom to capture inorganic N that might otherwise leach from the tube. There are some concerns about whether the soil tube causes abiotic differences between soil in the tube and the surrounding field soil. Wienhold et al. [88] reported that soil inside the cylinders was slightly wetter and warmer than adjacent soil, which likely increases soil N mineralization. They pointed out that the magnitude of change in soil N mineralization was likely much less than the normally observed field core-to-core variation. This method was found to better track true field conditions [79] and has the potential to become a standard

The drawback with intact cores and resin bags is a large resource demand. This technique requires preliminary studies to ensure leached ions are efficiently trapped under field conditions. Resin duality, adsorption capacity, and bypass flow are all factors that can potentially influence resin effectiveness in capturing leached N. The extraction of adsorbed N from the resin is also time-consuming. Kolberg et al. [87] reported that five extractions with KCl were

has a lower soil moisture content than the surrounding field [79].

lack of ability to reflect field soil moisture fluctuations.

*5.2.3. Resin-trap soil core method*

procedure [89].

required to completely release adsorbed N.

#### *5.1.5. Constant temperature versus variable temperature*

Most laboratory incubation methods use a constant temperature, which does not reflect temperature fluctuation in field conditions. Carpenter-Boggs et al. [77] proposed a variable temperature method for laboratory incubation in which soil samples are incubated in a variable temperature incubator (VTI) that mimicked field soil temperatures under a growing corn canopy. They reported that the VTI technique provided a lower sample variance and a smaller initial flush of N mineralization than constant incubation temperature (35°C).

#### **5.2. Field (***in-situ***) incubation methods**

Due to the uncertainty about the extrapolation of laboratory N mineralization values in the field, estimating N mineralization from SOM and crop residues in field conditions would be a compelling research topic for investigators because more efficient N fertilization practices could be hastened if a reliable *in-situ* N mineralization method was developed. So far, there have been three dominant *in-situ* research techniques: buried polyethylene bags, covered cylinders, or resin-trap core methods.

#### *5.2.1. Buried polyethylene bag method*

The buried polyethylene bag method for *in-situ* N mineralization was proposed by Eno [78]. The main driving force behind this technical development was the realization that soil temperature variance results in considerable changes in the soil NO3 − production rate. In that preliminary laboratory study, soil in sealed polyethylene bags had an equal nitrification rate compared to soil contained in ventilated bottles. Polyethylene is permeable to oxygen and carbon dioxide, but no NO3 − diffused through the polyethylene bag during the 24-week incubation period. The preliminary results and polyethylene characteristics mean this technique has the potential to estimate aerobic *in-situ* soil N mineralization.

Although this technique mimics field temperature conditions at a low cost, the technique does not reflect transient field moisture conditions [79]. Elevated NO3 − and carbon dioxide concentrations inside the bags may promote denitrification [80]. Physical damage to the bags by insects or plant roots may result in loss of mineralized N into the field soil via diffusion and mass flow [77, 78]. Another major limitation of this technique is the inevitable disturbance of soil, which does not allow a valid comparison of tillage effects on N mineralization in field conditions [76].

#### *5.2.2. Covered cylinder method*

*5.1.4. Homogenized soil versus undisturbed soil cores*

64 Soil Productivity Enhancement

*5.1.5. Constant temperature versus variable temperature*

**5.2. Field (***in-situ***) incubation methods**

cylinders, or resin-trap core methods.

*5.2.1. Buried polyethylene bag method*

carbon dioxide, but no NO3

Most laboratory incubation methods utilize a homogenized sample created by sieving. However, there are reports that homogenized samples do not well represent the effects of field soil tillage. Laboratory soil should have a physical structure similar to that of the field environment the sample represents, but sieving artificially "tills" soil from undisturbed/notillage environments. This can expose aggregate-protected SOM and enhance the microbial activity, over-estimating the N mineralization. Undisturbed cores may be a better option for laboratory incubations intended to differentiate the impact of tillage on N mineralization [76].

Most laboratory incubation methods use a constant temperature, which does not reflect temperature fluctuation in field conditions. Carpenter-Boggs et al. [77] proposed a variable temperature method for laboratory incubation in which soil samples are incubated in a variable temperature incubator (VTI) that mimicked field soil temperatures under a growing corn canopy. They reported that the VTI technique provided a lower sample variance and a

Due to the uncertainty about the extrapolation of laboratory N mineralization values in the field, estimating N mineralization from SOM and crop residues in field conditions would be a compelling research topic for investigators because more efficient N fertilization practices could be hastened if a reliable *in-situ* N mineralization method was developed. So far, there have been three dominant *in-situ* research techniques: buried polyethylene bags, covered

The buried polyethylene bag method for *in-situ* N mineralization was proposed by Eno [78]. The main driving force behind this technical development was the realization that soil tem-

preliminary laboratory study, soil in sealed polyethylene bags had an equal nitrification rate compared to soil contained in ventilated bottles. Polyethylene is permeable to oxygen and

bation period. The preliminary results and polyethylene characteristics mean this technique

Although this technique mimics field temperature conditions at a low cost, the technique does

tions inside the bags may promote denitrification [80]. Physical damage to the bags by insects or plant roots may result in loss of mineralized N into the field soil via diffusion and mass flow [77, 78]. Another major limitation of this technique is the inevitable disturbance of soil, which does not allow a valid comparison of tillage effects on N mineralization in field conditions [76].

−

diffused through the polyethylene bag during the 24-week incu-

−

production rate. In that

and carbon dioxide concentra-

perature variance results in considerable changes in the soil NO3

has the potential to estimate aerobic *in-situ* soil N mineralization.

not reflect transient field moisture conditions [79]. Elevated NO3

−

smaller initial flush of N mineralization than constant incubation temperature (35°C).

The covered cylinder method was developed as a more durable alternative to the buried bag. This technique allows incubation of intact soil cores [81]. Covered cylinders are usually constructed from PVC or metal pipes that are capped to exclude rainfall, which is also assumed to stop inorganic N leaching [82]. Although the tubes are open at the bottom, aeration is less than that in field soil, which might result in higher denitrification potential. Modifications such as using gas permeable caps or perforations in the tube sidewall were often added to promote air exchange and reduce denitrification potential [83, 84]. However, sidewall aeration holes could potentially allow mineralized N loss. Water may enter the soil tubes through aeration holes, causing N leaching at the bottom of the soil column. Furthermore, plant roots may potentially grow into the soil column via aeration holes or the open bottom, absorbing mineralized soil from the tubes. Another major limitation of this technique is that the soil in the tube usually has a lower soil moisture content than the surrounding field [79].

The basic principle of the covered cylinder method was to limit N leaching by sheltering incubating soil from precipitation. Based on the same principle, there was another *in-situ* method called the "rain shelter" [76, 85], which simply used a shelter over the sampled area to prevent leaching. Except for considerations regarding the quality and durability of the rain shelter and surface water run-on during intense rainfall, the major drawback of this technique is a lack of ability to reflect field soil moisture fluctuations.

#### *5.2.3. Resin-trap soil core method*

Buried polyethylene bags and covered cylinder methods can capture variation in field temperature, while failing to reflect moisture and aeration conditions, which are reported to play a large role in soil N mineralization [28]. An alternative *in-situ* method was proposed that employs ion exchange resins to capture mineralized N leaching from undisturbed soil cylinders [86, 87]. The major modification of this technique is an open cylinder top, which allows precipitation and air to freely enter the intact soil column, and a resin trap at the bottom to capture inorganic N that might otherwise leach from the tube. There are some concerns about whether the soil tube causes abiotic differences between soil in the tube and the surrounding field soil. Wienhold et al. [88] reported that soil inside the cylinders was slightly wetter and warmer than adjacent soil, which likely increases soil N mineralization. They pointed out that the magnitude of change in soil N mineralization was likely much less than the normally observed field core-to-core variation. This method was found to better track true field conditions [79] and has the potential to become a standard procedure [89].

The drawback with intact cores and resin bags is a large resource demand. This technique requires preliminary studies to ensure leached ions are efficiently trapped under field conditions. Resin duality, adsorption capacity, and bypass flow are all factors that can potentially influence resin effectiveness in capturing leached N. The extraction of adsorbed N from the resin is also time-consuming. Kolberg et al. [87] reported that five extractions with KCl were required to completely release adsorbed N.

#### *5.2.4. Other modifications to in-situ incubation methods*

Except for the major design developments mentioned above, some minor modifications to *insitu* incubation methods have been suggested. Hatch et al. [90] proposed a method to combine the soil core with acetylene inhibition, which would limit N loss by nitrification due to uncontrolled soil *in-situ* incubation conditions. The big concern with this modification is that the tube must be sealed at the top, causing a loss in practical application to the field environment if rainfall is a concern. Given consideration on different drainage characteristics in resin-trap soil cores relative to the surrounding soil, Hanselman et al. [79] developed a "new" type of resin-trap soil core method in which resin is mixed with soil to create an artificial uniform soil column. This method is impractical when undisturbed soil structure is a research concern, as in a comparison of conventional and conservation tillage [76].

Tillage affects root growth mainly by changing soil structure, strength, and penetration resistance. Any particular root increases its length through primary growth when cells of the meristem divide, elongate, and push the root tip forward through surrounding materials. Turgor pressure in the elongating cells is the driving force and must be sufficient to overcome cell wall constraints and other additional constraints imposed by the surrounding environment [97]. Compared to conventional plow tillage, numerous studies on grain crops report that no-tillage increases mechanical impedance, which can result in reduced root length density, root surface density, and lower biomass production [98–100]. Similar results were found in a no-tillage burley tobacco study [91, 101]. Furthermore, greater mechanical impedance with no-tillage not only restricts root growth but also changes root morphology, restricting main root axis elongation, stimulating lateral root branching and root thickening

Relationship of Agronomic Practices to Soil Nitrogen Dynamics

http://dx.doi.org/10.5772/intechopen.77229

67

Nutrient supply and distribution (or fertilizer application) can affect root system architecture mainly by signaling [104, 105]. Typically, roots proliferate in volumes where nutrients are most concentrated [106]. However, the mechanisms of plant root response to the different

There have been few studies on the effect of crop rotation on plant root architecture. Given the basic factors controlling root development, the hypothesis is crop rotation may differentially influence root architecture compared to monocropping systems, if rotated with residue-rich or deep-rooted crops that can increase SOM levels and soil structure. In this case, rotation affects root proliferation by changing soil structure in a manner similar to that observed with no-tillage. If rotation involves legumes, more N nutrition is provided than found with monocropping. In this case, rotation could affect root architecture by changing soil nutrient supply

The effects of agronomic practices on crop N uptake not only affect SOM sequestration and soil N mineralization but also alter the soil environment for plant root proliferation. Similarly, in a paper titled "A New Worldview of Soils" [111], soil productivity is broadly defined as the soil's unique ability to supply water, nutrients, air, and heat, among other life-sustaining resources, adjusting that supply to the demands of plants and microbes. Soil resources fall into two main components: (a) nutrients and moisture and (b) an environment suited for root

Agronomic practices reflect agriculture's N management history. Current agronomic practices have two major responsibilities: (1) promote global food production and (2) maintain the agroecosystem environment. This review shows that soil N dynamics have the potential to provide a framework to understand how agronomic practices connect these two responsibilities. Systematically understanding N cycling in the context of a suite of soil and crop management practices provides a foundation to understand, develop, evaluate, and reshape

nutrient elements might be controlled by different pathways and signals [107–110].

in a manner similar to that found with fertilizer application.

growth and microbial activity.

those agronomic practices.

**7. Conclusion**

[102, 103].

#### **5.3. Method selection**

As discussed above, each method, including laboratory and *in-situ* methods, has unique assumptions, advantages, and disadvantages. There is no standard method that will work for every situation. The selection of method depends on the nature of the study, available resources, and site-specific factors. Although laboratory methods might not reflect natural field conditions, they can provide reasonable relative values to estimate differences due to soil type and certain management practices. Zou et al. [91] reported that discarding plant residue in the laboratory incubation method neglects the potential effect of plant residue on soil N mineralization. The primary merit to field incubation is a more practical estimation of N mineralization, which might be more useful in management decision making. However, the substantial time and apparatus requirement for the *in-situ* incubation methods must be considered. Zou et al. [92] reported that soil C and N fractions contribute variably to predict soil N mineralization in different rotation systems, but SOC (which can be calculated from soil organic matter, a common index in the routine test package of many soil testing laboratories) was the best overall NSNM predictor in their study. The principle is that both biotic and abiotic factors control the soil N mineralization process. Knowing the advantage and disadvantage of each method can help the investigator choose the best method while reducing misinterpretation.

## **6. The influence of agronomic practices on root architecture**

Plant roots are a fundamental component of terrestrial ecosystems and function to maintain nutrient and water supply to the plant [92]. Although root system architecture is controlled mainly by genetic factors [93], plant root systems exhibit high developmental plasticity. This plasticity is possible because root development results from continuous propagation of new meristems. In a heterogeneous soil matrix, a wide array of physical, chemical, and biological factors can affect the initiation and activity of root meristems [37]. Previous studies have reported that certain crop root traits enhance productivity in resource-limited environments due to improved nutrient and water scavenging abilities [94–96]. Agronomic practices can influence crop nutrient uptake capacity by affecting the root growth environment.

Tillage affects root growth mainly by changing soil structure, strength, and penetration resistance. Any particular root increases its length through primary growth when cells of the meristem divide, elongate, and push the root tip forward through surrounding materials. Turgor pressure in the elongating cells is the driving force and must be sufficient to overcome cell wall constraints and other additional constraints imposed by the surrounding environment [97]. Compared to conventional plow tillage, numerous studies on grain crops report that no-tillage increases mechanical impedance, which can result in reduced root length density, root surface density, and lower biomass production [98–100]. Similar results were found in a no-tillage burley tobacco study [91, 101]. Furthermore, greater mechanical impedance with no-tillage not only restricts root growth but also changes root morphology, restricting main root axis elongation, stimulating lateral root branching and root thickening [102, 103].

Nutrient supply and distribution (or fertilizer application) can affect root system architecture mainly by signaling [104, 105]. Typically, roots proliferate in volumes where nutrients are most concentrated [106]. However, the mechanisms of plant root response to the different nutrient elements might be controlled by different pathways and signals [107–110].

There have been few studies on the effect of crop rotation on plant root architecture. Given the basic factors controlling root development, the hypothesis is crop rotation may differentially influence root architecture compared to monocropping systems, if rotated with residue-rich or deep-rooted crops that can increase SOM levels and soil structure. In this case, rotation affects root proliferation by changing soil structure in a manner similar to that observed with no-tillage. If rotation involves legumes, more N nutrition is provided than found with monocropping. In this case, rotation could affect root architecture by changing soil nutrient supply in a manner similar to that found with fertilizer application.

The effects of agronomic practices on crop N uptake not only affect SOM sequestration and soil N mineralization but also alter the soil environment for plant root proliferation. Similarly, in a paper titled "A New Worldview of Soils" [111], soil productivity is broadly defined as the soil's unique ability to supply water, nutrients, air, and heat, among other life-sustaining resources, adjusting that supply to the demands of plants and microbes. Soil resources fall into two main components: (a) nutrients and moisture and (b) an environment suited for root growth and microbial activity.

## **7. Conclusion**

*5.2.4. Other modifications to in-situ incubation methods*

in a comparison of conventional and conservation tillage [76].

**5.3. Method selection**

66 Soil Productivity Enhancement

Except for the major design developments mentioned above, some minor modifications to *insitu* incubation methods have been suggested. Hatch et al. [90] proposed a method to combine the soil core with acetylene inhibition, which would limit N loss by nitrification due to uncontrolled soil *in-situ* incubation conditions. The big concern with this modification is that the tube must be sealed at the top, causing a loss in practical application to the field environment if rainfall is a concern. Given consideration on different drainage characteristics in resin-trap soil cores relative to the surrounding soil, Hanselman et al. [79] developed a "new" type of resin-trap soil core method in which resin is mixed with soil to create an artificial uniform soil column. This method is impractical when undisturbed soil structure is a research concern, as

As discussed above, each method, including laboratory and *in-situ* methods, has unique assumptions, advantages, and disadvantages. There is no standard method that will work for every situation. The selection of method depends on the nature of the study, available resources, and site-specific factors. Although laboratory methods might not reflect natural field conditions, they can provide reasonable relative values to estimate differences due to soil type and certain management practices. Zou et al. [91] reported that discarding plant residue in the laboratory incubation method neglects the potential effect of plant residue on soil N mineralization. The primary merit to field incubation is a more practical estimation of N mineralization, which might be more useful in management decision making. However, the substantial time and apparatus requirement for the *in-situ* incubation methods must be considered. Zou et al. [92] reported that soil C and N fractions contribute variably to predict soil N mineralization in different rotation systems, but SOC (which can be calculated from soil organic matter, a common index in the routine test package of many soil testing laboratories) was the best overall NSNM predictor in their study. The principle is that both biotic and abiotic factors control the soil N mineralization process. Knowing the advantage and disadvantage of each method

can help the investigator choose the best method while reducing misinterpretation.

influence crop nutrient uptake capacity by affecting the root growth environment.

Plant roots are a fundamental component of terrestrial ecosystems and function to maintain nutrient and water supply to the plant [92]. Although root system architecture is controlled mainly by genetic factors [93], plant root systems exhibit high developmental plasticity. This plasticity is possible because root development results from continuous propagation of new meristems. In a heterogeneous soil matrix, a wide array of physical, chemical, and biological factors can affect the initiation and activity of root meristems [37]. Previous studies have reported that certain crop root traits enhance productivity in resource-limited environments due to improved nutrient and water scavenging abilities [94–96]. Agronomic practices can

**6. The influence of agronomic practices on root architecture**

Agronomic practices reflect agriculture's N management history. Current agronomic practices have two major responsibilities: (1) promote global food production and (2) maintain the agroecosystem environment. This review shows that soil N dynamics have the potential to provide a framework to understand how agronomic practices connect these two responsibilities. Systematically understanding N cycling in the context of a suite of soil and crop management practices provides a foundation to understand, develop, evaluate, and reshape those agronomic practices.

## **Acknowledgements**

This work publication was supported in part by the National Natural Science Foundation of China Grant (41601330), and the Yunnan Applied Basic Research Project (2017FB074), and the Yunnan Provincial Tobacco Monopoly Bureau Grants (2016YN28,2017YN06,2017YN09). Authors thank Dr. Mark S Coyne for offering the helpful advice and countless reviews on this manuscript.

[9] Lü B, Knoblock J, Riegel JK. Lü Shi Chun Qiu. California: Stanford University Press; 2000 [10] Bationo A. Managing Nutrient Cycles to Sustain Soil Fertility in Sub-Saharan Africa.

Relationship of Agronomic Practices to Soil Nitrogen Dynamics

http://dx.doi.org/10.5772/intechopen.77229

69

[11] Giller KE, Cadisch G, Ehaliotis C, Adams E, Sakala WD, Mafongoya PL. Building soil nitrogen capital in Africa. In: Buresh RJ, Sanchez PA, Calhoun F, editors. Replenishing Soil Fertility in Africa. Madison, WI: Soil Science Society of America and American

[12] White KD. Fallowing, crop rotation, and crop yields in roman times. Agricultural

[13] Smil V. Enriching the earth: Fritz Haber, Carl Bosch, and the transformation of world

[14] Erisman JW, Sutton MA, Galloway J, Klimont Z, Winiwarter W. How a century of ammonia synthesis changed the world. Nature Geoscience. 2008;**1**:636-639. DOI: 10.1038/

[15] Rice C, Smith M, Blevins R. Soil nitrogen availability after long-term continuous notillage and conventional tillage corn production. Soil Science Society of America Journal.

[16] Phillips SH, Young H Jr. No-Tillage Farming. Indianapolis, IN, USA: Reiman Associates;

[17] Horowitz J, Ebel R, Ueda K. "No-till" Farming Is a Growing Practice. USDA Report. 2010

[19] Karlen DL, Varvel GE, Bullock DG, Cruse RM. Crop rotations for the 21st century. In:

[20] Townsend AR, Howarth RW, Bazzaz FA, Booth MS, Cleveland CC, Collinge SK, et al. Human health effects of a changing global nitrogen cycle. Frontiers in Ecology and the

[21] Chen R, Senbayram M, Blagodatsky S, Myachina O, Dittert K, Lin X, et al. Soil C and N availability determine the priming effect: Microbial N mining and stoichiometric decomposition theories. Global Change Biology. 2014;**20**:2356-2367. DOI: 10.1111/gcb.12475

[22] Sollins P, Spycher G, Glassman C. Net nitrogen mineralization from light-and heavyfraction forest soil organic matter. Soil Biology and Biochemistry. 1984;**16**:31-37. DOI:

[23] Six J, Bossuyt H, Degryze S, Denef K. A history of research on the link between (micro) aggregates, soil biota, and soil organic matter dynamics. Soil and Tillage Research.

[18] Bruns HA. Concepts in Crop Rotations. Croatia: InTech Open Access Publisher; 2012

Donald LS, editor. Advances in agronomy. Academic Press; 1994. pp. 1-45

Environment. 2003;**1**:240-246. DOI: 10.2307/3868011

10.1016/0038-0717(84)90122-6

2004;**79**:7-31. DOI: 10.1016/j.still.2004.03.008

1986;**50**:1206-1210. DOI: 10.2136/sssaj1986.03615995005000050023x

Nairobi: Afnet-CIAT; 2004. pp. 127-136

Society of Agronomy; 1997. pp. 151-192

food production. MIT press; 2004. DOI: 10.2307/3985938

History. 1970;**44**(3):281-290

ngeo325

1973

## **Author details**

Congming Zou1,2, Robert C Pearce2 , John H Grove2 , Yan Li1 , Xiaodong Hu1 , Jie Chen1 , Junying Li1 \* and Yan Jin1 \*

\*Address all correspondence to<EMAIL_ADDRESS>and<EMAIL_ADDRESS>
1 Yunnan Academy of Tobacco Agricultural Sciences, Kunming, China

2 Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky USA

## **References**

[9] Lü B, Knoblock J, Riegel JK. Lü Shi Chun Qiu. California: Stanford University Press; 2000

**Acknowledgements**

68 Soil Productivity Enhancement

manuscript.

Junying Li1

**References**

Press; 2012

**Author details**

Congming Zou1,2, Robert C Pearce2

\* and Yan Jin1

\*

This work publication was supported in part by the National Natural Science Foundation of China Grant (41601330), and the Yunnan Applied Basic Research Project (2017FB074), and the Yunnan Provincial Tobacco Monopoly Bureau Grants (2016YN28,2017YN06,2017YN09). Authors thank Dr. Mark S Coyne for offering the helpful advice and countless reviews on this

, John H Grove2

1 Yunnan Academy of Tobacco Agricultural Sciences, Kunming, China

(Massachusetts): Sinauer Associates; 1972. DOI: 10.2307/2484208

Science. 1982;**33**:141-163. DOI: 10.1111/j.1365-2389.1982.tb01755.x

[8] Burke J. Connections. Boston: Brown and Company; 1978

\*Address all correspondence to<EMAIL_ADDRESS>and<EMAIL_ADDRESS>
2 Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky USA

[1] Epstein E. Mineral Nutrition of Plants: Principles and Perspectives. Sunderland

[2] Galloway JN, Cowling EB. Reactive nitrogen and the world: 200 years of change. Ambio: A Journal of the Human Environment. 2002;**31**:64-71. DOI: 10.1579/0044-7447-31.2.64 [3] Marschner H, Marschner P. Marschner's Mineral Nutrition of Higher Plants. Academic

[4] Keeney DR. Nitrogen availability indices. In: Page AL, et al, editors, Methods of Soil Analysis. Part 2. Agronomy Monograph No. 9. Madison, WI: ASA; 1982. pp. 711-733 [5] Boukcim H, Plassard C. Juvenile nitrogen uptake capacities and root architecture of two open-pollinated families of *Picea abies*. Effects of nitrogen source and ectomycorrhizal symbiosis. Journal of Plant Physiology. 2003;**160**:1211-1218. DOI: 10.1078/0176-1617-00973

[6] Tisdall J, Oades JM. Organic matter and water-stable aggregates in soils. Journal of Soil

[7] Curwen EC. Prehistoric Farming of Europe and the Near East. Pt. I., Plough and Pasture,

the Early History of Farming. New York: Henry Schuman; 1953. pp. 3-147

, Yan Li1

, Xiaodong Hu1

, Jie Chen1

,

[24] Zou C, Pearce RC, Grove JH, Coyne MS. Conservation practices in tobacco production increase large aggregates and associated carbon and nitrogen. Soil Science Society of America Journal. 2015;**79**:1760-1770. DOI: 10.2136/sssaj2015.06.0235

[38] Bauer A, Black A. Quantification of the effect of soil organic matter content on soil productivity. Soil Science Society of America Journal. 1994;**58**:185-193. DOI: 10.2136/sssaj19

Relationship of Agronomic Practices to Soil Nitrogen Dynamics

http://dx.doi.org/10.5772/intechopen.77229

71

[39] Cole C, Duxbury J, Freney J, Heinemeyer O, Minami K, Mosier A, et al. Global estimates of potential mitigation of greenhouse gas emissions by agriculture. Nutrient Cycling in

[40] Spalding RF, Exner ME. Occurrence of nitrate in groundwater—A review. Journal of Environmental Quality. 1993;**22**:392-402. DOI: 10.2134/jeq1993.00472425002200030002x

[41] Lupwayi N, Arshad M, Rice W, Clayton G. Bacterial diversity in water-stable aggregates of soils under conventional and zero tillage management. Applied Soil Ecology.

[42] Sullivan L. Soil organic matter, air encapsulation and water-stable aggregation. Journal

[43] Prove B, Loch R, Foley J, Anderson V, Younger D. Improvements in aggregation and infiltration characteristics of a krasnozem under maize with direct drill and stubble

[44] Linquist B, Singleton P, Yost R, Cassman K. Aggregate size effects on the sorption and release of phosphorus in an Ultisol. Soil Science Society of America Journal. 1997;**61**(1):

[45] Zhang W, Yao Y, Sullivan N, Chen Y. Modeling the primary size effects of citrate-coated silver nanoparticles on their ion release kinetics. Environmental Science and Technology.

[46] Bissonnais Yl. Aggregate stability and assessment of soil crustability and erodibility: I. Theory and methodology. European Journal of Soil Science. 1996;**47**:425-437. DOI:

[47] Tisdall J, Oades J. The effect of crop rotation on aggregation in a red-brown earth. Soil

[48] Tisdall J, Oades JM. Organic matter and water-stable aggregates in soils. Journal of Soil

[49] Kemper W, Rosenau R. Aggregate stability and size distribution. In: Klute A, editor. Methods of Soil Analysis. Part 1. Agronomy Monograph. 9. 2nd ed. Madison.WI: ASA

[50] Puget P, Chenu C, Balesdent J. Total and young organic matter distributions in aggregates of silty cultivated soils. European Journal of Soil Science. 1995;**46**:449-459. DOI:

[51] Veum KS, Goyne KW, Kremer R, Motavalli PP. Relationships among water stable aggregates and organic matter fractions under conservation management. Soil Science Society

of America Journal. 2012;**76**:2143-2153. DOI: 10.2136/sssaj2012.0089

of Soil Science. 1990;**41**:529-534. DOI: 10.1111/j.1365-2389.1990.tb00084.x

retention. Soil Research. 1990;**28**:577-590. DOI: 10.1071/SR9900577

Agroecosystems. 1997;**49**:221-228. DOI: 10.1023/a:1009731711346

2001;**16**:251-261. DOI: 10.1016/S0929-1393(00)00123-2

160-166. DOI: 10.2136/sssaj1997.03615995006100010024x

2011;**45**:4422-4428. DOI: 10.1021/es104205a

10.1111/j.1365-2389.1996.tb01843.x

Research. 1980a;**18**:423-433

Science. 1982;**33**:141-163

and SSSA; 1986. pp. 425-442

10.1111/j.1365-2389.1995.tb01341.x

94.03615995005800010027x

[38] Bauer A, Black A. Quantification of the effect of soil organic matter content on soil productivity. Soil Science Society of America Journal. 1994;**58**:185-193. DOI: 10.2136/sssaj19 94.03615995005800010027x

[24] Zou C, Pearce RC, Grove JH, Coyne MS. Conservation practices in tobacco production increase large aggregates and associated carbon and nitrogen. Soil Science Society of

[25] Six J, Elliott E, Paustian K. Soil macroaggregate turnover and microaggregate formation: A mechanism for C sequestration under notillage agriculture. Soil Biology and

[26] Bundy L, Meisinger J. Nitrogen availability indices. In: Weaver RW, Angle JS, Bottomley P S, editors. Methods of Soil Analysis: Part 2. SSSA, Madison, WI, USA: Microbiological

[27] Goncalves J, Carlyle J. Modelling the influence of moisture and temperature on net nitrogen mineralization in a forested sandy soil. Soil Biology and Biochemistry. 1994;**26**:

[28] Sierra J.Temperature and soil moisture dependence of N mineralization in intact soil cores. Soil Biology and Biochemistry. 1997;**29**:1557-1563. DOI: 10.1016/S0038-0717(96)00288-X

[29] Zech W, Senesi N, Guggenberger G, Kaiser K, Lehmann J, Miano TM, et al. Factors controlling humification and mineralization of soil organic matter in the tropics. Geoderma.

[30] Gill K, Jarvis S, Hatch D. Mineralization of nitrogen in long-term pasture soils: Effects of

[31] Van Der Krift TA, Berendse V. The effect of plant species on soil nitrogen mineralization.

[32] Binkley D, Hart SC. The components of nitrogen availability assessments in forest soils. Advances in Soil Science. Springer; 1989. pp. 57-112. DOI: 10.1007/978-1-4613-8847-0\_2

[33] Hart SC, Stark JM, Davidson EA, Firestone MK. Nitrogen mineralization, immobilization, and nitrification. In: Weaver RW, Angle JS, Bottomley PS, editors. Methods of Soil Analysis: Part 2. SSSA, Madison, WI, USA: Microbiological and Biochemical Properties;

[34] Griffin T, Honeycutt C, Albrecht S, Sistani K, Torbert H, Wienhold B, et al. Nationally coordinated evaluation of soil nitrogen mineralization rate using a standardized aerobic incubation protocol. Communications in Soil Science and Plant Analysis. 2007;**39**:257-

[35] Gastal F, Lemaire G. N uptake and distribution in crops: An agronomical and ecophysiological perspective. Journal of Experimental Botany. 2002;**53**:789-799. DOI: 10.1093/

[36] Clark RT, MacCurdy RB, Jung JK, Shaff JE, McCouch SR, Aneshansley DJ, et al. Threedimensional root phenotyping with a novel imaging and software platform. Plant

[37] Lynch J. Root architecture and plant productivity. Plant Physiology. 1995;**109**(1):7

Physiology. 2011;**156**:455-465. DOI: 10.1104/pp.110.169102

management. Plant and Soil. 1995;**172**:153-162. DOI: 10.1007/BF00020869

Journal of Ecology. 2001;**89**:555-561. DOI: 10.1046/j.0022-0477.2001.00580.x

America Journal. 2015;**79**:1760-1770. DOI: 10.2136/sssaj2015.06.0235

Biochemistry. 2000;**32**:2099-2103. DOI:10.1016/S0038-0717(00)00179-6

and Biochemical Properties; 1994. pp. 951-984

1557-1564. DOI: 10.1016/0038-0717(94)90098-1

1997;**79**:117-161. DOI: 10.1016/S0016-7061(97)00040-2

1994. pp. 985-1018

70 Soil Productivity Enhancement

jexbot/53.370.789

268. DOI: 10.1080/00103620701759285

[52] Angers DA, Giroux M. Recently deposited organic matter in soil water-stable aggregates. Soil Science Society of America Journal. 1996;**60**:1547-1551. DOI: 10.2136/sssaj199 6.03615995006000050037x

[65] Beauchamp E, Reynolds W, Brasche-Villeneuve D, Kirby K. Nitrogen mineralization kinetics with different soil pretreatments and cropping histories. Soil Science Society of America Journal. 1986;**50**:1478-1483. DOI: 10.2136/sssaj1986.03615995005000060020x [66] Honeycutt C, Griffin T, Wienhold BJ, Eghball B, Albrecht S, Powell JM, et al. Protocols for nationally coordinated laboratory and field research on manure nitrogen mineralization. Communications in Soil Science and Plant Analysis. 2005;**36**:2807-2822. DOI:

Relationship of Agronomic Practices to Soil Nitrogen Dynamics

http://dx.doi.org/10.5772/intechopen.77229

73

[67] Allison F, Sterling LD. Nitrate formation from soil organic matter in relation to total nitrogen and cropping practices. Soil Science. 1949;**67**:239-252. DOI: 10.1097/00010694-194903000-

[68] Stanford G, Hanway J. Predicting nitrogen fertilizer needs of Iowa soils: II. A simplified technique for determining relative nitrate production in soils. Soil Science Society of

[69] Stanford G, Smith S. Nitrogen mineralization potentials of soils. Soil Science Society of

[70] Smith JL, Schnabel R, McNeal B, Campbell G. Potential errors in the first-order model for estimating soil nitrogen mineralization potentials. Soil Science Society of America

[71] Heumann S, Böttcher J, Springob G. N mineralization parameters of sandy arable soils. Journal of Plant Nutrition and Soil Science. 2002;**165**:441-450. DOI: 10.1002/1522-2624

[72] Mikha MM, Rice CW, Milliken GA. Carbon and nitrogen mineralization as affected by drying and wetting cycles. Soil Biology and Biochemistry. 2005;**37**:339-347. DOI:

[73] Miller AE, Schimel JP, Meixner T, Sickman JO, Melack JM. Episodic rewetting enhances carbon and nitrogen release from chaparral soils. Soil Biology and Biochemistry.

[74] Wu J, Brookes PC. The proportional mineralisation of microbial biomass and organic matter caused by air-drying and rewetting of a grassland soil. Soil Biology and

[75] Xiang SR, Doyle A, Holden PA, Schimel JP. Drying and rewetting effects on C and N mineralization and microbial activity in surface and subsurface California grassland soils. Soil Biology and Biochemistry. 2008;**40**:2281-2289. DOI: 10.1016/j.soilbio.2008.05.004 [76] Rice C, Grove J, Smith M. Estimating soil net nitrogen mineralization as affected by tillage and soil drainage due to topographic position. Canadian Journal of Soil Science.

[77] Carpenter-Boggs L, Pikul JL, Vigil MF, Riedell WE. Soil nitrogen mineralization influenced by crop rotation and nitrogen fertilization. Soil Science Society of America Journal.

Journal. 1980;**44**:996-1000. DOI: 10.2136/sssaj1980.03615995004400050025x

America Journal. 1955;**19**:74-77. DOI: 10.2136/sssaj1955.03615995001900010018x

10.1080/00103620500304184

America Journal. 1972;**36**:465-472

(200208)165:43.0.CO;2-F

10.1016/j.soilbio.2004.08.003

2005;**37**:2195-2204. DOI: 10.1016/j.soilbio.2005.03.021

1987;**67**:513-520. DOI: 10.4141/cjss87-048

2000;**64**:2038-2045. DOI: 10.2136/sssaj2000.6462038x

Biochemistry. 2005;**37**:507-515. DOI: 10.1016/j.soilbio.2004.07.043

00005

[65] Beauchamp E, Reynolds W, Brasche-Villeneuve D, Kirby K. Nitrogen mineralization kinetics with different soil pretreatments and cropping histories. Soil Science Society of America Journal. 1986;**50**:1478-1483. DOI: 10.2136/sssaj1986.03615995005000060020x

[52] Angers DA, Giroux M. Recently deposited organic matter in soil water-stable aggregates. Soil Science Society of America Journal. 1996;**60**:1547-1551. DOI: 10.2136/sssaj199

[53] Beare M, Hendrix P, Coleman D. Water-stable aggregates and organic matter fractions in conventional-and no-tillage soils. Soil Science Society of America Journal. 1994;**58**:

[54] Cambardella C, Elliott E. Carbon and nitrogen distribution in aggregates from cultivated and native grassland soils. Soil Science Society of America Journal. 1993;**57**:1071-1076.

[55] Brye K, Olk DC, Schmid BT.Rice rotation and tillage effects on soil aggregation and aggregate carbon and nitrogen dynamics. Soil Science Society of America Journal. 2012;**76**:

[56] Haynes R, Naidu R. Influence of lime, fertilizer and manure applications on soil organic matter content and soil physical conditions: A review. Nutrient Cycling in Agroeco-

[57] Kong AY, Six J, Bryant DC, Denison RF, Van Kessel C. The relationship between carbon input, aggregation, and soil organic carbon stabilization in sustainable cropping systems. Soil Science Society of America Journal. 2005;**69**:1078-1085. DOI: 10.2136/sssaj2004.0215

[58] Sainju UM, Caesar-Tonthat T, Jabro JD. Carbon and nitrogen fractions in dryland soil aggregates affected by long-term tillage and cropping sequence. Soil Science Society of

[59] Six J, Elliott E, Paustian K, Doran J. Aggregation and soil organic matter accumulation in cultivated and native grassland soils. Soil Science Society of America Journal.

[60] West TO, Post WM. Soil organic carbon sequestration rates by tillage and crop rotation. Soil Science Society of America Journal. 2002;**66**:1930-1946. DOI: 10.2136/sssaj2002.1930

[61] Wright AL, Hons FM. Soil carbon and nitrogen storage in aggregates from different tillage and crop regimes. Soil Science Society of America Journal. 2005;**69**:141-147. DOI:

[62] Mulvaney R, Khan S, Ellsworth T. Synthetic nitrogen fertilizers deplete soil nitrogen: A global dilemma for sustainable cereal production. Journal of Environmental Quality.

[63] Brown KH, Bach EM, Drijber RA, Hofmockel KS, Jeske ES, Sawyer JE, et al. A long-term nitrogen fertilizer gradient has little effect on soil organic matter in a high-intensity maize production system. Global Change Biology. 2014;**20**:1339-1350. DOI: 10.1111/gcb.12519

[64] Su YZ, Wang F, Suo DR, Zhang ZH, Du MW. Long-term effect of fertilizer and manure application on soil-carbon sequestration and soil fertility under the wheat–wheat–maize cropping system in Northwest China. Nutrient Cycling in Agroecosystems. 2006;**75**:

777-786. DOI: 10.2136/sssaj1994.03615995005800030020x

systems. 1998;**51**:123-137. DOI: 10.1023/A:1009738307837

America Journal. 2009;**73**:1488-1495. DOI: 10.2136/sssaj2008-0405

1998;**62**:1367-1377. DOI: 10.2136/sssaj1998.03615995006200050032x

DOI: 10.2136/sssaj1993.03615995005700040032x

994-1004. DOI: 10.2136/sssaj2010.0436

10.1002/9780470777923.ch16

2009;**38**:2295-2314. DOI: 10.2134/jeq2008.0527

285-295. DOI: 10.1007/s10705-006-9034-x

6.03615995006000050037x

72 Soil Productivity Enhancement

[78] Eno CF. Nitrate production in the field by incubating the soil in polyethylene bags. Soil Science Society of America Journal. 1960;**24**:277-279. DOI: 10.2136/sssaj1960.0361599500<PHONE_NUMBER>x

[91] Zou C, Pearce RC, Grove JH, Coyne MS. Laboratory vs. *in situ* resin-core methods to estimate net nitrogen mineralization for comparison of rotation and tillage practices. Journal of Plant Nutrition and Soil Science. 2017;**180**:294-301. DOI: 10.1002/

Relationship of Agronomic Practices to Soil Nitrogen Dynamics

http://dx.doi.org/10.5772/intechopen.77229

75

[92] Zou C, Pearce RC, Grove JH, Coyne MS, Roualdes EA, Li Y. Stability of indicators for net soil nitrogen mineralization in tobacco rotation and tillage systems. Soil Science

[93] de Dorlodot S, Forster B, Pagès L, Price A, Tuberosa R, Draye X. Root system architecture: Opportunities and constraints for genetic improvement of crops. Trends in Plant

[94] Liao H, Rubio G, Yan X, Cao A, Brown KM, Lynch JP. Effect of phosphorus availability on basal root shallowness in common bean. Plant and Soil. 2001;**232**:69-79. DOI: 10.1023/A:1010

[95] Lynch JP. Root phenes for enhanced soil exploration and phosphorus acquisition: Tools for future crops. Plant Physiology. 2011;**156**:1041-1049. DOI: 10.1104/pp.111.175414 [96] Ribaut JM, Betran J, Monneveux P, Setter T. Drought tolerance in maize. In: Bennetzen JL, Hake SC, editors. Handbook of Maize: Its Biology. New York: Springer; 2009. pp. 311-344.

[97] Foy C, Carson E. The plant root and its environment. In: Carson EW, editor. Proceedings of an Institute Sponsored by the Southern Regional Education Board, held at Virginia

[98] Gajri P, Arora V, Prihar S.Tillage management for efficient water and nitrogen use in wheat following rice. Soil and Tillage Research. 1992;**24**:167-182. DOI: 10.1016/0167-1987(92)

[99] Guan D, Al-Kaisi MM, Zhang Y, Duan L, Tan W, Zhang M, et al. Tillage practices affect biomass and grain yield through regulating root growth, root-bleeding sap and nutrients uptake in summer maize. Field Crops Research. 2014;**157**:89-97. DOI: 10.1016/j.

[100] Mosaddeghi M, Mahboubi A, Safadoust A. Short-term effects of tillage and manure on some soil physical properties and maize root growth in a sandy loam soil in western

Iran. Soil and Tillage Research. 2009;**104**:173-179. DOI: 10.1016/j.still.2008.10.011 [101] Zartman R, Phillips R, Atkinson W. Tillage and nitrogen influence on root densities and

[102] Cook A, Marriott C, Seel W, Mullins C. Effects of soil mechanical impedance on root and shoot growth of *Lolium perenne* L. *Agrostis capillaris* and *Trifolium repens* L. Journal

[103] Griffith DR, Mannering JV, Moldenhauer WC. Conservation tillage in the eastern Corn Belt [United States]. Journal of Soil and Water Conservation. 1977;**32**:20-28

yield of burley tobacco. Tobacco International. 1976;**178**(18):35-38

of Experimental Botany. 1996;**47**:1075-1084. DOI: 10.1093/jxb/47.8.1075

Society of America Journal. 2018;**82**:483-492. DOI:10.2136/sssaj2017.08.0263

Science. 2007;**12**:474-481. DOI: 10.1016/j.tplants.2007.08.012

Polytechnic Institute and State University, July 5-16, 1971. 1974

jpln.201600571

381919003

90099-W

fcr.2013.12.015

DOI: 10.1007/978-0-387-79418-1\_16

[91] Zou C, Pearce RC, Grove JH, Coyne MS. Laboratory vs. *in situ* resin-core methods to estimate net nitrogen mineralization for comparison of rotation and tillage practices. Journal of Plant Nutrition and Soil Science. 2017;**180**:294-301. DOI: 10.1002/ jpln.201600571

[78] Eno CF. Nitrate production in the field by incubating the soil in polyethylene bags. Soil Science Society of America Journal. 1960;**24**:277-279. DOI: 10.2136/sssaj1960.0361599500

[79] Hanselman TA, Graetz DA, Obreza TA. A comparison of *in situ* methods for measuring net nitrogen mineralization rates of organic soil amendments. Journal of Environmental

[80] Subler S, Parmelee R, Allen M. Comparison of buried bag and PVC core methods for in situ measurement of nitrogen mineralization rates in an agricultural soil. Communications in Soil Science and Plant Analysis. 1995;**26**:2369-2381. DOI: 10.1080/00103629509369454

[81] Raison R, Connell M, Khanna P. Methodology for studying fluxes of soil mineral-N *in situ*. Soil Biology and Biochemistry. 1987;**19**:521-530. DOI: 10.1016/0038-0717(87)90094-0

[82] Adams M, Attiwill P. Nutrient cycling and nitrogen mineralization in eucalypt forests of South-Eastern Australia. Plant and Soil. 1986;**92**:341-362. DOI: 10.1007/BF02372483

[83] Dou H, Alva A, Khakural B. Nitrogen mineralization from citrus tree residues under different production conditions. Soil Science Society of America Journal. 1997;**61**:1226-1232.

[84] Rapp M, Leclerc MC, Lossaint P. The nitrogen economy in a *Pinus pinea* L. stand. Forest Ecology and Management. 1979;**2**:221-231. DOI: 10.1016/0378-1127(79)90048-3

[85] Powlson D. Effect of cultivation on the mineralization of nitrogen in soil. Plant and Soil.

[86] DiStefano JF, Gholz H. A proposed use of ion exchange resins to measure nitrogen mineralization and nitrification in intact soil cores. Communications in Soil Science and

[87] Kolberg R, Rouppet B, Westfall D, Peterson G. Evaluation of an *in situ* net soil nitrogen mineralization method in dryland agroecosystems. Soil Science Society of America

[88] Wienhold BJ, Varvel GE, Wilhelm WW. Container and installation time effects on soil moisture, temperature, and inorganic nitrogen retention for an *in situ* nitrogen mineralization method. Communications in Soil Science and Plant Analysis. 2009;**40**:2044-2057.

[89] Khanna PK, Raison RJ. *In situ* core methods for estimating soil mineral-N fluxes: Reevaluation based on 25 years of application and experience. Soil Biology and Biochem-

[90] Hatch D, Jarvis S, Philipps L. Field measurement of nitrogen mineralization using soil core incubation and acetylene inhibition of nitrification. Plant and Soil. 1990;**124**:97-107.

Plant Analysis. 1986;**17**:989-998. DOI: 10.1080/00103628609367767

istry. 2013;**64**:203-210. DOI: 10.1016/j.soilbio.2012.09.004

Journal. 1997;**61**:504-508. DOI: 10.2136/sssaj1997.03615995006100020019x

Quality. 2004;**33**:1098-1105. DOI: 10.2134/jeq2004.1098

DOI: 10.2136/sssaj1997.03615995006100040031x

1980;**57**:151-153. DOI: 10.1007/BF02139653

DOI: 10.1080/00103620902960575

DOI: 10.1007/BF00010937

2400040019x

74 Soil Productivity Enhancement

[104] López-Bucio J, Cruz Ramı́rez A, Herrera-Estrella L. The role of nutrient availability in regulating root architecture. Current Opinion in Plant Biology. 2003;**6**:280-287. DOI: 10.1016/S1369-5266(03)00035-9

**Section 3**

**Policy on Fertilizer Use**

**Policy on Fertilizer Use**

[104] López-Bucio J, Cruz Ramı́rez A, Herrera-Estrella L. The role of nutrient availability in regulating root architecture. Current Opinion in Plant Biology. 2003;**6**:280-287. DOI:

[105] Robinson D. Resource capture by localized root proliferation: Why do plants bother?

[106] Robinson D. The responses of plants to non-uniform supplies of nutrients. New

[107] Mantelin S, Touraine B. Plant growth-promoting bacteria and nitrate availability: Impacts on root development and nitrate uptake. Journal of Experimental Botany.

[108] Williamson LC, Ribrioux SP, Fitter AH, Leyser HO. Phosphate availability regulates root system architecture in Arabidopsis. Plant Physiology. 2001;**126**:875-882. DOI: 10.1104/

[109] Zhang H, Forde BG. An Arabidopsis MADS box gene that controls nutrient-induced changes in root architecture. Science. 1998;**279**:407-409. DOI: 10.1126/science.279.5349.407

[110] Zhang H, Jennings A, Barlow PW, Forde BG. Dual pathways for regulation of root branching by nitrate. Proceedings of the National Academy of Sciences. 1999;**96**:6529-

[111] Lin H. A new worldview of soils. Soil Science Society of America Journal. 2014;**78**:1831-

Annals of Botany. 1996;**77**:179-186. DOI: 10.1006/anbo.1996.0020

Phytologist. 1994;**127**:635-674. DOI: 10.1111/j.1469-8137.1994.tb02969.x

10.1016/S1369-5266(03)00035-9

2004;**55**:27-34. DOI: 10.1093/jxb/erh010

6534. DOI: 10.1073/pnas.96.11.6529

1844. DOI: 10.2136/sssaj2014.04.0162

pp.126.2.875

76 Soil Productivity Enhancement

**Chapter 5**

Provisional chapter

**Fostering Fertilizer Use and Welfare Distribution in**

DOI: 10.5772/intechopen.78043

This chapter attempts to assess the way the welfare effect is distributed among various players of the fertilizer supply chain and how fertilizer use can be promoted using micro fertilization technology. As policy debates over fertilizer use promotion have not yet come full circle, this chapter derives important implications for policy and practice. In particular, illustrations and economic-surplus effects framework were used to indicate expected impacts of fertilizer microdosing on crop yields and welfare. Lowdimension diagrammatic analysis using supply and demand curves was used together with detailed assessment of actors' interactions in the fertilizer supply chain. In terms of welfare, crop producers, consumers and other market agents gain more if fertilizer microdosing is adopted by farmers. However, the magnitude of welfare effects varies as the slope of demand and supply curves change due to marginal fertilizer costs, crop prices and yield responses. Other influencing factors are soil moisture, the microdose rate, cropping system and general farm management practices. Thus, fertilizer microdosing can easily foster fertilizer use if the country elites implement a rational consistent policy, hence improving the welfare of players if adoption of the technology

Keywords: welfare distribution, economic-surplus model, fertilizer microdosing, supply

A plethora of scientific literature indicates that hunger is caused by poor soil fertility. In Sub-Saharan Africa, the gap between cereal consumption and production is the largest compared to other continents. The productivity of most food crops is not as good as expected [1, 2]. Thus, it is possible to secure food in African countries if soil fertility is improved as well as if there is

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

Fostering Fertilizer Use and Welfare Distribution in

**Tanzania: Implications for Policy and Practice**

Tanzania: Implications for Policy and Practice

Additional information is available at the end of the chapter

is reinforced with an efficient fertilizer supply chain.

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.78043

Lutengano Mwinuka

Lutengano Mwinuka

Abstract

chain, Tanzania

1. Introduction

#### **Fostering Fertilizer Use and Welfare Distribution in Tanzania: Implications for Policy and Practice** Fostering Fertilizer Use and Welfare Distribution in Tanzania: Implications for Policy and Practice

DOI: 10.5772/intechopen.78043

Lutengano Mwinuka Lutengano Mwinuka

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.78043

#### Abstract

This chapter attempts to assess the way the welfare effect is distributed among various players of the fertilizer supply chain and how fertilizer use can be promoted using micro fertilization technology. As policy debates over fertilizer use promotion have not yet come full circle, this chapter derives important implications for policy and practice. In particular, illustrations and economic-surplus effects framework were used to indicate expected impacts of fertilizer microdosing on crop yields and welfare. Lowdimension diagrammatic analysis using supply and demand curves was used together with detailed assessment of actors' interactions in the fertilizer supply chain. In terms of welfare, crop producers, consumers and other market agents gain more if fertilizer microdosing is adopted by farmers. However, the magnitude of welfare effects varies as the slope of demand and supply curves change due to marginal fertilizer costs, crop prices and yield responses. Other influencing factors are soil moisture, the microdose rate, cropping system and general farm management practices. Thus, fertilizer microdosing can easily foster fertilizer use if the country elites implement a rational consistent policy, hence improving the welfare of players if adoption of the technology is reinforced with an efficient fertilizer supply chain.

Keywords: welfare distribution, economic-surplus model, fertilizer microdosing, supply chain, Tanzania

#### 1. Introduction

A plethora of scientific literature indicates that hunger is caused by poor soil fertility. In Sub-Saharan Africa, the gap between cereal consumption and production is the largest compared to other continents. The productivity of most food crops is not as good as expected [1, 2]. Thus, it is possible to secure food in African countries if soil fertility is improved as well as if there is

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

an understanding of what works for smallholder farmers in rural areas [3]. Although smallscale farmers are a potential source of economic growth [4], more efforts are needed to rescue them from operating under low inputs and rain-fed agricultural conditions, which result in low yields and profits [5, 6]. It is worth noting that fertilizers account for the largest proportion of production costs component when compared with other farm inputs. Nevertheless, farmers in Tanzania have low levels of fertilizer use, hence low productivity [7, 8]. In this light, fertilizer use should be encouraged in order to improve productivity among farmers.

technology. Second, in addition to contributing to the growing knowledge base on the welfare effects as prices of commodities change, the researcher extended the role of price analysis on welfare, beyond the output by considering the input (fertilizer) prices [21] and inter-temporal effects [22]. This study focuses on the way market functioning can affect the incentives of fertilizer supply chain actors using the available information gathered from previous studies. An investigation of how the input market should be improved is pertinent in understanding the underlying causes of low modern input use among producers and recommending best

Fostering Fertilizer Use and Welfare Distribution in Tanzania: Implications for Policy and Practice

http://dx.doi.org/10.5772/intechopen.78043

81

The agricultural sector is controlled by market fundamentals such as forces of supply and demand. However, in reality, this is not always the case, as the market alone is not enough to allow equitable, sustained and stable growth [13]. In this regard, the demonstration of the partial equilibrium model using forces of supply and demand was used in this chapter, and a relevant literature review was undertaken to determine whether the supply chain performance and fertilizer markets functioning can improve through policy associated actions and government interventions. However, the main disadvantage of the economic-surplus approaches as reported is that the reliability of the findings usually depends on the extent to which the underlying parameters represent local conditions [25]. Keeping this constraint in mind, economic-surplus effects were determined and augmented with a thorough assessment of the fertilizer supply chain using Tanzania as a case. Integration of related approaches may be useful in support decisions, for instance, about better allocation of resources for promoting

As suggested by [26], this chapter uses fertilizer microdosing as an opportunity available for upgrading the agri-food value chains in Tanzania, targeting potential food crops [27]. It is the upgrading option that is within the reach of the weakest actor, i.e., the smallholder farmers [28]. An illustration and framework development of economic surplus (welfare and distribution) effects of the farm-level technology is of great importance for understanding the likely spillover of the new innovation [29]. Low-dimension diagrammatic analysis of expected impacts was used, based on the basic economic theory of supply and demand. In addition, a downward sloping demand curve and an upward sloping supply curve were used to characterize the domestic market for food crop produce. Thus, the choice of this methodological line comes from the fact that the economic-surplus approach requires the least information, is relatively easier to use and gives reliable results. According to [30], this method provides a relatively simple and flexible approach to understanding the value of adopting new technology by allowing for the comparison of the situations of with and without the use of the new technology. Details of the welfare impact results are portrayed in Figure 1 and are further

practice and policy for implementation [19, 23, 24].

2. Methods

fertilizer use and investments [2].

explained in the subsequent sections.

2.1. Economic-surplus model for welfare analysis

Investing on fertilizer use by smallholder farmers, including the application of recommended rates has been risky due to the scarcity of fertilizers and the unpredictability of rainfall [9, 10]. Fertilizer microdosing is likely to be a unique initiative that can encourage fertilizer use among the farmers community. The fertilizer microdosing technique is based on localized placement of small doses of mineral fertilizers ranging from 25–75% of the common rates at the base of the plants at sowing or shortly after seed germination instead of spreading fertilizers evenly across the field [9, 11]. This chapter focuses on how fertilizer use can be fostered to improve welfare among potential stakeholders of the fertilizer supply chain. Tanzania has been used as the fertilizer microdosing technology is rather new within the country and more understanding is needed associated with its impacts on fertilizer supply chain [12, 13]. In view of this, key implications are derived for policy and practice with the emphasis on fertilizer microdosing as an innovative low input technology that can replenish soil nutrients.

Some studies, although limited, seem to confirm that yields do relatively increase when fertilizer microdosing is applied [9, 14, 15]. However, in such studies, the issue of welfare distribution effects was rarely included to consider the benefits of fertilizer microdosing to producers and consumers [2, 11, 16]. In this regard, a separate welfare effects analysis urgently needs to be undertaken, targeting this farm-level technology [17], as it can easily be adopted by smallholder farmers in rural areas [18]. The available literature seems to be inapplicable as it mainly presents the impact of fertilizer microdosing in terms of yield responses. Actual impacts, indicating interactions between demand and supply and the role of price mechanisms have been marginally featured in the available literature. Likewise, the coverage on interactions of fertilizer supply chain actors at the national level seems to be scanty. Some of the key questions that remain unanswered include the following: what could be the impact of adopting fertilizer microdosing on the supply side and produced food prices? What are the likely changes in demand/supply of food crop produce, and to what extent is the resulting impact likely to differ from the cost of fertilizer used or return on investment?

While reviewing past economic studies related to fertilizer use, the researcher found inadequate information on welfare effects distributions of farm input use [15, 19]. In view of this, in the present chapter, the researcher build on the earlier studies to assess the welfare effects of fertilizer microdosing based on yield and prices. Based on this objective of the chapter, the contributions are twofold: first, little attention was noted on issues associated with crop responses and welfare in the on-going policy debates over modern input promotion [3, 20]. Thus, the researcher sought to learn from the economic theory and provide insights into the welfare effects that are likely to occur if fertilizer microdosing is adopted. In the same vein, the researcher sought to ascertain whether key actors, particularly farmers, are better off than before, and what factors are important for determining the outcomes, hence promote the technology. Second, in addition to contributing to the growing knowledge base on the welfare effects as prices of commodities change, the researcher extended the role of price analysis on welfare, beyond the output by considering the input (fertilizer) prices [21] and inter-temporal effects [22]. This study focuses on the way market functioning can affect the incentives of fertilizer supply chain actors using the available information gathered from previous studies. An investigation of how the input market should be improved is pertinent in understanding the underlying causes of low modern input use among producers and recommending best practice and policy for implementation [19, 23, 24].

## 2. Methods

an understanding of what works for smallholder farmers in rural areas [3]. Although smallscale farmers are a potential source of economic growth [4], more efforts are needed to rescue them from operating under low inputs and rain-fed agricultural conditions, which result in low yields and profits [5, 6]. It is worth noting that fertilizers account for the largest proportion of production costs component when compared with other farm inputs. Nevertheless, farmers in Tanzania have low levels of fertilizer use, hence low productivity [7, 8]. In this light,

Investing on fertilizer use by smallholder farmers, including the application of recommended rates has been risky due to the scarcity of fertilizers and the unpredictability of rainfall [9, 10]. Fertilizer microdosing is likely to be a unique initiative that can encourage fertilizer use among the farmers community. The fertilizer microdosing technique is based on localized placement of small doses of mineral fertilizers ranging from 25–75% of the common rates at the base of the plants at sowing or shortly after seed germination instead of spreading fertilizers evenly across the field [9, 11]. This chapter focuses on how fertilizer use can be fostered to improve welfare among potential stakeholders of the fertilizer supply chain. Tanzania has been used as the fertilizer microdosing technology is rather new within the country and more understanding is needed associated with its impacts on fertilizer supply chain [12, 13]. In view of this, key implications are derived for policy and practice with the emphasis on fertilizer microdosing as

Some studies, although limited, seem to confirm that yields do relatively increase when fertilizer microdosing is applied [9, 14, 15]. However, in such studies, the issue of welfare distribution effects was rarely included to consider the benefits of fertilizer microdosing to producers and consumers [2, 11, 16]. In this regard, a separate welfare effects analysis urgently needs to be undertaken, targeting this farm-level technology [17], as it can easily be adopted by smallholder farmers in rural areas [18]. The available literature seems to be inapplicable as it mainly presents the impact of fertilizer microdosing in terms of yield responses. Actual impacts, indicating interactions between demand and supply and the role of price mechanisms have been marginally featured in the available literature. Likewise, the coverage on interactions of fertilizer supply chain actors at the national level seems to be scanty. Some of the key questions that remain unanswered include the following: what could be the impact of adopting fertilizer microdosing on the supply side and produced food prices? What are the likely changes in demand/supply of food crop produce, and to what extent is the resulting

While reviewing past economic studies related to fertilizer use, the researcher found inadequate information on welfare effects distributions of farm input use [15, 19]. In view of this, in the present chapter, the researcher build on the earlier studies to assess the welfare effects of fertilizer microdosing based on yield and prices. Based on this objective of the chapter, the contributions are twofold: first, little attention was noted on issues associated with crop responses and welfare in the on-going policy debates over modern input promotion [3, 20]. Thus, the researcher sought to learn from the economic theory and provide insights into the welfare effects that are likely to occur if fertilizer microdosing is adopted. In the same vein, the researcher sought to ascertain whether key actors, particularly farmers, are better off than before, and what factors are important for determining the outcomes, hence promote the

fertilizer use should be encouraged in order to improve productivity among farmers.

an innovative low input technology that can replenish soil nutrients.

80 Soil Productivity Enhancement

impact likely to differ from the cost of fertilizer used or return on investment?

The agricultural sector is controlled by market fundamentals such as forces of supply and demand. However, in reality, this is not always the case, as the market alone is not enough to allow equitable, sustained and stable growth [13]. In this regard, the demonstration of the partial equilibrium model using forces of supply and demand was used in this chapter, and a relevant literature review was undertaken to determine whether the supply chain performance and fertilizer markets functioning can improve through policy associated actions and government interventions. However, the main disadvantage of the economic-surplus approaches as reported is that the reliability of the findings usually depends on the extent to which the underlying parameters represent local conditions [25]. Keeping this constraint in mind, economic-surplus effects were determined and augmented with a thorough assessment of the fertilizer supply chain using Tanzania as a case. Integration of related approaches may be useful in support decisions, for instance, about better allocation of resources for promoting fertilizer use and investments [2].

#### 2.1. Economic-surplus model for welfare analysis

As suggested by [26], this chapter uses fertilizer microdosing as an opportunity available for upgrading the agri-food value chains in Tanzania, targeting potential food crops [27]. It is the upgrading option that is within the reach of the weakest actor, i.e., the smallholder farmers [28]. An illustration and framework development of economic surplus (welfare and distribution) effects of the farm-level technology is of great importance for understanding the likely spillover of the new innovation [29]. Low-dimension diagrammatic analysis of expected impacts was used, based on the basic economic theory of supply and demand. In addition, a downward sloping demand curve and an upward sloping supply curve were used to characterize the domestic market for food crop produce. Thus, the choice of this methodological line comes from the fact that the economic-surplus approach requires the least information, is relatively easier to use and gives reliable results. According to [30], this method provides a relatively simple and flexible approach to understanding the value of adopting new technology by allowing for the comparison of the situations of with and without the use of the new technology. Details of the welfare impact results are portrayed in Figure 1 and are further explained in the subsequent sections.

3. Results

is attained at point e

in Figure 1 by Supply2

lower cost (P3

curve (Supply2

associated impacts.

supplied to the market (Q2

parallel to the original supply curve (Supply1

3.2. Fertilizer microdosing impact on price, yields and welfare

equal. At this point, the price is Pe1

3.1. Response of fertilizer microdosing in supply

Here, the researcher analyses the economic impacts of fertilizer microdosing on a partial equilibrium model. Figure 1 shows the market forces for a crop produce, with a standard upward sloping supply curve and downward sloping demand curve. Initially, the equilibrium

depicted situation can involve other intermediate activities of the supply chain, including transportation and storage. However, in the context of the chapter, they are hidden. For instance, better market functioning that result in favorable fertilizer prices to farmers is likely

Let us assume the scenario that smallholder farmers adopt fertilizer microdosing, which is a new farm-level technology in Tanzania. The supply curve (socially optimal supply curve) of the crop that would use fertilizer microdosing lies below the original supply curve, as shown

fertilizer microdosing may vary with the scale of production, microdose rate and price [16]. Variation of yield responses due to fertilizer use also depends on the amount of moisture in the soil [31]. Access to adequate amount of soil moisture in semi-arid areas is a necessary condition for having a positive effect of fertilizer application [32]. Thus, the assumed scenario was used as a guide for providing required insights of the fertilizer microdosing and elucidating on its

As highlighted above, soil infertility poses the greatest threat in Tanzanian agriculture, and most of the farmers do not use fertilizers on their farms. What occurs in terms of supply if innovative low input technology such as fertilizer microdosing that replenishes soil nutrients is accepted by farmers for their cash and food crop production? Agro-dealers and other fertilizer suppliers/producers may, for example, be motivated to supply this farm input. This is particularly important considering that it is a new technology that makes business possible and worth undertaking and the emergence of new policies (regulations, taxes and subsidies) that penalize and/or incentivize players of the fertilizer supply chain. It is worth noting that increasing crop production due to fertilizer use surges, given the original demand curve and the underlying motivation of doing so. Such a situation results in a lower price, Pe2, and a higher equilibrium quantity, Qe2, in the market, as given by point e2. At this new equilibrium point, consumers can buy more crop commodities/food at a lower price, resulting in a welfare gain to consumers as

to encourage fertilizer use among producers; hence improve crop production [13].

. Given the original price Pe1

1 due to the price mechanism that ensures that demand and supply is

Fostering Fertilizer Use and Welfare Distribution in Tanzania: Implications for Policy and Practice

), or the original quantity Qe1 can actually be produced at a much

) if fertilizer microdosing is adopted. It should be noted that the new supply

) due to fertilizer microdosing technology does not necessarily have to be

. The interpretation of this

http://dx.doi.org/10.5772/intechopen.78043

83

, more can actually be produced and

). Comparatively, the extent of response due to

, and the quantity traded is Qe1

Figure 1. Impacts of fertilizer microdosing in supply.

#### 2.2. The law of one price and its application

The law of one price is an economic theory that states that there is only one prevailing price for each product in a perfectly competitive market. Theoretically, price arbitrage works to dissipate price wedges between domestic and world or external market so that there is a stable tendency of domestic prices of a commodity to align with external prices [21]. In the context of this chapter, it is assumed that the movement of fertilizers from one market to the other will continue until the supply and demand forces equate the prices in both markets. It is further assumed that domestic fertilizer prices are embedded in the impact of domestic market and trade policies and actual functioning of farm-inputs markets. Therefore, the researcher has considered the law of one price as a relevant theory in underpinning the theoretical foundation of the chapter. In this regard, it has been noted that fertilizer microdosing, as an intermediary traded input, can transform the production process, given the availability of the primary factors of production, such as land, labor and capital. The value that is added through the production process, over and above the value (cost) of traded inputs (fertilizer), is value added [13]. Economic returns to the primary factors of production after the fertilizer microdosing has been applied by smallholder farmers are part and parcel of the welfare analysis presented. Moreover, additional reviews were undertaken to understand policy issues and conditions that prevent the law of one price from perfecting fertilizer supply chain as well as distribution, using Tanzania as a case.

## 3. Results

2.2. The law of one price and its application

Figure 1. Impacts of fertilizer microdosing in supply.

82 Soil Productivity Enhancement

using Tanzania as a case.

The law of one price is an economic theory that states that there is only one prevailing price for each product in a perfectly competitive market. Theoretically, price arbitrage works to dissipate price wedges between domestic and world or external market so that there is a stable tendency of domestic prices of a commodity to align with external prices [21]. In the context of this chapter, it is assumed that the movement of fertilizers from one market to the other will continue until the supply and demand forces equate the prices in both markets. It is further assumed that domestic fertilizer prices are embedded in the impact of domestic market and trade policies and actual functioning of farm-inputs markets. Therefore, the researcher has considered the law of one price as a relevant theory in underpinning the theoretical foundation of the chapter. In this regard, it has been noted that fertilizer microdosing, as an intermediary traded input, can transform the production process, given the availability of the primary factors of production, such as land, labor and capital. The value that is added through the production process, over and above the value (cost) of traded inputs (fertilizer), is value added [13]. Economic returns to the primary factors of production after the fertilizer microdosing has been applied by smallholder farmers are part and parcel of the welfare analysis presented. Moreover, additional reviews were undertaken to understand policy issues and conditions that prevent the law of one price from perfecting fertilizer supply chain as well as distribution,

#### 3.1. Response of fertilizer microdosing in supply

Here, the researcher analyses the economic impacts of fertilizer microdosing on a partial equilibrium model. Figure 1 shows the market forces for a crop produce, with a standard upward sloping supply curve and downward sloping demand curve. Initially, the equilibrium is attained at point e 1 due to the price mechanism that ensures that demand and supply is equal. At this point, the price is Pe1 , and the quantity traded is Qe1 . The interpretation of this depicted situation can involve other intermediate activities of the supply chain, including transportation and storage. However, in the context of the chapter, they are hidden. For instance, better market functioning that result in favorable fertilizer prices to farmers is likely to encourage fertilizer use among producers; hence improve crop production [13].

Let us assume the scenario that smallholder farmers adopt fertilizer microdosing, which is a new farm-level technology in Tanzania. The supply curve (socially optimal supply curve) of the crop that would use fertilizer microdosing lies below the original supply curve, as shown in Figure 1 by Supply2 . Given the original price Pe1 , more can actually be produced and supplied to the market (Q2 ), or the original quantity Qe1 can actually be produced at a much lower cost (P3 ) if fertilizer microdosing is adopted. It should be noted that the new supply curve (Supply2 ) due to fertilizer microdosing technology does not necessarily have to be parallel to the original supply curve (Supply1 ). Comparatively, the extent of response due to fertilizer microdosing may vary with the scale of production, microdose rate and price [16]. Variation of yield responses due to fertilizer use also depends on the amount of moisture in the soil [31]. Access to adequate amount of soil moisture in semi-arid areas is a necessary condition for having a positive effect of fertilizer application [32]. Thus, the assumed scenario was used as a guide for providing required insights of the fertilizer microdosing and elucidating on its associated impacts.

#### 3.2. Fertilizer microdosing impact on price, yields and welfare

As highlighted above, soil infertility poses the greatest threat in Tanzanian agriculture, and most of the farmers do not use fertilizers on their farms. What occurs in terms of supply if innovative low input technology such as fertilizer microdosing that replenishes soil nutrients is accepted by farmers for their cash and food crop production? Agro-dealers and other fertilizer suppliers/producers may, for example, be motivated to supply this farm input. This is particularly important considering that it is a new technology that makes business possible and worth undertaking and the emergence of new policies (regulations, taxes and subsidies) that penalize and/or incentivize players of the fertilizer supply chain. It is worth noting that increasing crop production due to fertilizer use surges, given the original demand curve and the underlying motivation of doing so. Such a situation results in a lower price, Pe2, and a higher equilibrium quantity, Qe2, in the market, as given by point e2. At this new equilibrium point, consumers can buy more crop commodities/food at a lower price, resulting in a welfare gain to consumers as measured in the area (B + C + D). Similarly, producers can sell more, but at a lower price, resulting in the PS of the area (E + F + G + H) minus area (B + E), which is also positive (Figure 1). The overall welfare gain due to fertilizer microdosing equals the sum of the change in the producer and the consumer surplus, which amounts to the area (C + D + F + G + H), the area between the new and old supply curves and under the demand curve, whereby, CS increased by C + D and a significant share of the welfare is favoring crop producers, presented by the area (F + G + H).

Distribution of welfare gains over producers and consumers can be influenced by varying the slope of the demand curve. Moreover, the sign does not change due to this slope change. As the demand for food is generally fairly inelastic (not perfectly), the actual scenario is likely to lie in between the two extreme cases shown. Less than one in absolute value (inelastic) estimates of elasticity of demand for food most of the time vary by type of food, and many also vary by income level [34]. Because basic food commodities such as staple foods were considered by our case, the demand will be more inelastic. Likewise, if supply is perfectly inelastic (i.e., a vertical supply curve), the equilibrium is at point xe, resulting in a lower equilibrium price and higher equilibrium quantity compared to what was analyzed before. This implies that consumers gain and producers lose. However, the overall welfare result is

(i.e., horizontal supply curve) results in equilibrium at point ze, whereby demand increases the most to Q3 as the price also falls the most to P3, and all welfare gains end up with the

A vertical supply curve is representative of the short-run, where it is generally difficult for farmers to respond to price changes, whereas the horizontal supply curve corresponds to a long-run situation, where producers of agri-food commodities can respond. However, farmers in this situation are price takers in a highly competitive market. The actual representation is likely to lie somewhere in between, with the short-run and long-run situations being closer to inelastic and more elastic, respectively. These findings imply the importance of inter-temporal effects, which seem to have been ignored in the available literature [29]. To be more specific, the overall welfare and the welfare of consumers in particular improve while that of producers declines, implying that the supply is relatively inelastic. Thus, in the short-run situation, the increase in sales from extra yields due to fertilizer microdosing could be insufficient to compensate for the price decrease on existing sales. In the long-run situation, the supply of crop produce is more elastic. In view of this, welfare gains are likely to occur, and most of the gains

3.4. Fertilizer microdosing interactions and performance of the fertilizer supply chain

may alter the anticipated impact of fertilizer microdosing, hence improved welfare.

3.4.1. Impact of fertilizer microdosing on economic returns

Some assumptions were made to arrive at the presented results. Variations of the findings could result from the influence of other factors. At this point, discussions of various impressions on the viability of fertilizer microdosing technology have been presented. The focus has been on how the impacts of fertilizer microdosing technology can be sustained by considering other interactions of fertilizer supply chain. The researcher has also identified some factors that

Development of low-input soil fertility management practice for crops is vital [35] in a wider range of cropping systems in semi-arid and sub-humid areas [12]. Fertilizer microdosing can be a better option that can be relied upon by smallholder farmers in rural areas [9]. However, before the adoption of technology is cascaded, there was a need to undertake a comprehensive economic analysis, by taking into account the associated risks [19, 36]. It was reported in sub-

consumers who benefit to the maximum extent possible, by the area under Pe1e

xeQ2Qe1, which is the area (D + G + J + K + L + M). Finally, a completely elastic

Fostering Fertilizer Use and Welfare Distribution in Tanzania: Implications for Policy and Practice

1 zeP3.

http://dx.doi.org/10.5772/intechopen.78043

85

positive under e

end up with consumers.

1

Note: Supply1 and Supply2 are the supply curves without and with fertilizer microdosing technology intervention respectively. Supply1 represents the without fertilizer microdosing scenario, whereby, consumer surplus (CS) = area A, producer surplus (PS) = area (B + E), and total surplus (TS) = area (A + B + E). Supply2 represents the with fertilizer microdosing scenario, whereby CS = area (A + B + C + D), PS = area (E + F + G + H), and TS = area (A + B + C + D + E + F + G + H). Therefore, welfare effects due to fertilizer microdosing in supply are represented by the area (C + D + F + G + H).

Welfare gains for both producers and consumers and other associated impacts such as a lower equilibrium price and higher quantity of food produced and consumed seem to be in line with other quantitative and qualitative studies undertaken on the impacts of farm-level technologies [11, 16]. The associated impacts of fertilizer microdosing can encourage fertilizer use in the perspective of low-income countries such as Tanzania, where insufficient crop productivity is a fundamental constraint. Based on Figure 1, it can also be noted that the magnitude of the impacts will depend, among others, on how crop yield (supply) effects are relative to the size of the market, which as reported earlier, varies by type of crop and farming system. Whatever the extent of the impact is, in terms of the quantity of crop produced due to fertilizer microdosing application, the size of the impact, Qe1Qe2, however, is smaller than the original size of the farmlevel technology potentials, Qe1Q2, which is due to the change in the price. Farm technologies are output-increasing in nature. The observed impacts are supported by the recent literature and ex-ante approaches of various technologies along the agri-food value chain [33].

#### 3.3. Inter-temporal welfare effects

The size of the welfare effects depends on the slope of the demand and supply curves. Let the assumption be that the extent of yield responses due to fertilizer microdosing application is the same as before, that is, the shift in the supply or demand curve is of the same distance as before, and independent of scale and/or price. The scenario considered and discussed in the context of this chapter focused on impacts on the outcomes of crop yields increase in supply. For instance, in the presence of a perfectly inelastic, that is, vertical demand curve, the new equilibrium is at point ie (same quantity, lower price), with consumers receiving all the gains from increased yields in the form of a lower price and a welfare gain of Pe1e 1 ieP3, which is equivalent to the area (B + C + E + F). In the presence of a perfectly elastic, that is, horizontal demand curve, additional crop yields in supply result in a new equilibrium at point e e , where all the gains translate into an increase in the equilibrium quantity supplied and demanded. This implies that there is no change in price. As a result, this leads to welfare gain to producers of the area (C + D + F + G + H + I).

Distribution of welfare gains over producers and consumers can be influenced by varying the slope of the demand curve. Moreover, the sign does not change due to this slope change. As the demand for food is generally fairly inelastic (not perfectly), the actual scenario is likely to lie in between the two extreme cases shown. Less than one in absolute value (inelastic) estimates of elasticity of demand for food most of the time vary by type of food, and many also vary by income level [34]. Because basic food commodities such as staple foods were considered by our case, the demand will be more inelastic. Likewise, if supply is perfectly inelastic (i.e., a vertical supply curve), the equilibrium is at point xe, resulting in a lower equilibrium price and higher equilibrium quantity compared to what was analyzed before. This implies that consumers gain and producers lose. However, the overall welfare result is positive under e 1 xeQ2Qe1, which is the area (D + G + J + K + L + M). Finally, a completely elastic (i.e., horizontal supply curve) results in equilibrium at point ze, whereby demand increases the most to Q3 as the price also falls the most to P3, and all welfare gains end up with the consumers who benefit to the maximum extent possible, by the area under Pe1e 1 zeP3.

A vertical supply curve is representative of the short-run, where it is generally difficult for farmers to respond to price changes, whereas the horizontal supply curve corresponds to a long-run situation, where producers of agri-food commodities can respond. However, farmers in this situation are price takers in a highly competitive market. The actual representation is likely to lie somewhere in between, with the short-run and long-run situations being closer to inelastic and more elastic, respectively. These findings imply the importance of inter-temporal effects, which seem to have been ignored in the available literature [29]. To be more specific, the overall welfare and the welfare of consumers in particular improve while that of producers declines, implying that the supply is relatively inelastic. Thus, in the short-run situation, the increase in sales from extra yields due to fertilizer microdosing could be insufficient to compensate for the price decrease on existing sales. In the long-run situation, the supply of crop produce is more elastic. In view of this, welfare gains are likely to occur, and most of the gains end up with consumers.

#### 3.4. Fertilizer microdosing interactions and performance of the fertilizer supply chain

Some assumptions were made to arrive at the presented results. Variations of the findings could result from the influence of other factors. At this point, discussions of various impressions on the viability of fertilizer microdosing technology have been presented. The focus has been on how the impacts of fertilizer microdosing technology can be sustained by considering other interactions of fertilizer supply chain. The researcher has also identified some factors that may alter the anticipated impact of fertilizer microdosing, hence improved welfare.

#### 3.4.1. Impact of fertilizer microdosing on economic returns

measured in the area (B + C + D). Similarly, producers can sell more, but at a lower price, resulting in the PS of the area (E + F + G + H) minus area (B + E), which is also positive (Figure 1). The overall welfare gain due to fertilizer microdosing equals the sum of the change in the producer and the consumer surplus, which amounts to the area (C + D + F + G + H), the area between the new and old supply curves and under the demand curve, whereby, CS increased by C + D and a significant share of the welfare is favoring crop producers, presented

Note: Supply1 and Supply2 are the supply curves without and with fertilizer microdosing technology intervention respectively. Supply1 represents the without fertilizer microdosing scenario, whereby, consumer surplus (CS) = area A, producer surplus (PS) = area (B + E), and total surplus (TS) = area (A + B + E). Supply2 represents the with fertilizer microdosing scenario, whereby CS = area (A + B + C + D), PS = area (E + F + G + H), and TS = area (A + B + C + D + E + F + G + H). Therefore, welfare effects due to fertilizer microdosing in

Welfare gains for both producers and consumers and other associated impacts such as a lower equilibrium price and higher quantity of food produced and consumed seem to be in line with other quantitative and qualitative studies undertaken on the impacts of farm-level technologies [11, 16]. The associated impacts of fertilizer microdosing can encourage fertilizer use in the perspective of low-income countries such as Tanzania, where insufficient crop productivity is a fundamental constraint. Based on Figure 1, it can also be noted that the magnitude of the impacts will depend, among others, on how crop yield (supply) effects are relative to the size of the market, which as reported earlier, varies by type of crop and farming system. Whatever the extent of the impact is, in terms of the quantity of crop produced due to fertilizer microdosing application, the size of the impact, Qe1Qe2, however, is smaller than the original size of the farmlevel technology potentials, Qe1Q2, which is due to the change in the price. Farm technologies are output-increasing in nature. The observed impacts are supported by the recent literature and

The size of the welfare effects depends on the slope of the demand and supply curves. Let the assumption be that the extent of yield responses due to fertilizer microdosing application is the same as before, that is, the shift in the supply or demand curve is of the same distance as before, and independent of scale and/or price. The scenario considered and discussed in the context of this chapter focused on impacts on the outcomes of crop yields increase in supply. For instance, in the presence of a perfectly inelastic, that is, vertical demand curve, the new equilibrium is at point ie (same quantity, lower price), with consumers receiving all the gains

equivalent to the area (B + C + E + F). In the presence of a perfectly elastic, that is, horizontal

all the gains translate into an increase in the equilibrium quantity supplied and demanded. This implies that there is no change in price. As a result, this leads to welfare gain to producers

1

ieP3, which is

e , where

ex-ante approaches of various technologies along the agri-food value chain [33].

from increased yields in the form of a lower price and a welfare gain of Pe1e

demand curve, additional crop yields in supply result in a new equilibrium at point e

by the area (F + G + H).

84 Soil Productivity Enhancement

supply are represented by the area (C + D + F + G + H).

3.3. Inter-temporal welfare effects

of the area (C + D + F + G + H + I).

Development of low-input soil fertility management practice for crops is vital [35] in a wider range of cropping systems in semi-arid and sub-humid areas [12]. Fertilizer microdosing can be a better option that can be relied upon by smallholder farmers in rural areas [9]. However, before the adoption of technology is cascaded, there was a need to undertake a comprehensive economic analysis, by taking into account the associated risks [19, 36]. It was reported in subhumid farming system that fertilizer microdosing (25, 50 and 75% of recommended rates) can be applied to maize farms and result in positive net return distributions [16]. Because soil moisture is a problem in semi-arid areas, fertilizer microdosing was found to be more effective if and when combined with rainwater harvesting technology. A potential economic gain was further noted from sunflower compared to other crops such as pearl millet and groundnuts. Direct impacts of fertilizer microdosing technology on yields and profit changes with the level of moisture in the soil, micro-dose rate, cropping system and general farm management practices.

to farmers due to market failures, government intervention is inevitable for incentives and welfare enhancing [8, 13, 21]. Fertilizer distribution systems need to be improved for farmers in marginal areas, as they are less likely to use fertilizer and adopt new technology than those in higher potential areas. This is also an indication that agricultural input markets, particularly those for fertilizers and seeds, require more rigorous policy actions that are location based and

Fostering Fertilizer Use and Welfare Distribution in Tanzania: Implications for Policy and Practice

http://dx.doi.org/10.5772/intechopen.78043

87

A contrasting assumption that all factors remain constant was considered in the analysis. For instance, higher crop yields due to fertilizer microdosing application result in lower prices of the crop commodity in the market, which could also increase demand elsewhere in the system and hypothetically lead to second-order impacts. To be more explicit, higher cereal yields from crops, such as maize, which are used as chicken feed, become cheaper if fertilizer is used in the farm. Nevertheless, if the supply of the chicken feed declines due to changes in price, the local chicken meat demand is likely to rise, and prices for the same will essentially rise. The idea is that local chicken are less efficient in the use of resources such as water and land compared to crops [41]. Moreover, the effects of fertilizer can be boosted by manures because when they are used together, they tend to be more effective on crop yields [42]. However, the use of manures in rural areas is limited by the availability of sufficient quantities. From this observation, it would seem that crop-

livestock integration could be further enhanced for more food and income diversification.

Although soil water is a necessary condition for realizing a significant impact of fertilizer use, improved seeds are similarly a key constituent. It should be noted that soil moisture is not a serious problem in sub-humid farming system as in semi-arid areas. In this light, fertilizer microdosing can be applied effectively in sub-humid areas and have the desired impact realized [16, 32]. Thus, there is need of introducing rainwater harvesting or irrigation technologies in semi-arid areas for fertilizer use technology to be employed and cope with climatic

context-specific [20].

3.4.4. Interactions with other commodity markets and players

Figure 2. Promoting fertilizer use and microdosing technology in Tanzania.

#### 3.4.2. Enhancing fertilizer microdosing impacts

There are costs associated with access and the application of a farm-input, and for this case, fertilizers. While the underlying causes for low fertilizer use are still debatable [37], the main notion behind fertilizer microdosing technology is to encourage farmers to use fertilizer after experiencing the associated benefits, including higher yields [9]. This farm technology is more feasible if costs associated with its use would be reduced to the level affordable by farmers [16], considering that fertilizer can account for up to 35% of the total crop production costs [8]. The government and other partners can play an important role in improving the distribution of farm inputs, rendering extension services on how best fertilizers can be applied to different cropping systems and stimulating adoption of the technology. Comparatively, the net welfare gains may be lower if there are excess costs related to fertilizer use, incurred by producers, which counteract the original shift of the supply curve [20]. However, farmers can organize themselves into strong groups and use them as platforms for collective farm-inputs procurement.

#### 3.4.3. Interactions within the fertilizer supply chain

The economic-surplus framework presented earlier cannot suffice to describe concerns emanating from the fertilizer supply chain. Measures to address issues in the fertilizer supply chain may vary significantly. For example, there could be no problem in the beginning of the supply chain, but costs and benefits may occur later in the chain and affect potential players. Fertilizer subsidy can stimulate the supply side and encourage fertilizer application to the lowest fertilizer users in the world, including Tanzania [8, 38]. However, fertilizer subsidy schemes that are convenient, transferable, and sustainable are needed for farmers who are not using fertilizers at all [39]. It should be noted that following the subsidy removal and devaluation in Tanzania, sharp declines in fertilizer use were observed [37], implying that any structural adjustment should not be detrimental to fertilizer markets in the country. Thus, improvement in inputs market functioning with a strategic investment in public goods is a potential way forward for countries such as Tanzania [24].

It should be noted that structural adjustment is the only factor that affects fertilizer prices among other factors, and fertilizer prices, however, are one of the several factors that influence fertilizer use [40]. As far as welfare distribution is concerned, fertilizer subsidies cannot only lower food prices in favor of consumers but also increase rural wages to key players of the supply chain. In general, market infrastructure, similar to other factors such as soil moisture conditions, cropping systems and extension systems, has a great role to play, and it must be considered as far as fertilizer use is concerned [20]. For example, when the fertilizer-crop price ratio is not favorable to farmers due to market failures, government intervention is inevitable for incentives and welfare enhancing [8, 13, 21]. Fertilizer distribution systems need to be improved for farmers in marginal areas, as they are less likely to use fertilizer and adopt new technology than those in higher potential areas. This is also an indication that agricultural input markets, particularly those for fertilizers and seeds, require more rigorous policy actions that are location based and context-specific [20].

#### 3.4.4. Interactions with other commodity markets and players

humid farming system that fertilizer microdosing (25, 50 and 75% of recommended rates) can be applied to maize farms and result in positive net return distributions [16]. Because soil moisture is a problem in semi-arid areas, fertilizer microdosing was found to be more effective if and when combined with rainwater harvesting technology. A potential economic gain was further noted from sunflower compared to other crops such as pearl millet and groundnuts. Direct impacts of fertilizer microdosing technology on yields and profit changes with the level of moisture in the soil, micro-dose rate, cropping system and general farm management practices.

There are costs associated with access and the application of a farm-input, and for this case, fertilizers. While the underlying causes for low fertilizer use are still debatable [37], the main notion behind fertilizer microdosing technology is to encourage farmers to use fertilizer after experiencing the associated benefits, including higher yields [9]. This farm technology is more feasible if costs associated with its use would be reduced to the level affordable by farmers [16], considering that fertilizer can account for up to 35% of the total crop production costs [8]. The government and other partners can play an important role in improving the distribution of farm inputs, rendering extension services on how best fertilizers can be applied to different cropping systems and stimulating adoption of the technology. Comparatively, the net welfare gains may be lower if there are excess costs related to fertilizer use, incurred by producers, which counteract the original shift of the supply curve [20]. However, farmers can organize themselves into strong

The economic-surplus framework presented earlier cannot suffice to describe concerns emanating from the fertilizer supply chain. Measures to address issues in the fertilizer supply chain may vary significantly. For example, there could be no problem in the beginning of the supply chain, but costs and benefits may occur later in the chain and affect potential players. Fertilizer subsidy can stimulate the supply side and encourage fertilizer application to the lowest fertilizer users in the world, including Tanzania [8, 38]. However, fertilizer subsidy schemes that are convenient, transferable, and sustainable are needed for farmers who are not using fertilizers at all [39]. It should be noted that following the subsidy removal and devaluation in Tanzania, sharp declines in fertilizer use were observed [37], implying that any structural adjustment should not be detrimental to fertilizer markets in the country. Thus, improvement in inputs market functioning with a strategic investment in public goods is a potential way

It should be noted that structural adjustment is the only factor that affects fertilizer prices among other factors, and fertilizer prices, however, are one of the several factors that influence fertilizer use [40]. As far as welfare distribution is concerned, fertilizer subsidies cannot only lower food prices in favor of consumers but also increase rural wages to key players of the supply chain. In general, market infrastructure, similar to other factors such as soil moisture conditions, cropping systems and extension systems, has a great role to play, and it must be considered as far as fertilizer use is concerned [20]. For example, when the fertilizer-crop price ratio is not favorable

groups and use them as platforms for collective farm-inputs procurement.

3.4.2. Enhancing fertilizer microdosing impacts

86 Soil Productivity Enhancement

3.4.3. Interactions within the fertilizer supply chain

forward for countries such as Tanzania [24].

A contrasting assumption that all factors remain constant was considered in the analysis. For instance, higher crop yields due to fertilizer microdosing application result in lower prices of the crop commodity in the market, which could also increase demand elsewhere in the system and hypothetically lead to second-order impacts. To be more explicit, higher cereal yields from crops, such as maize, which are used as chicken feed, become cheaper if fertilizer is used in the farm. Nevertheless, if the supply of the chicken feed declines due to changes in price, the local chicken meat demand is likely to rise, and prices for the same will essentially rise. The idea is that local chicken are less efficient in the use of resources such as water and land compared to crops [41]. Moreover, the effects of fertilizer can be boosted by manures because when they are used together, they tend to be more effective on crop yields [42]. However, the use of manures in rural areas is limited by the availability of sufficient quantities. From this observation, it would seem that croplivestock integration could be further enhanced for more food and income diversification.

Although soil water is a necessary condition for realizing a significant impact of fertilizer use, improved seeds are similarly a key constituent. It should be noted that soil moisture is not a serious problem in sub-humid farming system as in semi-arid areas. In this light, fertilizer microdosing can be applied effectively in sub-humid areas and have the desired impact realized [16, 32]. Thus, there is need of introducing rainwater harvesting or irrigation technologies in semi-arid areas for fertilizer use technology to be employed and cope with climatic

Figure 2. Promoting fertilizer use and microdosing technology in Tanzania.

variability conditions [31, 43]. In Tanzania, there is an effective locally manufactured fertilizer known as Minjingu Mazao. This fertilizer use technology can be featured in the government input subsidy programs, as experience has shown that the imported fertilizers meant for subsidizing crop production do not reach farmers. It has been reported that the imported fertilizers are being sold to unintended people, hence affecting the intended farmers [20]. Farmers are unlikely to benefit from the current yield gains as their depleted soils are nonresponsive to fertilizer application [44]. In view of this, an understanding of the possible marginal yield/income responses across different agro-ecological zones of a country is needed before investing much in soil nutrient inputs such as fertilizer microdosing. In addition, more can be done to promote fertilizer use related technologies in Tanzania and beyond (Figure 2).

what happens to the market equilibrium. Whereas the second and third columns show the price and quantity of food commodity, respectively, consumer and producer welfare are shown in the fourth and fifth columns, respectively. The overall effect of the welfare is presented in the sixth column. This scenario was assumed to occur in the market for the food commodity in question and for varying assumptions regarding demand and supply curves, providing the boundaries by rows for what might occur. The last column indicates the impact of other factors that are of influence, where possible, relaxing some of the simplifying assumptions made throughout the analyses. The following subsections present the implications for policy and in practice, and briefly highlight the aforementioned studies on the farm-level economic impacts of fertilizer

Fostering Fertilizer Use and Welfare Distribution in Tanzania: Implications for Policy and Practice

http://dx.doi.org/10.5772/intechopen.78043

89

Promoting the farm-level technology that can encourage farmers to use fertilizers in a country is a key for improving crop productivity [12]. However, there are some factors that need consideration before adopting and promoting technology such as fertilizer microdosing. First, the starting point for encouraging fertilizer use among farmers should be identified. Farmers in a country such as Tanzania are of different scales, and for this reason, fertilizer microdosing can target small-scale farmers who cultivate farms of less than a hectare. The technology is useful to farmers who do not use fertilizers, as they are motivated to use more after finding it is profitable. Because smallholder farmers are resource poor, the government can reduce the cost of the technology by appropriately subsidizing the fertilizers and improve access of fertilizers

Fertilizer microdosing can be more cost-effective if the government addresses potential market failures within the fertilizer supplier chain. [46] Suggested focusing on a holistic approach by addressing five pillars of market development and supporting conditions for effective functioning fertilizer markets. The pillars include policy, human capital, finance, market information and regulation. Crop yields can be improved with the efficient use of the technology, which goes hand in hand with the provision of opportunities for acquiring necessary knowl-

In addition, after the adoption of the fertilizer microdosing technology by farmers with or without subsidization, the technology should have positive impacts on country farming systems. Testing the effectiveness of technology for upgrading agri-food value chains in subhumid and semi-arid farming systems was important in Tanzania [12, 27]. For instance, marginal yields due to fertilizer microdosing should be high enough to motivate farmers to use fertilizers and adopt the technology. Moreover, better yields in semi-arid areas can be obtained if the fertilizer microdosing is combined with rainwater harvesting technology, par-

The second factor is related to the third one, that is, the technology contributes significantly economic returns, hence being profitable to farmers. It is envisaged that farm-level technology should increase the output. However, additional crop yield due to fertilizer microdosing is a necessary but not sufficient condition for obtaining net returns. Empirical evidence shows that

edge and skills to targeted farmers and linking them with input suppliers [20].

microdosing in Tanzania.

at the village level [16, 45].

ticularly through tied-ridges.

4.2. Promoting fertilizer microdosing technology

### 4. Discussion

#### 4.1. A synthesis

An economic theory shows that the impacts of crop yields due to fertilizer microdosing, application as a farm-level technology in supply and in terms of quantity are different from the original size of the yields. In other words, the extent of the yields obtained is influenced by the amount and the way fertilizer was applied, costs associated with fertilizers, level of food prices, size of the fertilizer market and interactions within the fertilizer supply chain and with other players and markets. It is also evident that impacts change with the slope of the demand and supply curve and consumer preference or level of the technology adoption, which play an important role in the demand size of fertilizers. If all of these influencing factors are considered, one cannot be sure of the likely impact of the fertilizer application in the context of welfare and food security.

Table 1 presents the results of the supply and demand side analyses of applying fertilizer microdosing on infertile soil that has an appropriate amount of soil moisture. It summarizes

Table 1. Overview of the impacts of increasing yields in the market as fertilizer microdosing is applied in a food commodity.

what happens to the market equilibrium. Whereas the second and third columns show the price and quantity of food commodity, respectively, consumer and producer welfare are shown in the fourth and fifth columns, respectively. The overall effect of the welfare is presented in the sixth column. This scenario was assumed to occur in the market for the food commodity in question and for varying assumptions regarding demand and supply curves, providing the boundaries by rows for what might occur. The last column indicates the impact of other factors that are of influence, where possible, relaxing some of the simplifying assumptions made throughout the analyses. The following subsections present the implications for policy and in practice, and briefly highlight the aforementioned studies on the farm-level economic impacts of fertilizer microdosing in Tanzania.

#### 4.2. Promoting fertilizer microdosing technology

variability conditions [31, 43]. In Tanzania, there is an effective locally manufactured fertilizer known as Minjingu Mazao. This fertilizer use technology can be featured in the government input subsidy programs, as experience has shown that the imported fertilizers meant for subsidizing crop production do not reach farmers. It has been reported that the imported fertilizers are being sold to unintended people, hence affecting the intended farmers [20]. Farmers are unlikely to benefit from the current yield gains as their depleted soils are nonresponsive to fertilizer application [44]. In view of this, an understanding of the possible marginal yield/income responses across different agro-ecological zones of a country is needed before investing much in soil nutrient inputs such as fertilizer microdosing. In addition, more can be done to promote fertilizer use related technologies in Tanzania and beyond (Figure 2).

An economic theory shows that the impacts of crop yields due to fertilizer microdosing, application as a farm-level technology in supply and in terms of quantity are different from the original size of the yields. In other words, the extent of the yields obtained is influenced by the amount and the way fertilizer was applied, costs associated with fertilizers, level of food prices, size of the fertilizer market and interactions within the fertilizer supply chain and with other players and markets. It is also evident that impacts change with the slope of the demand and supply curve and consumer preference or level of the technology adoption, which play an important role in the demand size of fertilizers. If all of these influencing factors are considered, one cannot be sure of the likely impact of the fertilizer application in the context of

Table 1 presents the results of the supply and demand side analyses of applying fertilizer microdosing on infertile soil that has an appropriate amount of soil moisture. It summarizes

example

Table 1. Overview of the impacts of increasing yields in the market as fertilizer microdosing is applied in a food

Price Quantity Consumers Producers Total Extent of yields increase relative to the size

–ve +ve +ve Constant +ve Interactions within the fertilizer supply

Constant +ve Constant +ve +ve Impacts may be smaller if costs associated

–ve Constant +ve Constant +ve If fertilizer use decreases, the impacts are

Factor of influence and impacts

of the fertilizer market

impacts will be lower.

with technology are high.

larger at a lower scale and price.

chain and with other players

+ve If fertilizer use involves costs, then welfare

Welfare impacts in the commodity market

4. Discussion

88 Soil Productivity Enhancement

4.1. A synthesis

welfare and food security.

Impact on market equilibrium

–ve +ve +ve –ve in

Increasing yields in supply

Perfectly elastic supply curve

Perfectly inelastic supply curve

Perfectly elastic demand curve

Perfectly inelastic demand curve

commodity.

Promoting the farm-level technology that can encourage farmers to use fertilizers in a country is a key for improving crop productivity [12]. However, there are some factors that need consideration before adopting and promoting technology such as fertilizer microdosing. First, the starting point for encouraging fertilizer use among farmers should be identified. Farmers in a country such as Tanzania are of different scales, and for this reason, fertilizer microdosing can target small-scale farmers who cultivate farms of less than a hectare. The technology is useful to farmers who do not use fertilizers, as they are motivated to use more after finding it is profitable. Because smallholder farmers are resource poor, the government can reduce the cost of the technology by appropriately subsidizing the fertilizers and improve access of fertilizers at the village level [16, 45].

Fertilizer microdosing can be more cost-effective if the government addresses potential market failures within the fertilizer supplier chain. [46] Suggested focusing on a holistic approach by addressing five pillars of market development and supporting conditions for effective functioning fertilizer markets. The pillars include policy, human capital, finance, market information and regulation. Crop yields can be improved with the efficient use of the technology, which goes hand in hand with the provision of opportunities for acquiring necessary knowledge and skills to targeted farmers and linking them with input suppliers [20].

In addition, after the adoption of the fertilizer microdosing technology by farmers with or without subsidization, the technology should have positive impacts on country farming systems. Testing the effectiveness of technology for upgrading agri-food value chains in subhumid and semi-arid farming systems was important in Tanzania [12, 27]. For instance, marginal yields due to fertilizer microdosing should be high enough to motivate farmers to use fertilizers and adopt the technology. Moreover, better yields in semi-arid areas can be obtained if the fertilizer microdosing is combined with rainwater harvesting technology, particularly through tied-ridges.

The second factor is related to the third one, that is, the technology contributes significantly economic returns, hence being profitable to farmers. It is envisaged that farm-level technology should increase the output. However, additional crop yield due to fertilizer microdosing is a necessary but not sufficient condition for obtaining net returns. Empirical evidence shows that fertilizer microdosing can have significant impacts on both yield and income in sub-humid rather than in semi-arid farming systems. Variability in soil quality, soil moisture, and fertilizer market costs influence considerably the response and distribution of crop yields and rewards [16]. This type of technology can be promoted at the country level, as it can improve agricultural growth and alleviate poverty [31, [47], Figure 1. Figure 2 presents a summary of the described factors and the way they are related to the promotion of fertilizer use and technology, in this case, fertilizer microdosing.

In this regard, policy, practice and future research tend to inform and benefit one another. If people's knowledge on the causal-impact of fertilizer microdosing is enhanced, it will enable the refinement of policies and result in better outcomes among the essential players in the

Fostering Fertilizer Use and Welfare Distribution in Tanzania: Implications for Policy and Practice

http://dx.doi.org/10.5772/intechopen.78043

91

This review has revealed how economic theory can be used to provide intuitions of the welfare effects to various players of the supply chain if fertilizer microdosing technology is adopted. The overall welfare gains to crop producers, consumers and other market agents due to fertilizer microdosing application have been found to be positive. Moreover, the size of the welfare impacts changes as the slope of the demand and supply curves change, given the crop yield responses as a result of fertilizer use and micro fertilization application. This implies the importance of inter-temporal effects in the market where farmers are considered as price takers. Other factors that seem to influence crop yield and profit responses have been highlighted. These include soil moisture, the micro-dose rate, cropping system and general farm management practices. In addition, interventions that can be undertaken by the government and other players for improving the efficiency of the fertilizer supply chain

This chapter has important policy and practice implications. The findings suggest that in a country such as Tanzania, where investment in physical infrastructures are limited, more is supposed to be done in terms of investing in functional seed and fertilizer markets, road networks, storage facilities and market information systems. Thus, a rational policy choice for a country should promote fertilizer use through embracing farm-level technologies such as fertilizer microdosing by considering the entire fertilizer supply chain. More resources can then be allocated in order to improve the welfare and living conditions of key players, particularly in rural areas. At this juncture, it could be concluded that fertilizer microdosing technology is worth adopting as it enhances agricultural growth and reduces

The author gratefully acknowledges the useful suggestions provided by anonymous reviewers. This publication is a product of the Trans-SEC project (www.trans-sec.org). The German Federal Ministry of Education and Research (BMBF) funded the project, and the German Federal Ministry for Economic Cooperation and Development (BMZ) co-financed the Trans-SEC project. The views expressed in this chapter are solely those of the author and may not, in any circumstance,

be regarded as stating an official position of the BMBF or BMZ.

fertilizer supply chain.

have been highlighted.

Acknowledgements

poverty.

5. Concluding remarks

#### 4.3. Implication for policy