For the old greenhouses, the most prominent problem is soil salinization, and the most prominent cause of soil salinization is long-term, large-scale application of chemical fertilizers. Older greenhouses are poorly insulated and are prone to rooting in the winter and early spring. Therefore, old greenhouses should pay attention to the selection of microbial fertilization or humic acid, all water-soluble fertilizer and other fertilizers, both to alleviate soil salinization but also help to improve the temperature. Select biological fertilizer. Biofertilizer can release the fixed nitrogen, phosphorus and potassium in the soil and promote the improvement of soil fertility. The use of biological fertilizers in older greenhouses is more effective. In order to ensure that vegetables absorb enough nutrients, it is recommended that vegetable growers use biofertilizer and compound fertilizers in rotation. Choose humic acid fertilizers. Because of the high nutrient content of N, P and K in old greenhouses, humic acid fertilizer can increase the utilization of P and K and some trace elements in the soil. Humic acid fertilizers have a synergistic effect on phosphorus and potassium. Based on the application of humic acid fertilizers, the amount of chemical fertilizers can be appropriately reduced, and generally can be reduced by about 1/3. The humic acid fertilizers commonly used in vegetable production include nitrohumic acid, ammonium humate, sodium humate, potassium humate, potassium nitrohumuvate, diammonium fulvic acid, phosphoric acid fulvic, etc. Friends can choose to apply. Select full water soluble fertilizer. The total amount of water-soluble fertilizer is small, and only 10 to 15 pounds can be used for a greenhouse with an acre of land, and the utilization rate is as high as 85%. It can supplement the nutrients needed for crops, and it is worthwhile to promote the rotation in winter with biological bacterial fertilizers. Fertilizer way.
