In short, organic fertilizer refers to organic materials such as animal and plant residues, excrement or biological waste, which are made through microbial action or natural fermentation process, contain a large amount of organic matter, and can provide comprehensive nutrition for plants.
Organic fertilizer comes from nature, which can not only provide rich nutrients for the soil, but also improve soil structure and promote soil microbial activity, thereby building a healthier and more sustainable ecosystem. Below, we will elaborate on how to use organic fertilizer efficiently from five aspects: definition and classification of organic fertilizer, selection, application time, application method, and precautions.
- Definition and classification of organic fertilizer
Organic fertilizer is different from chemically synthesized inorganic fertilizer. It focuses more on restoring and maintaining the ecological balance of the soil, promoting the activity of soil microorganisms, and improving the soil’s ability to retain water and fertilizer. According to the source of raw materials, organic fertilizers can be divided into the following categories:
Animal-derived organic fertilizers: mainly include livestock and poultry manure (such as cow dung, pig manure, chicken manure, etc.), fish meal, bone meal, etc. These fertilizers are rich in nitrogen, phosphorus, potassium and other macroelements, as well as a variety of trace elements and growth hormones, which are extremely beneficial to crop growth.
Plant-based organic fertilizers: such as crop straw, green manure, fallen leaves, sawdust, etc. These materials can be converted into humus-rich organic fertilizers through composting, increase the organic matter content in the soil, and improve the soil structure.
Microbial fertilizers: including bacterial fertilizers, biological organic fertilizers, etc., which convert organic matter into a form that can be directly absorbed and utilized by crops through the action of specific microorganisms, while enhancing the stress resistance and quality of crops.
Mixed organic fertilizers: fertilizers made by mixing the above-mentioned raw materials in a certain proportion, aiming to combine the advantages of various fertilizers and provide more comprehensive nutritional support.
- Choose the right organic fertilizer
There are many types of organic fertilizers, including animal manure (such as cow dung, sheep dung), plant residues (such as straw, green manure), compost, cake fertilizer, etc. Different types of organic fertilizers have different nutritional components, release rates and applicable crops.
The selection of suitable organic fertilizers requires comprehensive consideration based on crop needs, soil conditions and climatic conditions. For example, for acidic soils, an appropriate amount of lime-based organic fertilizers (such as wood ash) can be added to neutralize the acidity; for nitrogen-loving crops such as leafy vegetables, bean cake fertilizers with a high nitrogen content or thoroughly decomposed animal manure can be selected; and for orchards or vegetable gardens that need to improve soil structure, compost is an ideal choice because it can increase the content of soil organic matter and improve the soil aggregate structure. In addition, ensure that the source of organic fertilizers is reliable and avoid using fertilizers containing heavy metals or other harmful substances.
- Grasp the timing of application
The timing of applying organic fertilizers is crucial. Generally speaking, base fertilizers should be applied before crop planting or before sowing and transplanting. At this time, the soil temperature is low, which is convenient for the full decomposition of fertilizer organic matter and provides continuous nutritional support for crop growth.
Topdressing should be flexibly arranged according to the crop growth cycle and nutrient requirements, such as supplementing during the vigorous growth period of crops or the key growth period to meet the needs of rapid crop growth. For crops with a long growth period, such as trees and forests, organic fertilizers can also be applied in time during the growing season.
In addition, spring and autumn are good times for soil improvement and fertilization. Applying organic fertilizers at this time can effectively improve the soil environment and lay a good foundation for crop growth in the next year; and applying organic fertilizers in winter can also help increase soil temperature and protect crop roots from frost damage.
- Scientific application methods
Deep application and covering: For solid organic fertilizers, such as compost and cake fertilizer, it is recommended to use deep application and covering, that is, apply fertilizers into the deep soil layer and then cover the soil to reduce nutrient loss and improve fertilizer utilization.
Covering and returning to the field: Crop residues such as crop straw and green manure can be directly turned over and returned to the field, directly covered on the surface, and converted into soil organic matter through natural decomposition. This method is both environmentally friendly and economical, but it is necessary to control the thickness of the cover to avoid affecting crop growth.
Furrow or hole application: For crops with high economic value such as fruit trees and vegetables, deep application methods such as furrow or hole application can be used to apply fertilizer directly into the root distribution layer to promote root absorption.
Tillage after spreading: Before planting, organic fertilizer can be evenly spread on the surface, and then the fertilizer can be mixed with the soil by tillage to evenly distribute the fertilizer in the tillage layer to avoid local over-concentration or over-dilute.
Liquid organic fertilizer: For liquid organic fertilizer, such as biogas slurry, humic acid, etc., it can be applied through irrigation system or foliar spraying to quickly supplement the nutrients required by crops.
Combined irrigation: In arid areas or when the soil is insufficiently moist, organic fertilizer can be dissolved in water and applied through drip irrigation, sprinkler irrigation, etc., which not only supplements soil moisture but also promotes the dissolution and absorption of fertilizer.
- Precautions
When applying organic fertilizer, soil conditions, crop needs and local resource conditions should be comprehensively considered. For example, although livestock and poultry manure is rich in nitrogen, phosphorus, potassium and trace elements, it is necessary to pay attention to the heavy metals and pathogens it may contain, and it must be treated harmlessly before use; while crop straw and green manure are more suitable for improving soil structure and increasing soil organic matter content. The following are some common precautions:
Avoid excessive application: Although organic fertilizers are beneficial to soil and crops, excessive application may also lead to excess nutrients, affect crop growth, and even cause environmental pollution. Therefore, the application amount should be reasonably determined based on soil test results and crop needs.
Fully decomposed: Undecomposed organic fertilizers may contain harmful substances such as pathogens and insect eggs, and direct application will harm crop health. Therefore, it is necessary to ensure that the fertilizer is fully decomposed before use.
Combined application: Organic fertilizers and chemical fertilizers have their own advantages and disadvantages. Reasonable combination can complement each other and improve fertilization effects. For example, organic fertilizers are applied in base fertilizers, and appropriate amounts of fertilizers are applied according to crop growth conditions.
Combining fertilization with irrigation: Irrigation should be carried out in time after fertilization to promote fertilizer dissolution and root absorption. However, flooding should be avoided to prevent nutrient loss.
In short, the effect of organic fertilizer use is affected by many factors, including fertilizer type, application time, application method, soil and climate conditions. Scientific and reasonable application of organic fertilizer can not only increase crop yield and quality, but also improve soil environment and promote sustainable agricultural development. Therefore, mastering the efficient use of organic fertilizer technology is of great significance to modern agricultural production.
