The impact of land salinization on agricultural production in Northwest China

Soil salinization refers to the fact that the soil salt content is too high (exceeding, and the crops are low or cannot grow.

There are two conditions for the formation of saline-alkali soil: first, the climate is arid and the groundwater level is high (above the critical water level); The other is low-lying and there is no way to drain the water. Groundwater contains a certain amount of salt, and if its water surface is close to the ground, and the area is relatively arid, the water that rises to the surface due to capillary action evaporates, leaving salt

Over time, the salt content of the soil gradually increases, forming saline-alkali soil. If it is a depression and there is no drainage outlet, the water in the depression will evaporate, leaving salt and forming a saline-alkali land.

Adverse effects: 1. Soil compaction and fertility decline.

2. It is not conducive to the absorption of nutrients by crops and hinders the growth of crops.

Prevention and control: the measures to control saline-alkali land include water conservancy improvement measures (irrigation, drainage, dredging, rice planting, seepage prevention, etc.); agricultural improvement measures (land leveling, improved tillage, soil application, fertilization, sowing, crop rotation, intercropping, etc.); biological improvement measures (planting salt-tolerant plants and pastures, green manure, afforestation, etc.); and chemical improvement measures (application of improved substances such as gypsum, phosphogypsum, calcium sulfite, etc.). Four aspects.

Since each measure has a certain scope of application and conditions, it is necessary to adapt measures to local conditions and comprehensively deal with them.

d The completion of the Aswan Dam changed the annual frequency of the Nile and reduced the water flow of the lower reaches of the river. It has formed a "pull a hair and move the whole body".

Hello, glad to have a question for you. 1. Strengthen the monitoring of soil salinity, discover the situation of soil salinization in time, and take effective measures to prevent and control it. 2. Strengthen the popularization of science on soil salinization, guide farmers to effectively use soil and improve the level of agricultural production.

3. Strengthen the treatment technology of soil salinization, adopt technologies such as plant resistance to salinity, increase the application of organic fertilizer, and improve soil to effectively prevent and control soil salinization. 4. Strengthen policy support for soil salinization, actively promote soil improvement technology, promote the investment of a large amount of money in soil improvement, and promote the improvement of soil salinization. 5. Strengthen soil and water conservation in Northwest China, establish and improve the soil and water conservation system, strengthen scientific and technological support for soil and water conservation, protect the soil, and prevent soil salinization.

Hope mine is helpful to you.

Most of the northwest regions of China belong to arid and semi-arid areas. The cause of salinization is the lack of precipitation and serious loss of water evaporation, because the water source is precious, the soil is only irrigated and not drained, resulting in the salt of the soil bottom layer or groundwater rising to the surface with the capillary water, after the high temperature makes the soil surface water evaporate, the salt accumulates in the surface soil, and when the soil salt content is too high (exceeded, soil salinization occurs.

The reasons for soil salinization in Northwest China are as follows: (1) The climate in Northwest China is arid, precipitation is scarce, and agricultural production needs irrigation;

2) Over-irrigation when irrigating farmland, only irrigation but not drainage, causing the groundwater level to rise, bringing the salt from the deep layers of the soil to the surface. After the water evaporates, the salt remains in the surface soil, forming land salinization;

3) Poor vegetation and strong winds in winter and spring. High winds blow the salt of the saltwater lake onto the surrounding land, causing the land to salinize;

Saline-alkali land can be divided into light saline-alkali land, moderate saline-alkali land and heavy saline-alkali land according to its utilization. Light saline-alkali land means that its emergence rate is about 780%, and its salt content is less than 3 thousandths; Heavy saline-alkali land means that its salt content is more than 6 parts per thousand, and the emergence rate is less than 50; In the middle is moderately saline-alkali land. Saline-alkali land is mainly composed of NaCl, MgCl2, KCl, CaCl2, MgSO4 and other salts, and the so-called alkali mainly refers to Na2CO3.

The ratio of various components depends on the place, and the degree of salinization varies greatly from place to place. All kinds of saline-alkali soils are formed under certain natural conditions, and the essence of their formation is mainly the redistribution of various soluble salts in the horizontal and vertical directions on the ground, so that the salt gradually accumulates on the soil surface in the salt-collecting area. The main factors affecting the formation of saline-alkali soil are:

1. Climatic conditions - in the arid and semi-arid areas of northeast, northwest and north China, the precipitation is small, the evaporation is large, and the salt dissolved in the water is easy to accumulate on the soil surface. In summer, the rain is abundant and concentrated, and a large amount of soluble salt seeps into the lower layer or flows away with the water, which is the "desalination" season; In spring, the surface water evaporates strongly, and the salt in the groundwater accumulates on the surface of the soil as the capillary water rises, which is the main "salinity" season. The saline-alkali soils in Northeast China, North China and semi-arid regions have obvious "desalination" and "salinization" seasons, while in Northwest China, due to the low amount of early precipitation, the seasonal variation of soil salinity is not obvious.

Soil salinization occurs in BAI

Arid du, semi-arid zone. zhi

The reason is that due to flood irrigation and only irrigation without drainage, the groundwater level rises or the salt content of the bottom layer of the soil or groundwater rises to the surface with the capillary water, and after the water evaporates, the salt accumulates in the surface soil, and when the soil salt content is too high (exceeded, the formation of a salinity-alkali disaster.

China's saline soil or saline-alkali soil has a wide distribution range, large area and many types, with a total area of about 100 million hm2. It occurs mainly in arid, semi-arid and sub-humid regions. The soluble salts of saline-alkali soils mainly include sulfates, chlorides, carbonates and bicarbonates such as sodium, potassium, calcium, magnesium, etc.

Sulfates and chlorides are generally neutral, and carbonates and bicarbonates are alkaline salts.