How to fertilize greenhouse vegetables? These points you need to know

Growing vegetables in a greenhouse differs from conventional open-field cultivation. If fertilization is not done in a scientific way, it will not only affect the yield and quality of greenhouse vegetables, but also cause salinization of the greenhouse soil. Therefore, fertilizing greenhouse vegetables requires great care, and the following five points should be noted:

1. Apply more organic fertilizer. Organic fertilizer can improve soil structure, increase the content of soil organic matter, and produce carbon dioxide during decomposition, which is very beneficial to the growth and development of greenhouse vegetables, increasing yield and improving quality. Generally, no less than 5000 kg of high-quality organic fertilizer should be applied per mu, and as much hot-fermenting manure as possible should be applied, such as mule manure, horse manure, sheep manure, etc.

2. Choose suitable types of chemical fertilizer. Because greenhouse soil is not affected by rainfall, salts cannot be lost with rainwater or leached into the deeper soil layers. If fertilizers such as ammonium sulfate, potassium sulfate, and potassium chloride are applied to the soil, they will decompose into sulfate ions, chloride ions, etc. These ions are not easily absorbed and utilized by crops, but remain in the shallow soil layer, raising the concentration of the soil solution and affecting the growth and development of vegetables and reducing quality. Therefore, when applying chemical fertilizers to greenhouse vegetables, it is advisable to choose diammonium phosphate, ammonium phosphate, ammonium nitrate, superphosphate, urea, potassium dihydrogen phosphate, etc.

3. Do not apply fresh human excrement and urine. After fresh human excrement and urine are applied in a greenhouse, because the temperature inside the greenhouse is relatively high, the fresh human excrement and urine will quickly decompose and rot. The urea and inorganic salts produced in the initial stage will increase the concentration of the soil solution, thereby affecting the absorption of water and nutrients by vegetables. Fresh human excrement and urine can also produce a large amount of ammonia gas, poisoning the vegetables and then causing seedling burn. In addition, fresh human excrement and urine also contains pests and diseases harmful to human health, and direct use will affect human health. Therefore, human excrement and urine must be fermented and decomposed for 8-10 days before application.

4. Nitrogen fertilizer should be applied deeply. Nitrogen fertilizer should be applied deeply and covered with soil. This can reduce the opportunity for contact with air and avoid the volatilization of nitrogen fertilizer. At the same time, deep application of nitrogen fertilizer can also reduce the accumulation of sulfate in vegetables and improve the utilization rate of nitrogen fertilizer. Generally, the application depth of nitrogen fertilizer should be below 10-14 cm, and the soil should be covered immediately after application.

5. Chemical fertilizer should be applied in an appropriate amount. Applying too much fertilizer to greenhouse vegetables at one time not only causes waste, but also increases the salt concentration of the soil, causing nutrients to flow backward and harming the vegetables. The amount of fertilizer applied to greenhouse vegetables should be flexibly controlled according to differences in soil type, vegetable variety, etc. Generally, the amount of chemical fertilizer applied per mu at one time is: ammonium nitrate 15 kg for sandy loam, 18 kg for loam or clay; urea 10 kg for sandy loam, 12 kg for loam or clay; basal application of superphosphate 40 kg for sandy loam, 15 kg for loam and clay; diammonium phosphate 25 kg for sandy loam, 35 kg for loam and clay. Liu Shengwu