The role of organic fertilizers in agricultural production
1. Supply crop nutrients and active substances and increase the intensity of photosynthesis. In the process of continuous mineralization of organic fertilizers in the soil, it can supply a variety of nutrients necessary for crops for a long time, and can also supply various active substances, such as amino acids. , RNA, humic acid and various enzymes. Especially in livestock and poultry manure, the enzyme activity is particularly high, which is several tens to hundreds times more than the soil enzyme activity. It not only can replenish plants, but also stimulate the growth of crops. It can also enhance soil microbial activity and improve the effectiveness of soil nutrients. In the process of decomposition of organic fertilizers, a large amount of CO2 is produced for the assimilation of carbon by the crops. The photosynthesis intensity of the plants is within a certain range of CO2, and increases linearly with the increase of CO2. According to experiments in places like Beijing and Fujian, increasing the CO2 concentration can increase crop production by more than 10%. Organic fertilizers are rich in carbon sources and are important for promoting crop growth and increasing yield. 2. Enhancing soil fertility Soil organic matter is one of the main indicators of fertility level measurement, is the material basis of soil fertility, and is the material source for recharging and renewing soil organic matter. When organic fertilizers are used, (1) Continuously replenish organic fertilizers that are consumed. With chemical fertilizers alone, it will take several years for the soil structure to be destroyed and hardened. (2) Continuously increase soil organic matter content. The content of soil organic matter in most parts of China is relatively low, except for the high content of organic matter in the black soil regions in Northeast China, which can reach 2.5% to 7.5%, and it is less than 1% in most of North China and Northwest China. The content of organic matter in paddy fields in Central and South China is slightly higher. , up to 1.5% to 3.5%. In addition, the drylands rarely reach more than 2%, of which the cultivated land organic content is less than 0.5%, and also accounts for 10.6% of the existing cultivated land area in China. (3) Continuously update soil organic matter. The conversion of organic fertilizers into soil organic matter accounts for about two-thirds of the annual amount of soil organic matter. It can be seen that organic fertilizers must be added in order to continuously update soil organic matter. Obviously, it is very important to apply organic fertilizers to improve soil fertility. 3. Improve soil physicochemical properties After organic fertilizers enter the soil, the organic humus is decomposed and condensed to form a new humus, which can combine with clay and calcium ions in the soil to form an organic-inorganic complex and promote the water-stable aggregate structure in the soil. Formation, which can coordinate the water, fertilizer, gas and heat in the soil. Reduce soil bulk density, improve the soil's cohesiveness and stickiness, and make cultivating better. Due to the porous and porous humus, the adhesion and adhesion force of the humus are smaller than that of the clay and larger than that of the sand. Therefore, the porosity and the air permeability of the viscous soil can be improved, and the loose state of the sand can be changed. The darker color of humus can increase the ability of soil to absorb heat and improve soil thermal conditions. The porous and porous humus has strong water absorption and water retention and can improve the water holding capacity of the soil. Hydroxyl, phenolic hydroxyl or alcoholic hydroxyl groups of humic molecules can dissociate H+ ions in water. The humus is negatively charged, so it can adsorb a large amount of cations and exchange them with the cations in the soil solution, thereby improving the soil's ability to retain fertilizer. From the above, it can be seen that the application of organic fertilizer can effectively fertilize the soil, which is conducive to high yield and stable yield. 4, improve product quality Single application of fertilizer or improper nutrition ratio, will reduce product quality. Practice has shown that the combined application of organic fertilizers and chemical fertilizers can improve product quality, such as increasing protein content in wheat and corn kernels. With the application of fertilizer than the single application of fertilizer quality have improved, wheat protein content increased by 1%, gluten increased by 2.3%, total nitrogen increased by 0.19%. Research from the Soil and Fertilizer Institute of the Chinese Academy of Agricultural Sciences showed that nitrate content in vegetables increased significantly due to unreasonable and excessive topdressing of nitrogen fertilizers, especially for edible parts of Chinese cabbage, spinach, and lettuce, with nitrate up to 1000 μg/g. Up to 1700μg/g, while the manure area is only 200 ~ 500μg/g, the lowest is only a few tens of μg/g. For tomatoes and cauliflower, the use of organic and inorganic fertilizers can increase the vitamin C content by 16.6 to 20.0 μg/g. 5, reduce environmental pollution Organic waste contains a large number of pathogenic eggs, if not treated in time will spread bacteria, so that the groundwater in ammonia, nitrate and soluble organic nitrogen concentration increased, and eutrophication of surface and groundwater, resulting in environmental quality Worsening, even endangering the survival of living things. Therefore, the rational use of these organic fertilizers will not only reduce environmental pollution, but also reduce the use of chemical fertilizers. Organic fertilizers can also adsorb and combine toxic metal cations such as copper and lead to increase arsenic fixation.