Air Hazard Ammonia is easy to enter from the stomata and water holes of vegetable leaves, causing alkaline hazards in plants. The leaves of the affected crops were initially water-soaked, then gradually turned light brown, and the young buds or growth points shrank, becoming black. In severe cases, the leaf margins were scorched, and the entire plant lost water and shrank to death. There are four causes of damage: one is the application of inadequately decomposed manure; the other is the fermentation of cake or chicken manure in the greenhouse; the third is the application of fertilizer to the ground when the fertilizer is applied; the fourth is the uneven application of the fertilizer. Harmful by ammonia.
Fertilizer Application of a single chemical fertilizer or excessive application of chemical fertilizers or commercial organic fertilizers to the soil results in excessive soil solution concentration and reverse osmosis, which results in the inhibition of vegetable root development, plant wilting or defoliation of the leaf edges, and deficiencies. .
The first one is the dominant one, the symptoms are obvious; the second one is the hidden one, the symptoms are latent or delayed. After the pesticide damage occurs, the leaves of the vegetables become green or cause focal spots, perforations, fallen leaves, falling flowers, falling fruits, and even the entire plant withers. There are four reasons for the damage: First, the pesticides are wrong or the herbicides are misused; second, the application concentration is too high; third, inferior pesticides are purchased; and fourth, the drugs are used at high temperatures.
Drought drought not only affects vegetable seedlings, but also affects vegetable growth and development, and causes difficulties in fertilizing and using drugs. There are three causes of damage: First, the greenhouse is not properly selected and lacks water; second, the water quality is poor; third, the drainage channels and drainage and irrigation facilities are not complete, and it is difficult to draw water.
The stubble hazard refers to the same or the same type of vegetables grown in the same greenhouse every year or season, the yield and quality of which decline year by year. There are three causes of damage: first, the same or the same kind of vegetables prefer a certain nutrient element, and when the required elements are not supplemented in time, harm will occur; second, the accumulation of soil pathogens causes the disease; third, the root exudates cause the imbalance in the soil microbial community structure , Soil aging.
There are four countermeasures:
Before selecting a shed for a perfect water system, you should fully consider whether there are sufficient and excellent water sources. Ditches should be opened to facilitate water diversion and drainage. Where conditions permit, a faucet can be installed in each greenhouse, and high-standard ones can also be equipped with sprinkler irrigation facilities.
Reasonable fertilization to promote the healthy growth of vegetables. One is to apply fully decomposed farm organic fertilizers throughout the year. The other is to use refined and high-energy commercial organic fertilizers, bio-organic fertilizers, and bio-organic compound fertilizers. , Potassium increase, combined with application of micro-fertilizer; four is the appropriate amount of fertilization; five is the application of 0.01% of Baoliang (brassinolide) or Hongliang (microbial agent) 800 times liquid once the fat appears; 2 ~ 3 times.
Scientific use of medicines to ensure the safety of vegetables. One is to strengthen the management of fertilizers and water to restore the normal growth function of vegetables when minor phytotoxicity occurs. The second is to use appropriate pesticides, especially herbicides. The third is to control the dose and concentration of pesticides to avoid them. Repeated application of a pesticide; Fourth, do not mix pesticides randomly; Fifth, avoid high temperatures; Sixth, clean the instruments after applying the herbicide before reuse.
Rotating crops to adjust the cultivation environment First, susceptible vegetables such as eggplants, tomatoes and melons should be replaced every year or season; second, organic fertilizer should be added to greenhouses that are prone to stubble obstacles to improve soil; The soil replanting agent inhibits germs; the fourth is to target nutrient-deficient soils and timely supplement the lacking nutrients. (Yu Hongzhang)
Link: "Seven Don'ts" for Fertilizing Greenhouse Vegetables in Winter
Many vegetable farmers in the greenhouse vegetable cultivation often apply fertilizer blindly and apply fertilizer, which not only fails to produce high yields, but also causes damage to the soil and crops. Recently, how to scientifically use fertilizer in greenhouse vegetables, the reporter interviewed the soil fertilizer of Gansu Academy of Agricultural Sciences And Zongxian Che, director of the Institute of Water-saving Agriculture.
Do not apply ammonium sulfate. Ammonium sulfate is a physiological acid fertilizer. After application, it will increase the acidity of the soil, damage the soil structure, and adversely affect the growth of vegetables.
Do not apply uncured cake fertilizer cake fertilizer. The carbon-nitrogen ratio of the cake fertilizer is small, it decomposes quickly, it is easy to produce high temperature and high concentration of ammonia and organic acids, and it is easy to burn the root. The cake fat should be broken up and used after high temperature fermentation.
Do not fertilize vegetables under drought conditions. Water-loving crops. Fertilizing when soil is dry, not only does the fertilizer effect not be fully exerted, but it also causes the soil solution concentration to rise suddenly, and it is easy for the vegetables to burn their roots. Therefore, fertilization of vegetables should be combined with irrigation, and furrowing can be applied, and the fertilizer can be irrigated after burying the fertilizer tightly, or the fertilizer can be topped down.
Do not over-apply diammonium phosphate. Vegetables require a large amount of nitrogen and potassium, and relatively less phosphorus. Phosphate fertilizers are not suitable for dispersed application in vegetable greenhouses. Phosphorus is easily absorbed and solidified by the soil and loses its fertilizer effect. Therefore, phosphate fertilizer is suitable for basal fertilizer or concentrated application in the soil layer with dense root system in the early stage of vegetables. It should be noted that diammonium phosphate should not be mixed with alkaline fertilizers such as plant ash to avoid causing ammonia volatilization and ammonia harm.
Do not apply chlorine-containing fertilizers. Chloride ions can reduce the starch and sugar content of vegetables, degrade the quality of vegetables, reduce the yield, and the residual chloride ions in the soil can cause soil acidification and easily cause soil decalcification.
Do not apply iron fertilizer to the soil. Iron is easily fixed by the soil into insoluble compounds and loses its fertilizer effect. Iron does not flow easily on the leaves. It should be applied by foliar spray. Dilute ferrous sulfate solution can be evenly sprayed on vegetable leaves. Surface.
Do not apply the rare earth micro-fertilizer directly to the soil. The rare earth micro-fertilizer solution can be sprayed on the leaf surface of vegetables, and it can spray about 60 kilograms per mu.
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