What are the functions and benefits of organic fertilizers?
What are the functions of organic fertilizers? Please explain. There are mainly five functions of organic fertilizers, listed below for reference: 1. Organic fertilizers can supply crops with nutrients and active substances and increase the intensity of photosynthesis. In the process of continuous mineralization in the soil, organic fertilizers can supply crops with the necessary...
What are the functions of organic fertilizers? Please explain.There are mainly five functions of organic fertilizers, listed below for reference:
1. Organic fertilizers can supply crops with nutrients and active substances and increase the intensity of photosynthesis
In the process of continuous mineralization in the soil, organic fertilizers can supply crops with a variety of essential nutrient elements over a long period, and can also supply a variety of active substances, such as amino acids, ribonucleic acid, humic acid and various enzymes.
Especially in livestock and poultry manure, enzyme activity is particularly high, tens to hundreds of times that of soil enzyme activity. It can not only nourish plants, but also stimulate crop growth, and can also enhance soil microbial activity and improve the availability of soil nutrients.
During the decomposition of organic fertilizers, a large amount of CO2 is produced for crops to carry out carbon assimilation. Within a certain CO2 concentration range, the intensity of plant photosynthesis rises linearly with the increase in CO2. According to tests in Beijing, Fujian and other places, increasing the CO2 concentration can increase crop yields by more than 10%. Organic fertilizers are rich in carbon sources, which is of great significance for promoting crop growth and increasing yields.
2. Organic fertilizers can improve soil fertility
Soil organic matter is one of the main indicators for measuring the level of fertility, the material basis of soil fertility, and the material source for replenishing and renewing soil organic matter.
When organic fertilizers are applied, (1) the consumed organic fertilizers are continuously replenished. Relying solely on chemical fertilizers, within just a few years, the soil structure will be destroyed and become compacted.
(2) The soil organic matter content is continuously increased. In most areas of China, the soil organic matter content is relatively low. Except for the black soil region of the Northeast, where the organic matter content is relatively high, reaching 2.5%-7.5%, most areas such as North China and Northwest China are below 1%, while the organic matter content of paddy fields in Central China and South China is slightly higher, reaching 1.5%-3.5%. In addition, dryland areas can rarely reach more than 2%, among which cultivated land with an organic matter content below 0.5% still accounts for 10.6% of China's existing cultivated land area.
(3) Soil organic matter is continuously renewed. Organic fertilizers converted into soil organic matter account for about two-thirds of the annual formation of soil organic matter, which shows that organic fertilizers must be supplemented to continuously renew soil organic matter. It is very clear that applying organic fertilizers is very important for improving soil fertility.
3. Organic fertilizers can improve the physical and chemical properties of soil
After organic fertilizers enter the soil, they are decomposed by microorganisms and condensed into new humus, which can combine with clay and calcium ions in the soil to form organic-inorganic complexes, promoting the formation of water-stable aggregate structure in the soil, thereby coordinating the contradictions among water, fertilizer, air and heat in the soil.
It reduces soil bulk density, improves the cohesiveness and adhesiveness of the soil, and makes tillage better. Because humus is loose and porous, its adhesiveness and cohesiveness are smaller than those of clay and larger than those of sandy soil, so it can not only improve the looseness and aeration of clayey soil, but also change the loose state of sandy soil.
Humus is darker in color, which can improve the soil's heat absorption capacity and improve the soil's thermal conditions. Humus is loose and porous with strong water absorption and storage capacity, which can improve the soil's water-holding capacity.
The hydroxyl groups of humus molecules, phenolic hydroxyl groups or alcoholic hydroxyl groups can dissociate H+ ions in water. This makes humus carry negative charges, so it can adsorb a large number of cations and exchange with cations in the soil solution, thereby improving the soil's fertilizer-holding capacity. From the above, it can be seen that applying organic fertilizers can effectively build soil fertility and is conducive to high and stable yields.
4. Organic fertilizers can improve product quality
Applying chemical fertilizers alone or with an improper nutrient ratio will reduce product quality. Practice has proved that the combined application of organic fertilizers and chemical fertilizers can improve product quality, such as increasing the protein content in wheat and corn grains. Compared with applying chemical fertilizers alone, the combined application improves quality in all respects: wheat protein content increases by 1%, gluten increases by 2.3%, and total nitrogen in grains increases by 0.19%.
Research by the Institute of Soil and Fertilizer of the Chinese Academy of Agricultural Sciences shows that unreasonable and excessive topdressing of nitrogen fertilizer significantly increases the nitrate content in vegetables. In particular, in the edible parts of Chinese cabbage, spinach and lettuce, nitrate can reach as high as 1000 μg/g, with the highest reaching 1700 μg/g, while in the farmyard manure plot it is only 200-500 μg/g, with the lowest only a few dozen μg/g. For tomatoes and cauliflower, the combined use of organic and inorganic fertilizers can increase the vitamin C content by 16.6-20.0 μg/g.
5. Organic fertilizers can reduce environmental pollution
Organic waste contains a large number of pathogenic bacteria and insect eggs. If not treated in time, it will spread pathogens, increase the concentration of ammoniacal, nitrate and soluble organic nitrogen in groundwater, and cause eutrophication of surface water and groundwater, deteriorating environmental quality and even threatening the survival of organisms.
Therefore, the rational use of these organic fertilizers can not only reduce environmental pollution, but also reduce chemical fertilizer input, achieving two goals at once. Organic fertilizers can also adsorb and chelate toxic metal cations such as copper and lead, and increase the fixation of arsenic.
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