How to solve soil salting

Farmers in old vegetable areas have such a saying: One year is good, two years are flat, and three years are poor. The reasons for this are of course many. From the aspect of the soil or the factors closely related to the soil, there are mainly serious soil salinization, soil acidification and continuous cropping obstacles.
Soil salinization occurs mainly in two aspects: First, the greenhouse temperature is high, the soil evaporation is large, and the salt rises with the evaporation of water to the soil surface; at the same time, due to the long-term cover of the film in the greenhouse, the amount of water Less, and the soil is not directly showered by rain, so these salt levels that rise up to the surface of the soil can hardly be lost. Second, the growth rate of vegetable crops in greenhouses is fast. In order to meet the nutritional needs of vegetable growth and development, a large amount of fertilization is required. However, due to soil types, soil texture, soil fertility, and the diversity of nutrient absorption in the growth and development of vegetable crops. In terms of complexity, it is difficult for peasants to grasp their suitable types and amounts of fertilizers. Therefore, excessive fertilization often occurs. Therefore, fertilizers that have not been absorbed and utilized remain in the soil and accumulate in large amounts over time, resulting in soil salinity. Staining.
In open field conditions, the amount of fertilization in the field is often much larger than the actual amount of actual crop production, and part of it is used for the loss caused by precipitation. The amount of fertilization in the greenhouse is far more than exposed, of course, greatly exceeds the actual amount of production. During the production of plastic sheds, there is generally no leaching loss of precipitation, so a large surplus of fertilizer remains in the soil. Inorganic fertilizers accumulate in the soil for many years and a large amount of salt is left in the soil, which increases the concentration of the soil solution and causes damage to the cultivated crops.
So how to solve the problem of soil salting? First of all, we must learn to distinguish the degree of soil salinity, which is mainly observed from the soil surface conditions and vegetable growth performance in two aspects.
When looking at the surface of the soil, there are several factors to consider: First, the soil that has not been salted sees water seepage faster, and after the occurrence of salting, water infiltration is difficult. Second, if the soil is dry, the surface will turn white. Thirdly, the vacated land is slightly left on the ground and white crystals will appear on the ground. This indicates that the degree of salting is already quite high, at least indicating that the soil solution during the cultivation of the former plant had a high concentration of 5000 mg/kg or more. The fourth is the occurrence of Penicillium on the surface of the soil, indicating that the salt concentration is already high here. In particular, when the red mold occurs, the salt concentration is already quite high.
Observing the growth performance of vegetables, we need to consider: First, the lack of vitality of the leaves, when severe noon appears to be sluggish, and recover at night, which is the result of root water absorption, but should be differentiated from some root and neck diseases. The second is that the color of the leaves becomes extremely thick and sparkling. Third, poor fruit enlargement, fruit peels such as tomatoes are bright, coloring is poor, and red and green boundaries are clearly defined. The fourth is that the root is brown and the apex is blunt. Fifth, crops have irregular growth and their performance varies. Sixth, the stems became thinner and the plants changed from normal triangles to trapezoidal trapezoids at the top.
If strawberries, cucumbers, tomatoes, and eggplant are cultivated in the same plot, the first victim is the strawberry; with the increase in soil concentration, the cucumber is then victimized; if the concentration is higher, tomato growth will also be hindered. The eggplant's salt tolerance is relatively strong.
In the conditions that can accurately identify whether the soil is salty or salty, the problem of soil salt-endangering vegetables can be prevented and solved.
The most fundamental way to prevent soil salinity is to adhere to the application of organic fertilizers, scientific and rational use of chemical fertilizers, pay attention to the application of multi-element composite special fertilizers, such as potassium sulfate compound fertilizer, humic acid compound fertilizer, microbial fertilizer, etc. Available nitrogen fertilizer is strictly prohibited. The second is to select those chemical fertilizers that have a small increase in concentration of soil solution after application to the soil, such as lime nitrogen, ammonium nitrate, and superphosphate. Once soil salinity occurs, in addition to scientific fertilization, active measures should be taken to eliminate salt damage. The specific methods are as follows:
First, the use of flooded high-temperature treatment during the summer relaxation period has both the role of eliminating salt damage and killing pathogens in the soil.
Second, plant corn in summer, absorb the available nitrogen in the soil in excess, and then press green in due course, using the large number of breeding microorganisms in the process of green body decomposition to further consume excess available nitrogen.
Third, out of the topsoil or change to new soil, or cover the ground with a thin layer of earth. However, this method of changing soil requires a lot of labor, and it is generally used only when it is necessary.
In the summer, the reclamation of the cofferdam introduced runoff and the salt was washed with large water.
5. The appropriate time (preferably a rainy season) can be selected during the year to lift the roof membrane of the greenhouse to allow the soil to be washed and washed with rain so that the salt on the surface of the soil or the surface soil layer is washed away.
Six, mulch film coverage can also play an ideal role in the reduction of soil salinization.
If the problem of soil salinity, soil-borne diseases, and underground pests is serious, high-temperature flooding can be considered during the summer.
Due to the high temperature and raininess in summer, planting production is generally not carried out, which leaves time for high-temperature flooding. In the summer relaxation period, the treatment of soil with hot water at high temperature can not only kill nematodes, but also eliminate a large number of soil-borne pathogens, and effectively reduce soil salt content. Therefore, high-temperature flooding treatment is an agricultural measure with multiple functions and effects. At the same time, it is a pollution-free technology that does not have adverse effects on crops and the environment. Therefore, it should be strongly advocated for use.
The practice of flooding high temperature treatment is:
1. Remove the plant debris from the shed; 2. Apply 200 kg of quick lime per acre and adjust the soil to be alkaline; use 500-1000 kg of straw or wheat straw or sawdust per acre and evenly spread it to the surface; - 60 cm, 30 cm higher ridge;
Fourth, pouring large water in the ditch to keep the water in the ditch;
Fifth, on the surface generally covered with plastic film, while the greenhouse and greenhouse should be closed as much as possible, so that the ground temperature at 20 cm above 50 °C, continuous maintenance for 15-20 days. After high-temperature treatment, spread 2-3 kg of 50% carbendazim WP or 50% carbendazim WP and 50% DM WP mixture equivalent to 3-4 kg per acre.