What are the hazards caused by soil erosion?

Soil erosion is very harmful, mainly in the following aspects:

1. Decline or even loss of land productivity: The area of soil erosion in the country has expanded to 1.5 million square kilometers, accounting for about 1.6 percent of the country, and 5 billion tons of soil are lost every year. The loss of nitrogen, phosphorus and potassium fertilizer in the soil is estimated to reach 40 million tons, which is equivalent to the amount of chemical fertilizer used in China in a year, equivalent to an economic loss of 2.4 billion yuan.

The Yangtze River and the Yellow River lose 2.6 billion tonnes of sediment every year. It contains the same amount of organic fertilizer as 50 fertilizer plants with an annual output of 500,000 tons. It is no wonder that some people say that the Yellow River does not carry sediment, but the blood of the Chinese nation, and that such a large area of fertile soil and nitrogen, phosphorus, and potassium fertilizers are washed away, which will inevitably lead to a decline in land productivity or even a complete loss.

2. Silted rivers, lakes and reservoirs: Although the soil erosion in Zhejiang Province is relatively light, the riverbeds of 8 water systems in the province have generally increased by meters, and the length of inland navigation is now 1,000 kilometers less than in the 60s. For example, before 1958, wooden boats with a deadweight of 10 tons could pass from Shengxian County to Cao'e River.

Due to too much silt in the riverbed, it has now been forced to suspend navigation, and the surface water resources have turned into sand, and the aviation construction company has been changed to "Yellow Sand" company.

Dongting Lake in Hunan Province has too much sand due to excessive wind and sand, and more than 1,400 hectares of sandbar are exposed every year. The lake area shrank from 3,915 square kilometers in 1954 to 2,740 square kilometers in 1978. What's more serious is that the water level of Dongting Lake is 3 meters higher than the land around the lake, which loses its role of flood distribution of the Yangtze River.

This is a very serious problem.

Soil erosion is also serious in several river basins in Sichuan Province, including the Jialing River, Fujiang River and Tuojiang River, with more than 20% of the sediment accumulating in reservoirs. According to relevant experts, if this continues, in another 50 years, some reservoirs in the Yangtze River basin will be silted up or turned into sediment reservoirs.

3. Polluted water quality affects ecological balance: At present, a prominent problem in China is the serious pollution of water quality in rivers, rivers and lakes (reservoirs). Soil erosion is an important cause of water pollution. The Yangtze River is being polluted.

It can be seen that soil erosion is not only very harmful, but also has long-term effects. The magnitude of the problem must be fully estimated.

What are the dangers of soil erosion?

1. Wash away the land and destroy the cultivated fields. Especially in the hilly area, the cultivated land is mainly distributed on the ridges above the ditch line, and due to the heavy rainstorm runoff, the area of the gully is getting larger and larger, and the slope surface and cultivated land are getting smaller and smaller.

2. Soil erosion and fertility decline. According to an approximate ratio, the loss of surface soil contains almost 20 kilograms of nitrogen, phosphorus and potassium per tonne. Soil erosion not only reduces the main nutrients of nitrogen, phosphorus and potassium in the soil, but also reduces the content of trace elements such as boron, zinc, copper, manganese and iron in the soil.

It has been determined that the loss of sloping cultivated land is 1 3 1 2 less trace elements than that of the non-lost terraces, which seriously affects the yield and quality of crops.

3. Ecological imbalance, frequent drought and flood disasters. Soil erosion destroys land, vegetation and other ecosystem elements, leading to ecological imbalance, which in turn leads to frequent droughts and floods.

Reducing or even losing land productivity; silted rivers, lakes and reservoirs; polluted water quality affects ecological balance, etc.

The main factors affecting soil erosion are topography, climate, soil quality, and vegetation cover. Human activities affect the degree of soil erosion by affecting topography and vegetation cover.

The terrain slope is steep and the soil erosion is serious; Soil erosion is relatively light in flat areas. Soil erosion is strong in areas with high precipitation intensity, strong soil erosion in loose soil areas, and strong soil erosion in areas with low vegetation coverage. Human activities have destroyed vegetation, destabilized the terrain and exacerbated soil erosion.

Dear Hello I am glad to implicitly answer the following seven kinds of harm caused by soil erosion: 1. Destroying land resources, encroaching on farmland, and endangering the survival of the people with potatoes. 2. Weaken land fertility, cause loss of land nutrients, and exacerbate the occurrence of drought.

3. Sediment silts up the riverbed, aggravating flood disasters. 4. Sediment accumulation reservoirs and lakes reduce the comprehensive application function. 5. The increase of sediment will affect shipping and destroy the traffic safety of the water number.

6. The vicious circle of soil erosion and poverty develops simultaneously. 7. The increase of sediment causes pollution of river water sources.

The factors influencing soil erosion are divided into two categories: natural factors and human factors.

Natural factors are the prerequisites for the occurrence and development of soil erosion, which are mainly manifested in:

1.Precipitation; Generally speaking, the greater the precipitation, the more soil erosion;

2.Terrain; Topography is an important factor affecting soil erosion, and the size of slope, slope length, slope shape, etc. have an impact on soil erosion, and the steeper the slope and the greater the surface runoff velocity, the more serious the soil erosion.

3.Soil; Soil is the main object of erosion, so the permeability, erosion resistance and erosion resistance of the soil itself will also have a great impact on soil erosion. In general, the looser the soil, the more susceptible it is to erosion;

4.Vegetation; The larger the vegetation coverage area, the smaller the soil erosion, and vice versa.

Human factors are the main causes of soil erosion, which are mainly manifested in: vegetation destruction (such as indiscriminate reclamation, indiscriminate logging, indiscriminate grazing) and sloping cultivated land reclamation (such as steep slope reclamation, downhill farming, overgrazing), or due to mining and road construction without taking necessary preventive measures, etc., will aggravate soil erosion.

The influencing factors of soil erosion refer to soil erosion, which is basically the same.

The causes of soil erosion are both natural and man-made.

Natural factors. There are four main aspects: topography, rainfall, soil (ground material composition), and vegetation.

Terrain; The steeper the slope of the ground, the faster the flow rate of surface runoff, and the stronger the erosion of the soil. The longer the slope, the more runoff is collected from the surface, and the stronger the erosion force is.

Rainfall. Rainfall that produces soil erosion is generally a heavy rainstorm with high intensity, and the rainfall intensity exceeds the soil infiltration intensity before surface (over-permeability) runoff is generated, resulting in erosion of the ground surface.

Ground material composition.

Vegetation; Forest and grass vegetation that reaches a certain canopy density has the effect of protecting the soil from erosion. The higher the canopy density, the stronger the retention of water and soil.

The human factor is suspected. The irrational use of land by human beings has destroyed the ground vegetation and stable topography, resulting in serious soil erosion.

Destruction of vegetation.

Unreasonable farming system. Mining.

The hazards of soil erosion are as follows

1. As a result of the decline or even loss of land productivity, China's soil erosion area has expanded to 1.5 million square kilometers, accounting for about 1.6 percent of China's total, and 5 billion tons of soil are lost every year.

2. Silted rivers, lakes and reservoirs, although the soil erosion in Zhejiang Province is relatively light, the riverbeds of 8 water systems in the province have generally increased by meters, and the mileage of inland rivers has decreased by 1,000 kilometers compared with the 60s.

3. Polluted water quality affects the ecological balance, and at present, a prominent problem in China is the serious pollution of the water quality of rivers, rivers and lakes (reservoirs). Soil erosion is an important cause of water pollution.

Soil erosion prevention and control measures

The application of anionic polyacrylamide (PAM) to prevent soil erosion has become a commonly used chemical treatment measure in the world. In 2003, soil and water conservation in the United States reported that Indiana et al. in the United States applied a simulated rainfall device to carry out an experimental study on the application of PAM to prevent and control soil erosion in multi-disturbed farmland, and obtained the experimental results of applying PAM to prevent and control soil erosion in areas with abundant rainfall.

After the first rainstorm event, 20 kg h Pam could reduce the leaching of soil solid particles in agricultural silty loam by 60%, and also slow down the erosion of 60 l min of high-intensity flowing water. Soil treated with PAM in areas prone to severe erosion can effectively control erosion. The study of the simulated rainfall in the initial dry soil showed that 80 kg h pam of the silty loam embankment could reduce the surface runoff and 99% of the soil loss in the silty loam embankment by 86% in 69 mm h rainfall.

In topsoils, air-dried soils sprayed with PAM liquid mist are more effective in controlling erosion in a timely manner than soils treated directly with dry PAM particles. It is believed that this study will have a certain reference role in the experimental research on the application of PAM in the prevention and control of soil erosion in China.