What should I do if there is salt damage in vegetable fields? Vegetable salt damage generally occurs in greenhouse cultivation and inappropriate fertilization methods. For the improper application of fertilization, as long as the scientific fertilization method is mastered, the occurrence of vegetable salt damage can be avoided. For the greenhouse soil, if the secondary salinization is harmful to the vegetables, the whole plant will die and the whole shed will be rejected.
1 Salt damage performance
After cultivating vegetables for many years in greenhouses, due to the large amount of water, poor water quality, large amount of chemical fertilizer application, and application of human excrement for many years, it is easy to cause an increase in soil salinity, which is characterized by soil salinization, that is, secondary salt. Generally, white salt spots and salt flowers appear on the surface of the saline soil, and even copper cyan or brown salt spots appear. When the soil salinization in the greenhouse occurs seriously, the vegetables usually show short plants, light leaves, and waxy leaf margins; shallow roots, few lateral roots, thin root hair and rust color; low yield and low quality in late stage, and dead plants in severe cases The whole shed is not harvested.
2 Cause
The vegetables are cultivated under the conditions of greenhouse, the temperature in the shed is high, and the evaporation of soil moisture is large, so that the salt in the lower soil rises to the surface layer of the soil through capillary action, causing the salt to accumulate on the soil surface. At the same time, the number of vegetables in the greenhouse More, high yield, large amount of fertilizer, resulting in a large amount of unabsorbed fertilizer accumulated in the soil, resulting in increased salt concentration. In addition, shallow cultivation in the greenhouse, pouring fertilizers into the topsoil and other cultivation measures have intensified the concentration of salt in the surface. According to the investigation, the soil in the greenhouse that has been planted for more than 3 years has different degrees of salt damage.
3 Comprehensive prevention
3.1 Scientific irrigation
First, it is necessary to irrigate according to the water demand of each vegetable in the growing period of the greenhouse. Secondly, water quality should be tested for irrigation water, and water with a large salt content cannot be used. In conditional irrigation, it is best to promote micro-drip irrigation technology, which can directly spray water directly onto the root of the plant through pipes and micro-dropholes, which reduces the leakage of water and facilitates the uniform application of fertilizer with water.
3.2 Improve soil and increase soil permeability
Soils with heavy texture must be sanded for improvement. At the same time, organic fertilizer should be added in large quantities to increase soil organic matter content, improve soil aggregate structure, improve soil fertility and water retention capacity, and appropriately reduce irrigation amount.
3.3 Using scientific formula fertilization
It is recommended to use the principle of fertilization supplemented by organic fertilizer, supplemented by chemical fertilizers, nitrogen, phosphorus and potassium, and formulate fertilization. In addition, the fertilizer type and fertilization method should be correctly selected, and the fertilizer without negative component should be applied as much as possible. Such as urea, potassium nitrate, calcium phosphate, diammonium phosphate and the like. Formulated fertilization and on-demand supply can significantly reduce the residual accumulation of salt in the soil. Extend the soil life in the greenhouse.
3.4 Adding organic fertilizer and biological fertilizer
Add organic fertilizers, such as green manure, composting compost, and manure to improve soil structure and increase soil fertility. It is recommended to increase the application amount of organic fertilizer in the base fertilizer and apply a certain amount of biological fertilizer. Combined with deep turning, it can improve soil structure, improve soil permeability, activate soil, increase ground temperature, and facilitate the extension of lateral roots of vegetable crops. Increase the ability of roots to absorb water and nutrients and increase their resistance to salt. Due to the addition of organic fertilizer and biological fertilizer, the amount of chemical fertilizer can be appropriately reduced, which not only increases the soil organic matter content, but also reduces the residual accumulation of salt in the soil. In particular, organic fertilizer must be stacked for 3 to 4 months, and fully fermented before being applied in a solar greenhouse.
3.5 Extend the natural rainfall leaching time
It is recommended that the film on the top of the greenhouse be removed as early as possible from the end of June to the end of September to allow the natural rainfall during the rainy season to fully leaching the soil and reduce the concentration of salt in the soil.
3.6 Biological Desalting
Planting Sudan grass can absorb excess salt from the soil, which is one of the better methods to solve the secondary salinity of greenhouse soil. In addition, the desalination effect of corn is also good.
3.7 Anti-salt exercise
Improve the salt tolerance of vegetables. After soaking the seeds before sowing, soaking them with 0.6% saline solution for 6 to 12 hours can significantly improve the salt tolerance. The seedling stage has the worst pressure resistance. Spraying 50 mg/kg of gibberellin can stimulate the growth of vegetables, dilute the salt concentration in the body, and enhance its salt tolerance.
3.8 Film mulching
In the production season, the method of watering the film under the film is used to reduce the evaporation rate of the soil surface, thereby slowing the rate of deep salt rise in the soil.
3.9 Choose salt-tolerant vegetables
Production practice shows that the roots of different kinds of vegetables have different tolerance to soil salt concentration, and the resistance of eggplant is stronger, followed by tomato and pepper, and again to zucchini and cucumber.
In addition, appropriate measures to replace the surface soil of the greenhouse, and the promotion of vegetable organic ecological soilless cultivation techniques can effectively prevent soil salinization in greenhouses and reduce or avoid salt damage.
Therefore, effective measures must be taken in the cultivation and production of vegetable greenhouses to prevent the occurrence of secondary salt in the greenhouse soil and overcome the impact of salt damage. The salt hazards of such greenhouse vegetables will be reduced to a minimum, and more agricultural technology knowledge will be available in Huinong.com!
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