2022/3/29 17:20:24 阅读：205 发布者：chichi77
Over the past decade, soil degradation has been considered to be the main cause of low productivity and crop failure.
“Today soil degradation affects approximately 15% of Earth's ice-free land surface, and irreversible erosion has occurred in an area of approximately 430 million ha. In Asia, approximately 40% of the soils are classified as degraded.”
What is Soil Degrataion?
Soil degradation refers to the phenomenon that under the influence of various natural factors, especially human factors, different intensities of erosion can lead to the decline of soil quality and productivity of agriculture, forestry and animal husbandry, and even the overall deterioration of soil environment. Under the influence of erosion, soil degradation can be divided into physical, chemical, and biological degradation.
Physical Degradation
Soil physical degradation mainly includes soil thinning, soil desertification or gravitation, soil compaction, and soil available water decline.
Chemical Degradation
Soil chemical degradation includes the decrease of soil available nutrient content, nutrient imbalance, high soluble salt content, soil acidification, and alkalization, etc.
Biological degradation
Soil biological degradation mainly refers to the reduction of soil microbial diversity, the change of community structure, the increase of harmful organisms, the disorder of biological processes, and so on.
What Factors Have Caused Soil Degradation?
Physical factors
The different kinds of wind and water erosion may cause the loss of topsoil. Therefore, causes Soil Degradation, since the quality of soil mostly relies on the topsoil.
Chemical factors
“ It is caused by salt buildup and leaching of nutrients which corrupt the quality of soil by creating undesirable changes in the essential soil chemical ingredients. “The chemical factors of Soil Degradation are mainly due to the releasing of toxic substances and depletion of nutrients, such as waterlogging, acidity, or alkalinity. (salinization)
Biological factors
Biological factors are mostly caused by human interactions and the over-usage of soil. For example, people’s poor practices of farming would destroy the ecological balance in the soil. Which further on, causes the depletion of microbial activities that diminishes the soil’s fertility.
Other factors
Deforestation, improper usage of pesticides, Industrials and mining activities, and numerous factors can all contribute to the quickening of soil degradation. Natural Factors, such as extreme weather, which we would not be able to prevent, may also lead to soil degradation.
Why Should We Pay Attention and What Can We Do?
At present, soil and land degradation caused by various unreasonable human activities has seriously threatened the sustainability of world agricultural development.
According to statistics, the global area of soil degradation has reached 19.65 million square kilometers. In terms of regional distribution, soil degradation is particularly prominent in Asia and Africa, which are located in the tropical and subtropical regions. Of the seriously degraded soil of about 3 million square kilometers, 1.2 million square kilometers are distributed in Africa and 1.1 million square kilometers are distributed in Asia; In terms of soil degradation types, soil erosion degradation accounts for 84% of the total degradation area, which is one of the main causes of soil degradation; In terms of degradation level, soil degradation is mainly moderate, serious and extremely serious, and mild degradation accounts for only 38% of the total degradation area.
The results of the global assessment of soil degradation show that soil erosion is the most important form of soil degradation, with water erosion accounting for 56% and wind erosion accounting for 28% of the global degraded soil; As for the motivation of water erosion, 43% is due to forest destruction, 29% is due to overgrazing, 24% is due to unreasonable agricultural management, while the motivation of wind erosion, 60% is due to overgrazing, 16% is due to unreasonable agricultural management, 16% is due to overdevelopment of natural vegetation and 8% is due to forest destruction; The global total area affected by soil chemical degradation (including soil nutrient attenuation, salinization, acidification, pollution, etc.) is 2.4 million km2, which is mainly due to the unreasonable utilization of agriculture (56%) and the destruction of forests (28%); The total area of physically degraded soil in the world is about 830000 square km, which is mainly concentrated in temperate regions, and most of it may be related to the compaction of agricultural machinery.
Although soil is a renewable natural resource and can recover or repair pollution, overutilization or pollution not only makes it very difficult to recover and control but also takes a long time. Therefore, the prevention and control of soil pollution and soil degradation must be based on prevention, supplemented by treatment and comprehensive treatment. The prevention and control of soil degradation is a systematic project. In addition to scientific fertilization and irrigation and rational cultivation, especially the popularization and application of grain and grass rotation, flood and drought rotation, and conservation tillage, the focus is on the prevention and control of soil water erosion and soil wind erosion.
Written by: Isabella 8(5)
来源：ECO CAP Shanghai
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