What important roles do organic fertilizers play in agricultural production?
In greenhouse production, soil must be fertilized and improved. For most land, the fundamental measure for improvement is to apply large amounts of organic fertilizer. The main roles of organic fertilizer in building soil fertility and improving soil are as follows: 1. It provides relatively comprehensive nutrients. Organic fertilizer is a complete fertilizer. It contains crops...
I. Comprehensive nutrients and lasting fertilizer effect. Organic fertilizer contains not only the major nutrient elements and trace elements essential to plants, but also rich organic nutrients such as humic acid, vitamins, auxins, antibiotics, and small-molecule compounds of organic nitrogen and phosphorus. Therefore, organic fertilizer is the most complete fertilizer. In addition, the application rate of organic fertilizer can vary over a relatively wide range, and generally it will not harm crop growth. Applying organic fertilizer not only increases the yield of the current season's crops, but generally its effect can still be seen several years later; the fertilizer effect is slow but lasting.II. Improving soil physical and chemical properties and raising soil fertility. Organic fertilizer contains large amounts of organic matter, generally about 200 g/kg. Organic matter is an important material basis of soil fertility. The main body of soil organic matter is humus, which accounts for 50%-65% of total soil organic matter. Humus is a complex organic colloid that can regulate and buffer soil pH; increase soil cation exchange capacity and improve the soil's fertilizer-retention performance; and increase soil organic matter content, which is conducive to the formation of good soil structure, especially an increase in water-stable aggregates, thereby improving soil looseness, aeration, water retention and thermal conditions, with good effects on the water, fertilizer, air and heat conditions that determine soil fertility. It is conducive to improving soil physical and chemical properties and raising soil fertility.
III. Promoting soil microbial activity. Soil microorganisms play an important role in the process of organic matter transformation and are one of the important indicators of the level of soil fertility. For example, the mineralization process of organic matter in soil, the process of making organic nitrogen and phosphorus in soil available, and the biological nitrogen fixation process of leguminous plants are all related to the action of soil microorganisms. Therefore, applying organic fertilizer, on the one hand, increases the number and populations of beneficial soil microorganisms, and on the other hand, provides good environmental conditions for soil microbial activity, significantly enhancing soil microbial activity.
IV. Maintaining and promoting soil nutrient balance. The various nutrients that plants take up from the soil can be returned to the soil through the application of organic fertilizer and in the form of plant residues. The degree of return mainly depends on whether various organic fertilizer sources are fully accumulated, reasonably composted and applied, and the rate of residue return to the field. In agricultural production, only by grasping this balance link can soil fertility rise in a spiral manner under the condition of combined application of chemical fertilizers. Therefore, applying organic fertilizer is an important measure for building soil fertility.
V. Reducing fertilizer input costs. Organic fertilizer can use local materials and be applied locally, with wide sources and low cost. By increasing the application of organic fertilizer, not only can soil fertility be built and soil nutrients increased, but the utilization rate of chemical fertilizers can also be improved, correspondingly reducing the amount of chemical fertilizer applied, thereby reducing agricultural input costs. The above characteristics and roles of organic fertilizer determine its irreplaceable important role in modern sustainable agriculture.