korean natural farming korean natural farming korean natural farming (knf) is an organic agricultural method that takes advantage of indigenous microorganisms (imo) (bacteria, fungi, nematodes, and protozoa) to produce rich soil that yields high output without the use of herbicides or pesticides. knf emphasises self-sufficiency by limiting external inputs and relying on recycled farm waste to produce biologically active inputs. while this practise has grown in popularity, scientific evidence of the benefits of knf is relatively limited. history cho han kyu, or cho han-kyu, born in 1935 in suwon, gyeonggi province, korea, started the korean natural farming method. cho completed his high school education at the age of twenty-nine while still working on his family's farm. in 1965, he went to japan for three years as an agriculture research student and studied the natural farming methods of the three teachers: miyozo yamagishi (japanese: 山岸 巳代蔵), kinshi shibata (柴田 欣志) and yasushi oinoue (大井上 康). upon his return to korea, cho combined his newly acquired knowledge with traditional korean farming methods and fermentation methods (e.g., as used in korean foods such as kimchi) and gradually invented what is now called korean natural farming. he put it into practice by setting up a "labour-saving abundant harvesting study group" in 1966. he opened the natural farming life school and research farm in goesan county, north chungcheong province, in 1995. from 1992 onwards, cho contributed to the 21-part article in the "modern agriculture" magazine (japanese: 現代農業), published in japan. hoon park brought knf to hawaii from south korea where, as a missionary, he noticed knf commercial piggeries with virtually no odour. in 2008, he renamed his natural farming school and lab to "cho han-kyu global village natural farming research institute", or janong natural farming institute. principles the fundamental insight of knf is to strengthen the biological functions of each aspect of plant growth in order to increase the productivity and nutrition. biology thereby reduces or eliminates the need for chemical interventions, whether to protect against predation or competition with other plants. for example, the metabolism of indigenous microorganisms (imos) produces complete proteins, while insects prefer incomplete proteins. . knf avoids the use of manure, thereby reducing the chance of transferring pathogens from the manure back into the food production chain, although in nitrogen-poor conditions adding manure can increase yield. use the nutrients contained within the seeds use indigenous microorganisms (imo) maximize inborn potential with fewer inputs avoid commercial fertilizers avoid tilling no use of livestock-waste indigenous microorganisms potential benefits include increased rates of soil organic matter decomposition, increases in nutrient availability, improved plant yield, a reduction in pathogenic microorganisms and an increase in plant defences. knf uses aerobic microorganisms. beneficial microorganisms can significantly suppress fungal pathogen activity in crops of mildly susceptible rhododendron cultivars, but highly susceptible cultivars may even be harmed. imos can reduce initial yield losses when transitioning from conventional to organic farming, by accelerating soil recovery. soils depleted by the use of insecticides, fungicides and herbicides may have reduced soil microorganisms. a healthy rhizosphere contains some 7 million microorganisms per hectare. its rhizome contains diverse species and a relatively small concentration of microorganisms that damage plant life and a relatively large amount of plant secretions. mould constitutes 70–75%, bacteria 20–25% and small animals the rest. the microorganisms contain approximately 70 kg of carbon and 11 kg of nitrogen, similar to the amount of nitrogen typically applied as fertilizer. examples of microorganism reproduction minutes per generationgenerations per daytemperatureproliferation per day lactic acid bacteria3838252.5x10¹¹ coliform bacillus1885373x10²³ free nitrogen fixation bacteria11013258x103 hay bacillus3146306x1013 photosynthetic bacteria14410301x103 yeast fungus12012304x103 soil nutrient cycling nutrients are taken up and deposited in a natural cycle unless disrupted by human intervention. as plants decay, "detrital" nitrogen and phosphorus are returned to the soil. soil fungus and bacteria absorb those nutrients. the fungus and bacteria are consumed by fungal and bacterial-feeding nematodes, respectively. those nematodes are in turn consumed by omnivorous predatory nematodes. at each stage, some inorganic nitrogen and phosphorus is returned to the soil and is absorbed by the plant. bacteria and fungi three types of bacteria common in knf include lactic acid bacteria, purple bacteria, bacillus subtilis and yeast. mycorrhizae mycorrhizae are “fungus roots”, a mutualistic association between a fungus (myco) such as aspergillus oryzae and plant roots (rhiza). this provides an interface between plants and soil. the fungus grows into the roots of crops and out into the soil, increasing the root system many thousand-fold. the fungi use their enzymes to convert soil nutrients into a form that crops can use and turn plant carbohydrates into soil amendments, “sequestering” carbon. miles of mycorrhizae can be found in a single ounce of soil. mycorrhizal soil inoculation increases soil carbon accumulation by depositing glomalin, which increases soil structure by binding organic matter to mineral particles. glomalin gives soil its tilth (texture), buoyancy and water absorption ability. biochar (charcoal) shelters mycorrhizae in myriad, tiny holes. other mycorrhizal impacts include enhanced water uptake, reduced water needs (increased drought resistance), increased pathogen resistance and overall increased plant vigor. nematodes nematodes such as the reniform nematode rotylenchulus reniformis are often seen as harmful to agriculture and are a frequent target of pesticides. however, knf asserts that 99% of nematodes are beneficial and even consume parasitic nematodes. herbivorous, fungivorous, bacterivorous and omnivorous nematodes are important participants in nutrient cycling. tillage and other soil management practices affect nematode variety and populations. conservation tillage benefits bacterivores and fungivores, but the structure index (si) is not different between cover cropping and fallow fields. in one experiment, simple no-till and strip-till failed to show increases in soil food web structure over two years but did after six years. in the greenhouse, green manure increased omnivorous and predatory populations. strip-till of sunn hemp cover crop followed by mulching soil surface periodically with sunn hemp residues enhanced si within 2 cropping cycles. stages of plant development knf posits three primary stages of plant growth. each stage requires a different balance of nutrients. vegetative growth in the vegetative growth phase, the plant extends its roots, branches and foliage. the key nutrient in this stage is nitrogen. knf prefers the use of a preparation of fish amino acids for this phase. flowering/reproduction after the plant has reached sufficient size, the plant diverts its energy into making flowers to attract pollinators. the key nutrients in this stage are calcium and phosphorus. knf prefers the use of a preparation of fermented plant juice and other amendments for this phase. fruiting after flowering is complete, the plant shifts its focus to bringing its fruit to full ripeness. calcium enhances the size and sweetness of the plant and its fruit. knf prefers the use of a preparation of pulverized eggshells in brv (brown rice vinegar) for this phase. amendments knf uses a variety of amendments either to directly enhance plant growth or to enhance imo proliferation. note: all water first stands in an open container for several days to allow chlorine and any other volatiles to escape. amendments are diluted 500–1000:1 for use. fermented items knf ferments a variety of materials for use in different contexts. fermented products are produced in glass or ceramic (not metal or plastic) containers filled to 2/3-3/4 of their capacity and covered with porous paper or cloth. brown sugar or jaggery (bs/j) is used as a fermentation agent. knf does not use molasses, which contains excess moisture. fermentation takes place in a dark, cool area and the results must be refrigerated or kept in a cool environment. the ideal temperature for fermentation is 23–25 °c (73–77 °f). fermented fruit juice fermented fruit juice (ffj) uses the juice of locally-grown fruits with relatively high sugar content, such as banana, papaya, mango, grape, melon or apple. ffj from grapes and/or citrus should be used only on crops of grapes or citrus, respectively. ffj is diced or mashed fruit diluted 0.65:1 with water and 1:1 with bs/j, fermented for 4–8 days with periodic stirring. fermented plant juice fermented plant juice (fpj) allows material produced by successful plants to be reincorporated into other plants. when bs/j is combined with plant material, plant juices are secreted via osmosis and microbes present on the plant material begin to break down the sugars and create ethanol. this weak alcoholic solution extracts plant components including chlorophyll. fpj uses young sections of a fast-growing weeds that flourish in/around the fields that are undergoing cultivation or the plants to be cultivated there, harvested in the morning after a dry day. rain may wash away microbes from the plant, inhibiting proper fermentation, and before sunrise, plant chemistry is more ideal for fpj. purslane and comfrey have proven effective choices, as have dropwort, mugwort, watercress, angelica, bamboo shoots, sweetpotatoe vines, beans, pumpkin, and seaweeds. layers of chopped plants alternate in 1-inch layers with bs/j. pressure applied after each layer appropriately minimizes the amount of air. after 7–10 days, liquid extraction from the mixture has peaked and the remaining solids must be strained from the result. fpj is not helpful in the presence of high precipitation and/or high nitrogen conditions. fish amino acids fish amino acids (faa) provide nitrogen to enhance vegetative growth. fish heads, guts, bones, etc. (preferably tuna or other blue-backed fish), crushed to separate flesh and bone are fermented with an equal amount of bs/j. two to three teaspoons of imo3 can dissolve any fat that develops on the surface. the top layer is a mixture of bs/j, imo4, ohn, mineral a and rice straw. fermentation generally takes 7–10 days. kohol amino acid kohol amino acid (kaa) are made from the kohol or golden apple snail, pomacea canaliculataor is an introduced pest in the philippines that proliferates in rice paddies and consumes young rice seedlings. proper water management and transplanting the rice seedlings can mitigate its effects. due to its high protein content (12%), kohol may be used to manufacture a crop amendment referred to as kohol amino acid (kaa), as an alternative to faa in inland regions who do not have access to affordable fish materials. the kohol has to be removed from the rice paddy anyway. the kohol are fermented in the usual way by diluting with bs/j and water and adding imo3, after boiling to kill the animals and separate them from their shells. fermentation takes 7–10 days after which remaining solids are removed. during storage, additional bs/j is added to nourish the imo. maltose knf maltose is made from sprouted barley (malt). the sprouts are then crushed and repeatedly soaked and separated from water. the malt then rises to the surface and is separated from the water and fermented. oriental herbal nutrients oriental herbal nutrients (ohn) are fermented from unwashed, dried angelica gigas, cinnamon bark and licorice root glycyrrhiza glabra along with garlic and ginger. preparation and storage while each herb is fermented separately, the results are combined for use, at the ratio of 2 parts angelica to 1 part of each of the other four. the material can be fermented 5 times, removing 2/3 of the liquid after each cycle. ginger and garlic must be crushed (not ground) to aid fermentation. one herb is mixed with rice wine in equal parts and fermented for 1–2 days. bs/j equal to the amount of herb is added and the mix fermented for 5–7 days. soju, vodka or another distilled (30~35%) alcohol equal to half of the mixture is added and the mix is fermented for 14 days. fermented mixed compost fermented mixed compost (fmc) is the result of applying knf techniques to turn familiar compost materials into imo-rich material with readily available nutrients. in the late fall, bacterial activity subsides and fermenting microbes flourish, producing sugar and the best environment for fmc. a shady, sheltered location with good drainage on an earthen floor provides the best environment. the minimum batch size is 500 kg, to optimize fermentation. fmc includes at least one item each from the garden (fallen leaves or fruits), rice field (rice bran, straw), field litter from oil cake or bean cake and ocean (seaweed, fish waste). the bulk of the material is high-protein animal matter with added plant matter. during fermentation, periodic turning is used to keep temperatures below 50 °c. excess heat or moisture can produce an unpleasant/foul smell, signaling that the batch is ruined. wet compost mixes imo4 with oil cake,