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 emphasizes self-sufficiency by limiting external inputs and relying on recycled farm waste to produce biologically active inputs. While this practice has grown in popularity, scientific evidence of the benefits of KNF is relatively limited.Keli'ikuli, A. (2018). Unraveling the Mystery of the Natural Farming System (Korean): Isolation of Bacteria and Determining the Effects on Growth [Master's thesis, University of Hawai'i at Mānoa].
History Hankyu Cho (1935–2025), born in 1935 in Suwon, Gyeonggi Province, Korea, started the Korean Natural Farming method. He started to farm since he was 13 years old from his hometown Suwon. However, he felt it is not enough of learning so he decided to go to Suwon Agricultural High School to study more. Cho completed his high school education at the age of twenty-nine while still working on his family's farm. He went to high school at the late age due to the Korean War. He gave up on going to college because it was different from the farming methods he had learned from the nature, and wanted to learn together with like-minded friends. In 1961, he started a rural development movement with Byeong-gyu Kim led by Geongwoo Lee in Hyangnam, Hwaseong, Gyeonggi-do, South Korea, and developed a farm in the Sanan (Yamagishi) style. To ensure the continuation of their collaboration, these three people held a joint wedding ceremony with their respective younger sisters. 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 (), Kinshi Shibata (柴田 欣志) and Yasushi Oinoue (大井上 康).Cho Han-kyu and Cho Juyong, "Natural Farming" (187 pages), a textbook used at Cho Han-kyu's natural farming seminar held in Hilo, Hawaii, USA, in January 2016.
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.Cho Han-kyu's Profile, as shown before his seminar in Japan (in Japanese) He established the Evergreen Agricultural Association and became the president of the Korean Natural Farming Association in 1989.
From 1992 onward, Cho contributed to the 21-part article in the "Modern Agriculture" magazine (), published in Japan. He also published The Natural Farming of Hankyu Cho in 1992 which was translated in several different languages. Cho published Saving Indigenous Microorganisms (Japanese edition) in 1993 and "Soil Must Live for the Table to Thrive" in 1994. He published Korean Natural Farming: Indigenous Microorganisms and Vital Power of Crop/Livestock by Hankyu Cho& Atsushi Koyama (English edition) in 1997. To spread Korean Natural Farming (KNF) overseas, he travelled to around 30 countries and people there call him "Master Cho". Cho published more two books afterward, All About Heavenly Green Juice (Japanese edition) in 1998 and Making Natural Farming Materials (Korean edition) in 2000. He spend his whole life on spearding his knowledge and help farmers. Hoon Park brought KNF to Hawaii from South Korea where, as a missionary, he noticed KNF commercial piggeries with virtually no odour.
Based on Cho's activities, he received many awards and honors.
Awarded the Sektap Industrial Medal, recipient of the Korea-Japan International Environmental Award (The Asian Environmental Awards), jointly established by the Chosun Ilbo and Japan's Mainishi Shimbun, awarded the Zhengzhou Friendship Award (China), the Jilin Province Friendship Award (China), the Excellent Foreign Expert Award by the Yanbian Korean Autonomous Prefecture (China) and Recopient The Dosan Education Award.
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.
In 2019, Cho went to Perris (CA), Williams (OR), and Rochester (WA), the United States to meet his students and discuss about KNF.
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 defenses. 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. Mold 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 generation Generations per day Temperature Proliferation per day Lactic acid bacteria 38 38 25 2.5 × 1011 Coliform bacillus 18 85 37 3 × 1023 Free nitrogen fixation bacteria 110 13 25 8 × 103 Hay bacillus 31 46 30 6 × 1013 Photosynthetic bacteria 144 10 30 1 × 103 Yeast fungus 120 12 30 4 × 103
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 – 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 .
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