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1. To determine the amount of economic fertilization, select suitable fertilizer varieties, determine the appropriate fertilization period, fertilization methods and so on. According to the premise of determining the amount of fertilizer to meet the demand of vegetables, it should be calculated according to the yield level and soil fertility level. For example, if the supply of nitrogen, phosphorus and potassium nutrients in the soil can meet the needs of vegetables, to ensure the fertilization intensity, according to the vegetable yield of 20%~ 40% of the amount of fertilizer applied. At present, the level of fertility should be controlled by nitrogen, phosphorus, and potassium, and the application of micro-fertilizer is the principle of fertilization.
It is generally not advisable to use chlorine-based fertilizers. It is not advisable to use volatile nitrogen fertilizers and try to control nitrate-nitrogen fertilizers. Generally, the vegetables with short growth period or roots, stems and leaves are harvested. 12% to 13% of nitrogen fertilizer, all phosphorus, potassium and micro-fertilizer can be used as base fertilizer, and the other nitrogen fertilizer is applied as top dressing in the growth stage. The melons and fruits can be applied with 13% nitrogen fertilizer, 23% phosphorus and potassium fertilizer, and all micro-fertilizer as base fertilizer, and the other nitrogen fertilizer and phosphorus-potassium fertilizer are applied as top dressings. If the salt content is between 0.2% and 0.3%, it is not appropriate to apply chemical fertilizer as the base fertilizer.
2. Re-apply organic fertilizer and deep-plow the soil in a year-round manner. The fertilized high-quality organic fertilizer is selected for the base fertilizer application about 1 month before the cover shed. The application amount is generally l~1.5 times of the field, that is, 3000-10000 kg per mu, and the deep tillage is carried out year by year, and the tillage layer is thickened. Soil and fertilizer blend together to improve the physical and chemical properties of the soil.
In order to prevent poisoning of ammonia and nitrous acid gas, application of organic fertilizer should be decomposed, especially chicken manure, requiring high degree of maturity and early application. It is strictly forbidden to stack in the shed for a long time. Organic fertilizer and inorganic fertilizer can be applied together. If a part of inorganic fertilizer is extracted for foliar spraying, it is more economical.
3. For better soils, choose a better irrigation method. Different vegetables have different requirements on soil moisture. The roots are shallower vegetables such as cucumber, pepper, broccoli, celery, lettuce, etc., like moist soil, the amount and frequency of irrigation are increased appropriately, and the roots are deep into soil such as watermelon, melon, loofah and tomato. The zucchini and other drought tolerance are strong, and the amount of irrigation and the number of irrigation should be minimized. Different growth periods have different requirements on soil moisture. The roots have weak water absorption capacity at seedling stage, and the soil moisture is required to be high. The roots should be controlled by water and seedlings to promote roots. At the peak of the period, the wet vegetables should be watered and the topsoil should be relatively The humidity is maintained at about 85%; for drought-tolerant vegetables, it is not advisable to supply too much water during this period.
In the plastic greenhouse, how to determine the appropriate irrigation period, irrigation temperature, irrigation amount and irrigation method is the key to achieve reasonable irrigation. For greenhouse irrigation water, the water temperature should be maintained at 20 °C ~ 25 °C, more than 28 °C will damage the vegetable roots, causing greenhouse vegetable diseases.
4. Effectively solve salt damage. For plots where salt damage has occurred, it can be solved by applying organic fertilizers by selecting salt-tolerant vegetables such as cabbage, spinach, pumpkin, celery and broccoli. It is also very effective to change soil to remove salt or water.
In greenhouses and plastic greenhouses, the concentration of salt in the soil is constantly rising due to excessive fertilization and no natural precipitation. Standardized fertilization is an effective way to prevent the accumulation of salt in the greenhouse.
In the cultivation of off-season vegetables, not only plastic greenhouses, solar greenhouses and other hardware facilities are in place, fertilization technology is also critical. There are still some differences between anti-seasonal vegetables and seasonal vegetable fertilization methods. After practice, the key points of anti-season vegetable fertilization techniques are now introduced:
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