Organic Fertilizer Reference Manual

In recent years, continuously increasing crop yields and improving soil nutrient utilization efficiency have become key challenges for sustainable agricultural development. As two primary types of fertilizers widely used in agricultural production, organic and chemical fertilizers exhibit complementary effects. Research indicates that Organic Fertilizers not only enhance soil texture and fertility, significantly boosting crop yields, but also improve crop quality. Moreover, organic fertilizers excel in reducing environmental pollution and protecting farmland ecosystems, particularly demonstrating advantages in conserving water resources and minimizing pesticide usage.However, we have also found that the market offers a wide variety of organic fertilizers, making their proper use sometimes challenging. The agricultural industry standard "Guidelines for the Rational Use of Organic Fertilizers" (NY/T 1868-2021) provides clear regulations on the rational use of organic fertilizers. This standard was revised from the 2010 version, with key updates including the addition of organic fertilizer sources, modifications to organic fertilizer types, and the incorporation of safe application principles and technical requirements for different types of organic fertilizers. The standard specifies terms and definitions, sources and types, properties, functions, principles and key points for rational application, application techniques for various organic fertilizers, and safety requirements. It serves as a reference manual for the use of organic fertilizers in agricultural production, with the main content as follows:

01
source
1) Organic fertilizers mainly come from plants and/or animals, including crop straw, plant residues, human and animal manure, green manure, biogas manure, peat, lignite, weathered coal, and some agricultural product processing waste.
2) When using traditional Chinese medicine residue, bone meal, earthworm castings, food grade beverage processing waste, furfural residue, aquaculture waste, etc. as organic fertilizers, safety risk assessments should be conducted. The evaluation content includes but is not limited to heavy metals, antibiotics, salts, organic pollutants, etc.
3) It is prohibited to use materials such as fly ash, steel slag, animal waste, urban garbage, sludge, and materials containing invasive alien species that pose a risk of harm to animals, plants, and farmland environment as organic fertilizers.
02
category
Including manure, straw fertilizer, green manure, compost, cake fertilizer, biogas fertilizer, soil and miscellaneous fertilizer, sea fertilizer, commercial organic fertilizer, bio organic fertilizer, composite microbial fertilizer, organic-inorganic compound fertilizer, humic acid organic fertilizer, and organic water-soluble fertilizer.

03
Property 1) Nutritious
Organic fertilizers usually contain various mineral nutrients, organic components such as sugars, amino acids, proteins, cellulose, as well as various microorganisms and their metabolites, but the nutrient content is generally low.
2) Long lasting fertilizer effect
Most of the nutrients in organic fertilizers are combined with organic carbon and need to be decomposed and transformed before they can be absorbed and utilized by crops. Nutrient release is slow and fertilizer efficiency is slow.
3) Complex composition
There are various types of organic fertilizers with complex ingredients. Some contain impurities such as materials, glass, metals, ceramics, rubber, as well as harmful substances such as heavy metals, chlorine, sodium, environmental hormones, antibiotics, pathogens, etc.
4) Different carbon to nitrogen ratios
The carbon to ammonia ratio of different types of organic fertilizers varies, resulting in significant differences in their decomposition rate, nutrient release, and fixation.
04
Function 1) Improve soil fertility
Applying organic fertilizers can increase soil organic matter, improve soil physical and chemical properties and biodiversity, enhance soil water and fertilizer retention capacity, and improve soil buffering performance.
2) Provide plant nutrition
Organic fertilizers contain both mineral nutrients and organic components, which can provide nutrients for crop growth, improve yield, and enhance quality.
3) Promote crop growth
Organic fertilizers usually contain substances that stimulate crop growth and inhibit bacteria. During the degradation process, various phenols, auxins, and hormones are produced, which can promote crop growth and improve crop stress resistance.
4) Promote material circulation
Reasonably utilizing organic fertilizer resources can promote a virtuous cycle of materials, reduce the adverse impact of Organic Waste on the environment, and at the same time, reduce the use of fertilizers, lower energy consumption, and alleviate environmental pollution.

05
Principle of Reasonable Application 1) Long term Application
Fully utilize various organic fertilizer resources, adhere to long-term application of organic fertilizers, maintain and improve soil fertility, and improve crop nutrient supply.
2) Organic inorganic combination
Organic fertilizers should be used in combination with inorganic fertilizers, with reasonable ratios, complementary strengths and weaknesses, and a balance between slow and urgent needs, fully exerting their effects to meet the needs of crop growth, achieving high and stable yields, and combining land use with land cultivation.
3) Safe application
Organic fertilizers should be treated harmlessly, with strict control over impurities and toxic substances to avoid adverse effects on crops, soil, and the ecological environment. Moderate and reasonable application, the total amount of application should be controlled in areas with high input such as facility agriculture and ecological conservation areas near water sources.

06
Key points of rational use: 1) Reasonable use for the purpose
Choose the type of organic fertilizer according to the purpose of fertilization. The main purpose of fertilizing soil is to apply organic fertilizers with high organic matter content, such as straw and cow manure. The main purpose is to provide nutrients, and organic fertilizers with high nutrient content should be applied, such as cake fertilizers, manure fertilizers, etc.
2) Reasonable application of crops
Perennial crops, crops with longer growth periods, and crops such as tubers and tubers can be treated with organic fertilizers with lower levels of maturity. Crops with shorter growth periods should be treated with organic fertilizers with higher levels of maturity.
3) Reasonable application of soil
Soil with low organic matter content should be treated with more organic fertilizers. Soil with heavy texture and poor air permeability should be treated with organic fertilizers with high degree of decay. For soils with lighter texture and poor water and fertilizer retention ability, organic fertilizers with lower maturity can be applied, or measures such as returning straw to the field and planting green manure can be taken to timely plow and press. The amount of organic fertilizers with low maturity applied to paddy fields should be controlled. Saline alkali soil with low organic matter content and poor physical and chemical properties should be treated with organic fertilizers with high maturity, and the application amount should be appropriately increased.
4) Reasonable application due to climate
In areas with low temperatures and less rainfall, it is advisable to use organic fertilizers with a higher degree of maturity. In warm and humid areas, the number and activity of microorganisms are high, and the decomposition rate of organic matter is fast. Organic fertilizers with lower maturity can be applied.
5) Adopting reasonable fertilization methods
Organic fertilizers are mainly used as base fertilizers and can be applied through methods such as spreading, strip trench application, circular trench application, radial trench application, and hole application. It is recommended to apply them evenly and plow them into the soil. Mechanical deep application is recommended. When doing top dressing, it is necessary to water it in a timely manner. Some highly decomposed compost and commercial organic fertilizers can be used as seed fertilizers and nutrient soils.

07
Key points for safe application 1) Raw material control
Strictly control the accumulation of raw materials according to the classification of organic fertilizer sources. Materials that require safety risk assessment should be comprehensively evaluated for the risk of toxic and harmful substances. It is prohibited to use materials such as garbage and sludge that may contain toxic and harmful substances and pose risks directly for farmland or the production of organic fertilizers. Recycled waste, sludge, etc. should be referred to as Agricultural Waste or agricultural sludge, and should only be used for urban and road greening. They cannot be used as organic fertilizers and cannot enter farmland. Clearly label the source, conduct regular monitoring, and conduct risk assessments.
2. Harmless treatment
During the production process of organic fertilizers, harmless treatment should be carried out to kill weeds, seeds, pathogens, parasite eggs, etc. that are harmful to crops, livestock, or human health. Plastic, glass, metal, stones, and other debris should be removed, and harmful substances such as heavy metals, chlorine, sodium, environmental hormones, antibiotics, pesticide residues, etc. should be strictly controlled to ensure the safe production of agricultural products and achieve harmless environmental hygiene. The harmless treatment of livestock and poultry manure should comply with the provisions of GB/T36195 "Technical Specification for Harmless Treatment of Livestock and Poultry Sacs and Feces". The heavy metal content in animal manure used for fertilizer production should comply with the requirements of GB/T25246 "Technical Specification for Returning Livestock and Poultry Manure to the Field".
3) Reasonable application
In general, organic materials should be fully fermented and matured through high-temperature composting before application to improve fertilizer efficiency. The maximum temperature for high-temperature composting should reach 50 ℃ and be maintained for 5-7 days. Its hygiene indicators and heavy metal content should comply with the provisions of GB/T25246 "Technical Specification for Returning Livestock and Poultry Manure to the Field". In the process of using organic fertilizers, appropriate types, times, methods, and amounts should be selected to prevent pollution caused by excessive use or concentrated application. When applying organic fertilizers with low maturity, crop roots should be avoided, and chemical fertilizers and lime should be used in combination to reduce the harm of burning seedlings and roots, pests, diseases, and weeds.