Greenhouse vegetables are a kind of economic crops with annual production, high annual multiple cropping index, large amount of fertilizers, high inputs, and high yields, so that non-technical levels directly affect the yield and quality of vegetables, thereby affecting human health and soil. The deterioration of the environment has affected the sustainable development of greenhouse vegetables.
Problems with greenhouse vegetables
1, excessive application of nitrogen fertilizer, potassium fertilizer application amount is insufficient. At present, the practice of reusing nitrogenous fertilizers is common in greenhouse vegetable production. Some vegetable growers are blindly obsessed with large and dark green leaves and strong plant growth, while ignoring the imbalance of nutrients in the soil during late flowering, fruit setting and fruiting. The relative shortage of potassium, calcium, and magnesium caused some of the crop's physiological diseases, such as tomato rot, and umbilical rot. At the same time, excessive nitrogen fertilizer causes a large accumulation of nitrate in the soil, increasing the content of soluble salts in the soil, and even causing salt damage.
2. The accumulation of salt in the soil of the greenhouse increases and salt is formed. Greenhouse vegetable cultivation is pursuing high yield because of its purported high yield. The amount of fertilizer is generally larger and much higher than that of open field cultivation. Excessive application of chemical fertilizers will cause large amounts of salt to dissolve in the soil. At the same time, greenhouse semi-enclosed environmental conditions prevent the leaching of soil moisture. , Salt accumulation in the soil, the formation of secondary salinization of the soil in the cultivation layer, affecting the yield and quality of vegetables, reducing the use of greenhouse facilities.
3, do not pay attention to the application of calcium, magnesium and trace elements in vegetables. Vegetables not only need to absorb large amounts of nitrogen, phosphorus and potassium, but also absorb more calcium and magnesium. At the same time, trace elements can not be lacking, otherwise it will affect its growth and development. Due to insufficient understanding of this, vegetable farmers neglected the application of medium and trace element fertilizers. Some of them only rely on organic fertilizers to supplement them. As a result, the medium and trace elements in the soil tend to decrease with increasing shelf age, especially calcium, magnesium, and boron. Such as the lack of serious, such as soil sheds, can induce a variety of diseases, celery stem disease, tomato rust stains, cucumber peel longitudinal cracks.
4. Soil organic matter is relatively low. Most vegetable growers use organic fertilizers in small quantities, some of which are larger, but most of them are not decocted and will increase soil salt content. The average soil organic matter content in China's history and literature is about 30%, and there is still a gap between 4%-5% of the organic matter content in the greenhouse, and the Netherlands, Japan and other countries with a higher level of greenhouse development (greenhouse soil organic matter content is generally 6%-7%). The difference is far away.
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