What is the use of soil organic matter?I don't know!

Organic matter in soil is all organic matter that contains carbon in the soil, including various animal and plant residues, microorganisms, and various organic matters of decomposition and synthesis.Soil organic matter is an important component of soil solid phase section, although a few of the total soil organic matter content of soil, but in soil fertility and plant nutrition has many important functions, mainly includes the following aspects:

01 provide all the nutrients needed for the crop.

Soil organic matter is not only a stable and long-acting nitrogen source material, but it contains almost all kinds of nutrients needed by crops and microorganisms.Soil organic matter releases a large amount of nutrients to plant growth through mineralization.

Mineral process of organic matter decomposition of CO2 is one of the important sources of plant carbon nutrition, it is estimated that the decomposition of soil organic matter and microbial and root respiration of CO2, is up to 13.5 billion tons per year, roughly equivalent to a requirement of land plants.Therefore, the carbon dioxide produced by the mineralization process of soil organic matter is not only an important source of CO2 in the atmosphere, but also an important carbon source for plant photosynthesis and action.

Soil organic matter is the most important nutrient library of soil N and P, which is the main source of plant rapidness N and P.According to the study, 50% to 70% of the nitrogen absorbed by plants comes from soil.92-98% of the soil's total N is stored in organic N in the soil.The content of organic P in soil organic matter generally accounts for 20% to 50% of the total phosphorus in soil. As the decomposition of organic matter, phosphorus is released to provide plant nutrition.

Promote the absorption of other nutrients by plants.

Decomposition of soil organic matter in the transformation process, organic acid and humic acid on soil mineral part have certain ability to dissolve, can promote mineral weathering, is advantageous to the effects of certain nutrients.Some metal ions, which are complex with organic acids and fulvic acids, can be retained in the soil solution without affecting their effectiveness.Some compounds of soil humus and iron are effective for plants and microorganisms in acidic or alkaline soils.

Soil humus is a kind of colloid, has a large specific surface and surface energy, humus give priority to with negatively charged colloid, adsorption in the soil solution to exchangeable cations such as K +, NH4 +, Ca2 +, magnesium 2 +, etc., on the one hand, can avoid the water erosion, on the other hand, can be traded off for plant uptake and its protecting fertilizer performance is very significant.

Soil organic matter also deeply affects the storage of water.According to the determination, the water absorption rate of humus is about 500%, and the water absorption rate of clay minerals is only about 50%.The study showed that soil organic matter increased from 1% to 3%, and the water retention capacity of soil increased sixfold.

Improve the physical properties of soil.

The humus in the soil is rarely in the presence of vagabonds, and most of them are combined with the mineral soil particles, which are coated in the surface of the mineral soil to form an organic-inorganic complex.Due to its soft and flocculent, porous, cohesive force and 11 times stronger than clay, adhesion is half less than clay, clay so be it, after the package is easy to form the scattered broken crumb, make the soil become more soft and no longer form a lump.

Therefore, the organic matter can tighten the sand, loosen the clay, and change the water retention, permeability and ventilation of the soil.In arid areas, organic matter reduces the swelling of the soil by improving the viscosity, and prevents the large fissures (that is, cracks) that occur when the soil is dry.

Humus for brown brown or black material, surrounded by soil particles after dark soil, thereby increasing the soil heat absorption ability, improve the soil temperature, this feature of the northern spring promote seed germination is particularly important.

Promote the reproduction and activity of soil microorganisms.

In the ideal soil ecological system, every square metre of soil containing 1 only vertebrates, snails and slugs, 100, 3000 pot of worm and worm, worm, 5 million, 10 billion protozoa, bacteria and actinomyces, 10 trillion.These animals and microbes make up a food web pyramid, which has a biomass of 400 to 470 kg/mu a year.

Earthworms and other soil animals use organic matter as food and energy sources.Organic matter can improve soil physical environment, increase the degree of osteoporosis and improve permeability, which provides good conditions for soil animal activities, and accelerated the decomposition of organic matter and soil animal itself, further improve the soil permeability, soil microorganisms and plant growth to create a good environmental conditions.

Earthworm manure is a very good granular structure, which has the characteristics of soaking water.The population size of earthworm is an important indicator of healthy soil.

Promote the physiological activity of plants.

Soil organic matter, especially humic acid, has aromatic polyphenol functional group, which can enhance the respiration process of plants, improve the permeability of cell membrane, and promote the rapid entry of nutrients into the plant body.The sodium salt of humic acid can promote the root growth of plants, and sodium humate has a great effect on the root growth and development of grasses and grasses.

Humic acid can promote the physiological activity of plants under certain concentration.The dilute solution of humic acid can change the carbohydrate metabolism in plant, promote the accumulation of reducing sugar, increase the cell's osmotic pressure, and thus enhance the drought resistance of crops.

Soil organic matter also contains vitamin B1, B2, pyrazole alkyd and nicotinic acid, hormones and different auxin (beta indole acetic acid), antibiotics (such as streptomycin, penicillin) on plant growth promoting role, and the ability of plant resistance to.

Reduce pollution of pesticides and heavy metals.

Humus helps to eliminate the toxicity of pesticide residues and heavy metals in soil and the toxicity of Al, Mn and Fe in acidic media.In particular, it can increase the solubility of some pesticide residues in soil, such as DDT and triazobenzene, and accelerate its leaching of soil, reducing pollution and poisoning.

Humic acid can also be complexed with some metal ions, and because of the water solubility of the complex, the toxic metal ions may be discharged into the soil to reduce the harm to crops and soil pollution.