Soil conditioners play an important role in improving degraded soils
Soil acidification has become an important factor affecting agricultural production and the ecological environment. Soil acidification begins with active protons (H+). Because of the instability of hydrogen clay, once the hydrogen ions adsorbed on the surface of soil organic-mineral complexes or aluminosilicate clay minerals reach a certain limit, the crystal lattice structure of these particles is destroyed, the aluminum-oxygen octahedron disintegrates, and aluminum ions break free from the constraints of the octahedral lattice and become exchangeable aluminum ions. The hydrolysis of exchangeable aluminum in soil gives the soil its acidic characteristics; depending on the degree of hydrolysis, the hydrolysis of one Al3+ can produce 1 to 3 hydrogen ions. The weathering of primary and secondary aluminum-bearing minerals in acidic soils also accelerates the release of large amounts of aluminum ions, forming aluminum compounds in forms that plants can absorb. When plants absorb excessive aluminum, it not only reduces crop product quality but also greatly affects plant growth, especially root growth, and can even lead to plant poisoning and death. At the same time, acidic soils reduce the cation exchange capacity and base saturation, and calcium, magnesium and sulfur nutrients in soil minerals are lost severely; acidification can also enhance the fixation of phosphate and molybdate in soil, reducing the availability of soil phosphorus and molybdenum and affecting normal plant growth and development.
Soil salinization (alkalization) refers to the process in which salts from the lower soil layers or groundwater rise to the surface with capillary water and, after the water evaporates, accumulate in the surface soil. Soil salinization not only destroys soil structure but also adversely affects crop growth and soil microbial activity. Because salts accumulate in the surface soil, the osmotic pressure of the soil solution increases and the osmotic pressure difference with crop roots decreases, thereby affecting the normal uptake of water and nutrients by crops.
Soil drought has become a widespread condition in certain regions or certain crop-growing areas. China's arid regions account for 30.8% of the national land area and are concentrated in the northwest, with ** having the largest area; **'s total agricultural water use is 77.8 billion m3, accounting for 90% of total water use. Drought can also further worsen the ecological environment and easily trigger other natural disasters.
Soil biological obstacles refer to the phenomenon in natural or farmland ecosystems in which plant-soil interactions cause changes in soil biological populations that are unfavorable to the growth and development of a certain plant. Continuous cropping obstacles are one of the main manifestations of soil biological obstacles. Continuous cropping increases harmful microorganisms in the soil and makes soil-borne diseases and pests severe, causing changes in soil microbial populations and quantities. In addition, soil biological obstacle factors also interact to a certain extent with soil physical and chemical properties. Continuous cropping obstacles can reduce the yield and quality of crops such as peanut, tobacco and vegetables and lower economic returns.
The application of soil conditioners is one of the main measures for remediating degraded soils
1. Improve soil texture and restore vitality to acidified, salinized, compacted and over-fertilized soils.
2. Improve soil continuous cropping obstacles, provide a suitable soil environment for growth, and facilitate a virtuous cycle in the soil.
3. Increase crop yield, improve quality, reduce flower and fruit drop, increase fruit-setting rate, advance harvest and extend the picking period, increase the nutritional level of the fruit, and give good marketability.
4. Prevent pests, diseases and pathogens from harming plants and enhance disease resistance, antibacterial ability and stress resistance.
5. Decompose fertilizer and pesticide residues in soil and in the plant body, and passivate heavy metals to reduce environmental pollution.
6. Improve soil water retention and improve soil adsorption performance.