Saline soils contain mainly salt, why are they called alkaline soils.

Because most of the formation of alkaline and alkalized soil in China is related to the accumulation of carbonates in the soil, so it is called saline soil.

The main factors affecting the formation of saline and alkaline soil are as follows:

1. Climatic conditions

The arid and semi-arid areas of Northeast, Northwest, and North China have low precipitation and high evaporation, and the salt dissolved in water is easy to be accumulated on the soil surface. Summer rainfall, concentrated, a large number of soluble salt seepage into the lower layers or with the loss of water, for the "desalination" season.

Spring surface water evaporation is strong, the salt in the groundwater with the rise of capillary water and gathered in the soil surface, which is the main "salt return" season. Northeast, North China and semi-arid areas of saline soils have obvious "fade" and "salt return" season, while the northwest due to low precipitation, the seasonal changes in soil salinity is not obvious.

2, geographical conditions

Topographic location has a great influence on the formation of saline soil. Topographic location directly affects the movement of surface water and groundwater, which is closely related to the movement and accumulation of salt. In terms of the general topography, water-soluble salt goes from high to low and accumulates in low-lying areas.

Saline soils are mainly distributed in inland basins such as the Songliao Plain, mountain depressions, plains and other poorly drained areas. From the small terrain (localized extent), the accumulation of salt in the soil is opposite to the large terrain. Salt often accumulates in small raised areas.

3. Soil texture and groundwater

The coarse texture structure affects the rate and height of soil capillary water movement. In general, capillary water rises faster and faster in loamy soils, and salt accumulates slower and slower in sands and clays. Groundwater The key issues affecting soil salinity are the water table and groundwater salinity. A high water table is highly saline and prone to salt accumulation.

4. Influence of rivers and seawater

The land on the banks of rivers and canals increases the water table due to seepage from rivers, which promotes the accumulation of salt. Seawater immersion in coastal areas can form coastal saline soils.

5, improper farming management

In some places, when flooding or low-lying areas, only irrigation without drainage, so that the water table rises rapidly, salt accumulation, so that the original good saline and alkaline land, this process is called secondary salinization. In order to prevent secondary salinization, should be supported by drainage and irrigation facilities, strictly prohibit diffuse irrigation, irrigation should be promptly tilled and hoeing after the end of the irrigation.

Expanded Information:

Saline land improvement measures:

1, water conservation improvement

Establishment of a perfect drainage and irrigation system, separate drainage and irrigation, strengthen the management of water, strict control of the water table, through irrigation irrigation, flood diversion, siltation, and constantly drenching and removing the salts in the soil.

2, agricultural technology improvement

Through deep plowing, leveling the land, filling guest soil, mulching, turning silt, mulching sand, increasing the application of organic fertilizers and other measures to improve the composition and structure of the soil, improve the permeability of the soil, accelerate the salt leaching.

3, biological improvement

Planting and tilling green manure pasture, straw return, application of fungal fertilizer, planting salt-tolerant plants, afforestation, etc., to improve soil fertility, improve soil structure, and improve the microclimate of the farmland, reduce the evaporation of surface moisture, inhibit the return of salt.

4, chemical improvement

To alkaline soil, alkalized soil, soda salt soil apply gypsum, black alum and other improvers, reduce or eliminate soil alkali, improve soil physical and chemical properties. Various measures should pay attention to both the integrated use, but also to the local conditions, in order to achieve the desired results.

Baidu Encyclopedia-Saline Soil

Baidu Encyclopedia-Saline Soil Improvement