The technology of substituting organic fertilizer for chemical fertilizer in major crops →

Replacing chemical fertilizers with Organic Fertilizers is a practical necessity for achieving the resource utilization of organic waste from farming and improving the rural ecological environment. It is also an important technical approach to reduce the amount of chemical fertilizers while enhancing their efficiency, improving the quality of farmland, and enhancing the quality and efficiency of agricultural products. Furthermore, it is a significant measure to promote the green and high-quality development of agriculture.
Basic Principles
(1) Adhere to the combination of organic and inorganic fertilizers. Taking into comprehensive consideration the nutrient requirements of crops and the current status of regional soil fertility, guide farmers to increase the application of organic fertilizers, and combine them with new types of fertilizers such as formulated fertilizers and slow-release fertilizers, to leverage the synergistic effect between organic and inorganic nutrients.
(2) Adhere to the synergy of reducing quantity and increasing efficiency. Appropriately increase the input of organic fertilizers, optimize the fertilization structure, utilize organic nutrients to replace some chemical fertilizer nutrients, promote the reduction of chemical fertilizer quantity and increase efficiency, and enhance the quality of cultivated land and achieve green, high-quality, and efficient agriculture.
(III) Adhere to the planting and breeding cycle. By establishing mechanisms, creating models, expanding markets, and smoothing the cycle, we will break through the bottlenecks in the planting and breeding cycle, form a development model of integrated planting and breeding, where farmers, service organizations, and planting entities are closely connected, and promote the on-site and nearby utilization of manure for returning to the field, thus promoting the green and high-quality development of agriculture.
Technology of substituting organic fertilizer for chemical fertilizer in major crops
(1) Major grain crops
It is recommended to use new types of fertilizers such as crop-specific formula fertilizers, slow-release fertilizers, and organic-inorganic compound fertilizers; and to guide farmers to increase the application of organic fertilizers such as decomposed compost and organic water-soluble fertilizers to replace some chemical fertilizers.
Organic fertilizers such as decomposed compost and commercial organic fertilizers are mainly applied as base fertilizers in autumn or before wheat sowing; organic water-soluble fertilizers are mostly used as topdressing during the later stages of crop growth.
The application rate of compost is generally 1 to 2 tons per mu; the application rate of commercial organic fertilizer is generally 0.2 to 0.5 tons per mu, with a reduction of 10% to 20% in chemical fertilizer application depending on the location and crop.
Due to the slow nutrient release of organic fertilizers, the amount of chemical fertilizers to be replaced or reduced should be scientifically determined based on the target yield of major food crops, soil nutrient content, and characteristics of organic fertilizers. For plots that have not been applied with organic fertilizers for a long time, a significant reduction in chemical fertilizer application in the same year should be avoided.
(II) Main fruit tree crops
It is recommended to apply new types of fertilizers such as organic-inorganic compound fertilizers, organic water-soluble fertilizers, and specialized formula fertilizers; to develop orchard grass planting and natural grass growth according to local conditions, and to scientifically apply organic fertilizers such as decomposed compost to replace and reduce the use of some chemical fertilizers.
Orchard green manure should primarily be cultivated through surface mulching, allowing for one-year planting with multi-year utilization without the need for mowing or plowing. Arid and barren orchards are suitable for planting high drought-resistant and low water-consuming legume green manure crops such as hairy vetch and smooth vetch. Orchards with good irrigation can also plant grass family and cruciferous green manure crops such as tall fescue and Violet daylily.
During the 1-5 years of green manure cover cultivation in orchards, the yield of fresh green manure grass should be 1.5-3 tons per mu. The amount of chemical fertilizer that can be reduced by substitution can be increased year by year, usually by 10%-30%.
Promote the use of livestock manure, straw, and other materials for on-site composting and returning to the field. The composted materials should be mainly used as base fertilizer before winter or after fruit picking.
The application rate of compost is generally 2 to 3 tons per mu; the application rate of commercial organic fertilizer is generally 0.4 to 0.8 tons per mu, with a substitution and reduction of 15% to 25% of chemical fertilizer application depending on the specific conditions.
Due to the varying fertilizer efficiencies of different organic fertilizers, the amount of chemical fertilizer to be substituted or reduced should be scientifically determined based on the target yield of the orchard and soil nutrient content. For newly established orchards, the application of organic fertilizer should be appropriately increased, while avoiding a significant reduction in chemical fertilizer application in the same year.
(III) Main vegetable crops
It is recommended to apply new types of fertilizers such as organic water-soluble fertilizers, bio-organic fertilizers, and organic-inorganic compound fertilizers. Depending on the soil and crops, organic fertilizers such as decomposed compost and microbial fertilizers should be increased to replace some of the reduced chemical fertilizers.
Organic water-soluble fertilizers have fast nutrient absorption and high fertilizer efficiency, and are mainly applied as topdressing through methods such as integrated water and fertilizer management and foliar spraying. Compared to conventional fertilization methods, they can reduce the amount of topdressing by more than 30%.
Organic fertilizers such as decomposed compost are primarily applied as base fertilizer before sowing. Methods such as uniform spreading and strip trenching can be used, and the fertilizer should be plowed into the soil.
The application rate of compost is generally 2 to 5 tons per mu; the application rate of commercial organic fertilizer is generally 0.4 to 0.8 tons per mu, with a reduction of 10% to 25% in chemical fertilizer application depending on the location and crop.
Due to the varying fertilizer efficiencies of different organic fertilizers, the amount of chemical fertilizer to be replaced or reduced should be determined based on the target yield of different vegetable crops and soil nutrient content. For vegetable fields that have not been applied with organic fertilizers for a long time or newly built vegetable greenhouses, the amount of organic fertilizer should be appropriately increased, and a significant reduction in chemical fertilizer application in the same year should be avoided.
Quality requirements and application techniques for major organic fertilizers
(1) Matured compost
Using livestock manure, straw, and other materials as the main raw materials, under artificial control conditions (such as moisture, carbon-to-nitrogen ratio, and ventilation), organic matter is degraded through microbial fermentation, resulting in a product suitable for land use. The quality of this product should comply with requirements such as the "Technical Specifications for Livestock Manure Composting" (NY/T3442-2019).
Mix livestock and poultry manure evenly with auxiliary materials, controlling the moisture content to be 45% to 65%, the carbon-to-nitrogen ratio to be 20:1 to 40:1, and the pH to be 5.5 to 9.0. Inoculate with organic material decomposer at 0.1% to 0.2% of the compost material mass, regulate the temperature of the pile, and fully decompose it.
Before returning compost to the field, it must undergo harmless treatment and composting according to the "Technical Specifications for Harmless Treatment of Livestock and Poultry Manure" (GB/T36195-2018). Additionally, guided by standards such as the "Technical Specifications for Returning Livestock and Poultry Manure to the Field" (GB/T25246-2010), the quantity, timing, and method of compost application should be scientifically and reasonably determined to avoid excessive and overly concentrated application.
Decomposed compost can be applied using fertilization methods such as mechanical spreading, strip trenching, and hole application, and then plowed into the soil.
(II) Commercial organic fertilizer
The organic carbon-containing materials, primarily sourced from plants and/or animals and subjected to fermentation and composting, serve to enhance soil fertility, provide plant nutrients, and improve crop quality. Their quality should comply with the requirements outlined in "Organic Fertilizers" (NY/T525-2021).
It can be used as a base fertilizer in combination with chemical fertilizers, and applied intensively through methods such as hole application, furrow application, and circular fertilization. When applying, a certain distance should be maintained from the plant roots, and it should be applied in furrows between two rows of crops or in holes between plants.
When used as seed fertilizer, it can be applied in various ways such as strip application, spot application, and hole application. It can be mixed with chemical fertilizers and applied to the soil during mechanical sowing, avoiding simultaneous application with alkaline fertilizers.
(III) Bio-organic fertilizer
A type of fertilizer that combines the effects of microbial fertilizer and organic fertilizer, made from a combination of specific functional microorganisms and organic materials primarily sourced from animal and plant residues (such as livestock manure, crop straw, etc.) and subjected to harmless treatment and composting. Its quality should comply with the requirements of "Bio-organic Fertilizer" (NY884-2012).
Bio-organic fertilizer can increase the supply of nutrients required by plants or promote plant growth and improve yield through the life activities of the microorganisms it contains. It can be used as a base fertilizer in combination with chemical fertilizers, appropriately reducing the amount of chemical fertilizer applied.
It can be applied in a concentrated manner using methods such as broadcast application, hole application, and furrow application, and the soil should be covered in a timely manner. Before application, it is necessary to pay attention to information such as production date, application rate, and application method, and to apply it within the validity period.
Avoid application under high temperature and drought conditions. After application, avoid prolonged direct sunlight exposure. It is not recommended to mix with fungicidal pesticides.
(IV) Organic-inorganic compound fertilizer
The quality of compound fertilizers containing a certain amount of organic fertilizer shall comply with the requirements of "Organic-Inorganic Compound Fertilizers" (GB/T18877-2020).
Applying organic-inorganic compound fertilizers to major cash crops can not only leverage the rapid and abundant supply of inorganic fertilizers, but also harness the benefits of organic components in enhancing soil organic matter content and enriching soil fertility. At the same time, it can replace or reduce the application of some chemical fertilizers. Organic-inorganic compound fertilizers with high phosphorus and potassium content can be used as base fertilizers instead of ordinary compound fertilizers. High-nitrogen organic-inorganic compound fertilizers can be used as topdressing.
Organic-inorganic compound fertilizers can be applied by methods such as strip application, spot application, and hole application, and direct contact with seeds should be avoided.
(V) Organic water-soluble fertilizer
Using organic resources such as free amino acids, humic acid, algal extract, chitosan, polyglutamic acid, polyaspartic acid, molasses, low-value fish, and fermentation degradation products as the main raw materials, through physical, chemical, and/or biological processes, and by adding appropriate amounts of macro-, meso-, and/or trace elements required for plant growth, liquid or solid water-soluble fertilizers containing biostimulants are processed. The quality of these fertilizers should comply with the requirements of the "General Requirements for Organic Water-Soluble Fertilizers" (NY/T3831-2021).
Organic water-soluble fertilizers are easily soluble in water, with fast nutrient absorption and high fertilizer efficiency. They are mainly applied by methods such as foliar spraying, seed soaking and root dipping, and integrated water and fertilizer management.
When applying fertilizer, the concentration of the solution should be strictly controlled to avoid fertilizer damage caused by excessively high concentration or reduced fertilizer efficiency caused by excessively low concentration.
Foliar spraying should be conducted during the critical growth stages of crops; for integrated water and fertilizer application, the content of water-insoluble substances should be controlled according to the type of irrigation system, and attention should be paid to the reaction between fertilizer and irrigation water as well as the compatibility of fertilizer mixing to avoid clogging of irrigation emitters.
(VI) Agricultural biogas fertilizer
Using organic wastes such as livestock manure and straw as raw materials, solid and liquid fertilizers produced through full anaerobic fermentation, namely biogas residue fertilizer and biogas slurry fertilizer, the quality of agricultural biogas fertilizer should comply with the requirements of "Agricultural Biogas Slurry" (GB/T40750-2021), "Biogas Fertilizer" (NY/T2596-2022), and other standards.
Biogas residue fertilizer is primarily used as a base fertilizer, applied by methods such as broadcasting, strip fertilization, and hole fertilization, and then plowed into the soil. Biogas slurry fertilizer can be used as both base and topdressing fertilizers. After being diluted and filtered, it can be applied by methods such as sprinkler irrigation, drip irrigation, and foliar spraying.
Biogas fertilizer should be scientifically applied after undergoing harmless and stabilization treatments, and long-term excessive application should be avoided.
After sufficient aeration, biogas fertilizer can be applied according to the growth stage nodes of crops that require fertilizer and water. The application amount should be calculated and determined based on the crops, soil nutrients, soil moisture, and other conditions.