On "soil sludge" this article is the most comprehensive!
Soil compaction refers to the lack of organic matter due to the lack of organic matter, poor structure, under the influence of irrigation, rainfall and the dispersion of soil material, and after drying, the soil surface becomes hardened by cohesion.
一.How does the soil compaction form?
(1) The content of organic matter is an important indicator of soil fertility and mass structure. The reduction of organic matter leads to soil compaction. The low content of soil organic matter affects the activity of microorganisms, thus causing the formation of soil mass structure, leading to soil compaction.
(2) When excessive potassium fertilizer is applied to the soil, the potassium ion replacement in the potassium fertilizer is particularly strong, which can replace the multivalent cations forming the soil mass structure, while the monovalent potassium ion does not have the role of bond bridge, and the bond bridge of the soil mass structure is destroyed, which destroys the mass structure, resulting in soil compaction.
(3) Soil mass structure is an important indicator of soil fertility. The destruction of soil mass structure leads to the reduction of soil water retention capacity and permeability, resulting in soil compaction.
(4) The soil particle structure is composed of negatively charged soil clay particles and organic matter connected by positively charged multivalent cations.
(5) the acid and alkaline level of the soil is too large or too small, the following acid rain.
二.Factors that cause the soil compaction
1. Farming methods
In the process of agricultural farming, many people choose rotary farming, such farming can achieve surface leveling, soil finely, save the benefits of labor, thus popularize higher, but the depth of rotary tillage is often too shallow, farmland soil texture too sticky, clay clay content, combined with the cultivation layer average less than 20 cm, soil capillary pores in less, ventilation, permeability, heating, after the rain, easy to block pores, soil surface skin.
2. Excessive use of chemical fertilizer
(1) In the use of fertilizer, people often ignore the harm of chemical fertilizer. Too much, the use of chemical fertilizer, straw returning, make the organic material in the soil, soil organic matter content is low, structure, soil nutrient imbalance, especially the use of potash and ammonium nitrogen fertilizer, a soil mass structure damage, affect the activity of microorganisms, cause soil acid alkaline too large or too small, lead to soil compaction.
(2) The application of organic fertilizer is seriously insufficient. Heavy nitrogen, light phosphorus and potassium fertilizer, soil organic matter decline, humus matter can not be replenished in time, causing soil compaction and cracking.① Excessive application of nitrogen fertilizer: the nitrogen supply of microorganisms increases by 1, the corresponding consumption of carbon will increase by 25, the carbon consumption comes from soil organic matter, organic matter content is low, affecting the activity of microorganisms, thus affecting the formation of soil mass structure, leading to soil compaction.② Excessive application of phosphate fertilizer: the phosphate ions in the phosphate fertilizer and calcium, magnesium and other cations in the soil combined to form insoluble phosphate, namely the waste of phosphate fertilizer, and destroyed the soil mass structure, resulting in soil compaction.③ Excessive application of potassium fertilizer: the potassium ion replacement in potassium fertilizer is particularly strong, can replace the multivalent cation of the soil mass structure, and the monovalent potassium ion does not have the role of a bond bridge, the bond bridge of the soil mass structure is destroyed, also destroyed the mass particle structure, resulting in soil compaction.
3, the use of plastic products
In the facility shed, because the mulch and plastic bags are not cleaned up, they can not be completely decomposed in the soil, forming harmful blocks. Every year in China, the waste plastic entering the landfill site accounts for 3% -5% of the weight of the landfill waste. Most of them are plastic bags, which are not easy to degrade into the soil, resulting in soil compaction.
4. Mechanical suppression and ploughing Due to the influence of too deep mechanical tillage, the soil particle structure was destroyed. Every year, only part of the fertilizer applied into the soil is absorbed and utilized by the seasonal crops, and the rest is fixed by the soil, forming a large amount of acid deposits, resulting in soil compaction.
5. Unreasonable irrigation Due to the unreasonable drought resistance, the use of flood irrigation, coupled with dry climate and other factors, most of the water is evaporated in a short time, resulting in soil surface compaction, may also cause the phenomenon of flooding, resulting in serious damage to the soil mass structure, the formation of soil compaction.
6, the accumulation of soil harmful substances In some places, the content of groundwater, industrial wastewater and toxic substances is high, and the excessive accumulation of toxic substances in the long-term use of irrigation causes the surface soil compaction.
7. Heavy rain soil erosion
After the rainstorm, the fine soil particles of the topsoil layer were taken away, destroying the soil structure.
三.The harm of soil hardening
1, the plant root respiration is blocked In the case of soil compaction or long-term flooding, cell respiration in the root of plants is weakened, and nutrients such as nitrogen mostly exist in ionic state, absorbed by active transport, to consume the energy produced by cell metabolism. Breaath is weakened, so the energy supply is insufficient, affecting absorption.
2, the plant roots can not develop normally Soil mass structure is an important indicator of soil fertility. The destruction of soil mass structure leads to the reduction of soil water retention capacity and permeability, resulting in soil compaction. The roots of plants in this state will decrease their vitality due to hypoxia.03
3, resulting in plant deficiency disease The symptoms of plant deficiency are not necessarily the lack of this element in the soil, but the decrease of root absorption capacity caused by a series of problems such as soil compaction, unsuitable soil pH, or uneven soil water supply.
四.The solution path of soil hardening
1. Deep ploughing and rotary tillage combination Scientific and moderate deep tillage should be about 35 cm, which is conducive to the protection of soil tillage layer structure and the growth of crop roots.
2. Improve the sticky soil The characteristics of soil physical and chemical properties were completely changed by using sand soil and organic fertilizer.
3. Effectively promote straw returning to the field Straw returning to the field can improve the physical properties of soil, straw crushing returning to the field can improve the soil organic matter content, increase soil porosity, coordinate water, fertilizer and gas heat in soil, create a good environment for soil microbial activities, which is conducive to organic matter decomposition, softening and improvement of soil physical and chemical properties.
4. Appropriate use of soil amendments Using the soil improvement conditioner, the divalent cations such as silicon, calcium and iron in the conditioner and the organic and inorganic colloid in the soil can quickly form the soil particle structure, solve the problem of soil compaction, promote the growth of crop roots, and adjust the proportion of solid phase, liquid phase and gas phase of the soil.
5. Adopt soil testing and formula fertilization technology According to the soil test basis, using the combination of organic and inorganic fertilizer, organic fertilizer, reduce pure chemical fertilizer, reasonable application of organic activation of fertilizer nutrition package jia beauty dividends, profit, potassium, etc., the soil not only not harden soil, and will increase the organic matter content, improve the soil structure, at the same time of increasing fertility increase water permeability, further improve the quality of soil, can avoid the occurrence of hardening.
6. Promote sloping land cultivation technology
Using soil gathering and cultivation technology to reduce soil erosion during rainstorm.
7, saline land and non-saline land
(1) Non-saline land
The main reason for soil compaction is the destruction of soil structure, and the soil bulk density can be reduced by deep ploughing, deep turning, planting green fertilizer and returning to the field, and applying more organic fertilizer.
(2) Salt alkali land
It can be done by flood irrigation and pressure salt, digging alkali drainage channel (both methods are water to wash away salt) combined with some agronomic measures such as planting green fertilizer (saline-alkali plants), applying organic fertilizer, leveling the land and other methods.
8, the rational use of fertilizer
(1) The use of beneficial bacteria
Organic matter breaks down in soil to form humus in soil, and finally promotes the formation of mass structure from soil microorganisms. Therefore, to break the soil compaction to timely application of fertilizer containing bacteria, increase the soil microorganisms.
(2) Use of humic acid fertilizers
Humus is the main component of the mass structure, and humus is mainly obtained by the decomposition of organic matter by soil microorganisms. Therefore, directly supplementing sufficient humic acid to the soil can greatly increase the number of aggregate structures, thus improving the soil compaction problem.
(3) Increase the use of soil conditioner, and the specific effects of soil conditioner are as follows:
Increase the use of soil conditioner, and the specific effects of soil conditioner are as follows:
Improve the soil permeability. Due to improper fertilization and other problems, the soil compaction situation is also quite serious. The addition of some soil conditioner can promote the formation of the aggregate structure, thus breaking the hardening and increasing its air permeability.
Supplement of soil nutrition. Some soil regulators are rich in trace elements such as silicon, calcium, magnesium, which can promote root growth. The application of such soil regulators can replenish soil nutrients to some extent...
Inhibit harmful bacteria. Some soil conditioner have a certain bactericidal effect, after application, can reduce the occurrence of soil-borne diseases.
Improve the utilization rate of fertilizer, promote crop high yield and high quality.