What is the function of earthworms?

Earthworms are an important indicator to measure soil health.

Earthworm manure is rich in inorganic salts such as nitrogen, phosphorus and potassium, which can increase soil organic matter, improve soil structure, neutralize acidic or alkaline soil, increase effective components such as phosphorus, and make soil suitable for crop growth. If earthworms disappear from farmland, the soil health index will be poor. Because earthworms can not only loosen soil, increase soil fertility, but also improve soil structure.

Earthworms are translators of soil fertility and creatures symbolizing soil quality. There are no earthworms in the farmland, which means there is something wrong with the soil! So have you noticed that there have been no earthworms in the soil for a long time?

Earthworms breathe with wet body walls. After the heavy rain, they were submerged. Rain pushes out the oxygen in the gaps in the soil, and the oxygen in the soil decreases. Earthworms can't breathe in the soil, so they drill out of the ground to breathe. The activity of earthworms in the soil can loosen the soil and increase the oxygen in the soil, which is beneficial to the respiration and growth of roots.

Why can't earthworms be seen in the cultivated land now?

Since 1950s, the fertilization of crops mainly depends on chemical fertilizers. Due to our long-term emphasis on increasing crop yield per unit area and the extensive use of chemical fertilizers, pesticides and insecticides, the physical and chemical properties of soil have deteriorated, soil fertility has decreased, topsoil loss has accelerated, soil has hardened and chemical properties have deteriorated (soil acidification, soil salinization, soil fertility loss, etc.). ), so that the living environment of earthworms in the soil is destroyed, leading to the reduction or extinction of earthworms. The reduction of earthworms can represent the destruction of soil ecology and the reduction of soil quality!

Soil can't live without it.

Earthworms play the following roles in the ecosystem: consumers, decomposers and regulators.

Earthworms can decompose, decompose and mix organic matter. The feeding activities of earthworms strengthen the biological process of plant residue decomposition, and earthworm manure rich in hydrolyzed nitrogen accelerates the mineralization of surrounding litter.

Earthworm activity can change the spatial distribution of soil organic matter, make soil organic matter distribute in patches, and mix organic matter with mineral soil to form soil particles rich in organic matter.

Earthworms can improve the levels of available nitrogen and phosphorus in soil. Earthworm activity can increase the concentration of mineralized nitrogen in soil, because earthworms consume a large number of soil microorganisms and accelerate the mineralization and turnover of microbial tissues.

The burrowing behavior and feeding habits of earthworms are closely related to the characteristics of soil organic phosphorus sources. The activity of earthworms promoted the downward movement of phosphorus, improved the distribution of phosphorus patches in soil, and significantly changed the status of phosphorus in "hot spots" such as earthworm dung or caves, such as solubility, organic phosphorus pool and alkaline phosphatase activity.

Effect on soil physical and chemical properties

Earthworms have a very important influence on soil structure, aggregate formation and physical conditions required for plant growth and nutrient absorption. Earthworms mainly affect the soil structure through their excreta and pore channels, which can promote the process of soil reunion and make air and water easily reach the roots of plants.

Earthworm activity can also affect soil pH value, redox state, soil temperature and other soil regulating factors. For example, the pH value of earthworm manure is obviously higher than that of the surrounding soil, which can play a certain regulatory role.

Effects on plants, microorganisms and other animals

Effects on plants: Earthworms have an important influence on available nitrogen and phosphorus in the soil, which can promote the growth of plants, and may also change the chemicals in plants, thus affecting the interaction between plants and other organisms. It has obvious influence on the diffusion and burial of plant seeds and the recovery and spatial distribution of plant seedlings.

Effect on microorganisms: In the soil with earthworm, the total amount of microorganisms decreased, while the available nutrients increased. Moreover, after passing through earthworm intestine, although the total amount of microorganisms decreased, the biomass of active microorganisms increased.

Effects on other soil organisms: Earthworms' activities are often beneficial to the survival of other soil animals, for example, it can affect the abundance and diversity of collembola in many ways. Earthworms can directly eat nematodes in soil and litter, or indirectly change the community structure of nematodes through earthworm feces. There are almost no plant parasitic nematodes in earthworm feces, but the proportion of bacterial nematodes has increased obviously.

In addition, earthworm dung also contains 1.4%, 1%, 1%, humic acid 46%, 23 kinds of amino acids, and abundant earthworm protease. There are 105×8 beneficial microorganisms per gram of earthworm manure (only 105-6550 in mature soil), and the 20 cm thick earthworm manure with 85% water content can still reach 45% after 15 days of exposure in hot summer, which greatly enhances the drought resistance of soil. Earthworm enzyme in earthworm manure can also kill viruses, harmful bacteria and substances that inhibit plant growth in soil. Earthworm manure is an ideal natural biological fertilizer. In addition, earthworms can degrade and disperse pollutants in soil.