Good application rate of reducing base fertilizer for greenhouse vegetables

First of all, the greenhouse is a closed facility, indoor harmful gases are not easy to eliminate, such as excessive use of base fertilizer, more volatile ammonia, indoor vegetables suffer from ammonia harm, so that the dry edge of leaves or withered spots, serious leaf withering, until the occurrence of dead trees.

Second, before entering the flowering and fruiting stage, the amount of fertilizer absorbed by vegetables is only about 1 / 6 of the total amount of fertilizer absorbed in the whole growth period. in this period, there should not be more soil fertilizer, which will not only cause the phenomenon of burning seedlings, but also cause the seedlings to flourish and affect the flower bud differentiation. delay the fruiting period.

Third, greenhouse vegetables due to a large amount of fertilizer for a long time, there is no lack of various nutrients in the soil, what is lacking is carbon dioxide. However, the demand for carbon dioxide of crops in the seedling stage is very small, it gradually increases with the increase of the number of leaves, and the demand for carbon dioxide reaches the peak in the peak fruiting period. The carbon dioxide in the greenhouse mainly comes from the decomposition of organic fertilizers in the soil. After the organic fertilizers are applied into the soil, the peak period of carbon dioxide release is about 10 to 50 days after fertilization. The application of a large amount of base fertilizer will not only cause the phenomenon of burning seedlings, but also the release of carbon dioxide is wasted because the amount of carbon dioxide used in the early stage of crop growth is very small. After entering the fruiting period, the amount of carbon dioxide needed increased, but the peak period of carbon dioxide release in the soil has passed, and the supply of carbon dioxide is insufficient, which restricts the exertion of photosynthetic efficiency and affects the improvement of yield.

Therefore, the use of base fertilizer should not be too much, generally apply 2500-3000 kg base fertilizer per mu. A large number of organic fertilizers should be applied in stages after flowering and fruiting in order to continuously provide sufficient carbon dioxide for crop photosynthesis.