The principle of soil compaction is mainly the phenomenon of structural damage and soil material dispersion on the surface of the soil under external factors, and the cohesive force after drying, which is a common problem encountered in agricultural production. The granular structure of soil is an important indicator of soil fertility. The destruction of soil granular structure leads to a decrease in soil water retention, fertilizer retention, and permeability, resulting in soil compaction; The content of organic matter is an important indicator of soil fertility and particle structure, and the decrease in organic matter leads to soil compaction.
Cause of hardening
Long term single application of chemical fertilizers can not timely supplement Humus, which will not only cause soil hardening, but also may crack. The reason why fertilizer causes soil hardening is that only cations or anions in fertilizer are needed by plants, and plants unilaterally absorb useful ions, causing Soil acidification acidification or salinization.
1. The soil texture of farmland is too sticky, and the cultivation layer is shallow.
The clay has a high content of clay particles, and the average tillage layer is less than 500px. The soil has fewer capillary pores, which have poor ventilation, permeability, and warming properties. After rain or irrigation, it is easy to block the pores and cause soil surface crusting.
2. There is a serious shortage of Manure, and the amount of straw returned to the field is reduced.
The organic matter in the soil is insufficient, the content of Soil organic matter is low, and the structure becomes worse, which affects the activity of microorganisms, thus affecting the formation of soil aggregate structure, resulting in too large or too small soil acidity, leading to soil hardening.
3. Excessive investment in plastic products.
The plastic film and bags are not cleaned thoroughly and cannot be completely decomposed in the soil, forming harmful lumps. Every year in China, plastic waste enters landfills with household waste, accounting for 3% -5% of the weight of landfill waste. Most of it is plastic bag waste, which is difficult to degrade when applied to the soil and causes soil compaction.
4. Long term single fertilization.
There is a serious shortage of Manure. Diazo phosphorus potassium fertilizer reduces Soil organic matter, and Humus cannot be supplemented in time, causing soil hardening and cracking. According to statistics, there was no fertilizer in 1951. Taking corn as an example, the application of farmhouse fertilizer per mu was over 2000kg, resulting in a yield of 96.5kg per mu. In the 1970s, the application of fertilizer per mu was 48.1kg, resulting in an average yield of 239.3kg per mu, an increase of 142.8kg compared to 1951, and an average yield of 2.97kg per kilogram of fertilizer. Since 2000, the application of fertilizer per mu has increased to over 80kg, resulting in a yield of 390kg per mu, an increase of 293.5kg compared to 1951, and an average yield of 3.67kg per kilogram of fertilizer. The yield has not significantly increased, and the input-output ratio is low.
Excessive application of nitrogen fertilizer: when the nitrogen supply of microorganisms increases by 1, the corresponding carbon consumption increases by 25. The carbon consumed comes from Soil organic matter. The low content of organic matter affects the activity of microorganisms, thus affecting the formation of soil aggregate structure and causing soil hardening.
Excessive application of phosphate fertilizer: The phosphate ions in phosphate fertilizer combine with cations such as calcium and magnesium in the soil to form insoluble phosphate, which not only wastes phosphate fertilizer but also damages the soil particle structure, causing soil compaction.
Excessive application of potassium fertilizer: potassium dissociation in potassium fertilizer
Compound Fertilizer, Monoammonium Phosphate, Nitrogen Fertilizer, Phosphate Fertilizer, Potassium Chloride, Potassium Fertilizer, Potassium Sulfate
