What are the common methods of soil improvement?

Soil improvement is the process of taking corresponding physical, biological or chemical measures to improve soil properties, increase soil fertility, boost crop yields and improve the soil environment for human survival, targeting poor soil texture and structure. Let's take a look at what soil improvement methods there are!

Soil improvement process

1. Soil conservation stage: The soil conservation stage involves taking engineering or biological measures to keep soil loss within the allowable loss range. If soil loss cannot be controlled, soil improvement cannot proceed either. For cultivated soil, farmland capital construction must first be carried out.

2. Soil amelioration stage: The purpose of the soil amelioration stage is to increase soil organic matter and nutrient content, improve soil properties and raise soil fertility. The main amelioration measures are planting leguminous green manure or applying more farmyard manure. When the soil is too sandy or too clayey, the method of blending sand and clay together can be used. In the acidic red-yellow soil areas of southern China, the eroded soil is very deficient in phosphorus, so phosphate fertilizer must be applied when planting green manure crops to improve the soil.

Soil improvement techniques

1. Soil structure improvement: Soil structure improvement is achieved by applying natural soil conditioners (such as humic acids, cellulose types, biogas residue, etc.) and artificial soil conditioners (such as polyvinyl alcohol, polyacrylonitrile, etc.) to promote the formation of soil aggregates, improve soil structure, raise fertility and stabilize topsoil, protect the soil plow layer and prevent soil erosion.

2. Saline-alkali land improvement: Saline-alkali land improvement is mainly carried out through desalination agent technology, well irrigation technology for dry fields in saline-alkali soil areas, and biological improvement technology.

3. Acidified soil improvement: Acidified soil improvement involves controlling the emission of carbon dioxide from waste gas, halting the development of acid rain, or adding soil conditioners such as sodium carbonate and slaked lime to already acidified soil to improve soil fertility and increase soil permeability and aeration.

4. Soil heavy metal pollution improvement: Soil heavy metal pollution improvement mainly involves taking biological measures and amelioration measures to extract heavy metals from the soil, enrich and transport them to the harvestable parts of plants, or adding conditioners to contaminated soil so that heavy metals undergo oxidation, reduction, precipitation, adsorption, inhibition and antagonism.

Soil improvement methods

1. Rotate crops and change stubble in a planned way: Arrange different vegetables reasonably, and consider as much as possible the family and genus types of different vegetables, root depth, fertilizer absorption characteristics and the acidity or alkalinity of their secretions, etc.

2. Regularly disinfect the soil

① Chemical method: Formalin can be mixed into the soil, or sulfur powder can be used for fumigation to sterilize.

② Sunlight method: During the idle stubble period in summer, remove the greenhouse film, deep-plow the soil and use ultraviolet rays in sunlight to sterilize.

③ High-temperature method: In hot seasons, after watering, close up the greenhouse, or hot steam can be passed into the soil to kill insects and sterilize.

④ Freezing method: In severe winter cold, after removing the film from protected land that cannot be used, deep-plow the soil to freeze pests and eggs to death.

3. Improve soil texture

① After harvesting vegetables, plow the soil and turn the lower layer of soil, which contains less salt, up to the surface layer and mix it thoroughly with the topsoil.

② Appropriately increase the application of decomposed organic fertilizer to increase the content of soil organic matter.

③ For soil whose surface layer has too high a salt content or too low a pH value, fertile soil can be used to replace it.

④ Those with the permitted economic and technical conditions can carry out soilless cultivation.

4. Drain salt with water

① During idle stubble, water heavily so that the salt accumulated in the topsoil is leached downward to reduce the concentration of the soil solution.

② During the gap when vegetables are being changed in summer, remove the film to let rain leach the soil or use heavy flooding irrigation. This causes the salt in the surface soil to be lost with rainwater or leached into the deep soil layer.

5. Scientific fertilization

① According to soil nutrient status, fertilizer types and the fertilizer requirements of vegetables, determine a reasonable fertilization amount or fertilization method, achieve formula fertilization, mainly apply organic fertilizer, reasonably combine nitrogen, phosphorus and potassium fertilizers, and when chemical fertilizer is used as base fertilizer, it should be applied deeply and mixed with organic fertilizer. When used as topdressing, it should be “small amounts many times,” and avoid long-term application of the same fertilizer, especially nitrogen-containing fertilizers.

② Choose fertilizers scientifically, and pay attention to alternating and combining physiologically acidic fertilizers with physiologically alkaline fertilizers. When the soil has already become acidified or acidic fertilizer must be applied, quicklime can be mixed into the fertilizer to adjust it. When the soil is severely acidified and the pH value needs to be raised quickly, slaked lime can be applied, but the amount used is 1/3 to 1/2 that of quicklime, and it must not be applied to soil where plants are currently growing.

③ Advocate foliar topdressing, as foliar topdressing will not cause soil damage.

④ Apply micro-fertilizers cautiously. Under normal circumstances, organic fertilizer should be used to provide trace elements. If micro-fertilizers are applied, be sure not to use them in excess.

6. Plant salt-tolerant crops: After harvesting vegetables, plant crops with strong fertilizer absorption such as corn, sorghum and cabbage, which can effectively reduce the salt content and acidity of the soil. If the soil has salt accumulation or strong acidity, salt-tolerant vegetables such as spinach, celery and eggplant can be planted, or crops with relatively strong acid tolerance such as rapeseed, water spinach and taro, to achieve the purpose of absorbing soil salt.