What is the harm of excessive application of organic fertilizer to vegetables?

What is the harm of excessive application of organic fertilizer to vegetables? How to prevent excessive application of organic fertilizer? We also ask experienced netizens to introduce that organic fertilizer can improve the physical and chemical properties of soil, enhance the performance of water and fertilizer conservation, and improve the ability of sustainable fertilizer supply, but excessive application of organic fertilizer will also affect the physical and chemical properties of soil, and in serious cases, it will cause soil salt accumulation and affect crop growth. And excessive input of organic fertilizer will also cause nitrate accumulation in vegetables. More seriously, excessive application of organic fertilizers such as municipal solid waste polluted by heavy metals will also cause heavy metal pollution in soil and vegetables. Therefore, the farming network has sorted out the methods of reasonable application of organic fertilizer, which are listed in detail below for netizens' reference. First, choose high-quality organic fertilizers: high-quality organic fertilizers are the basis for high quality and high yield of vegetables, but now most of the organic fertilizers used by vegetable farmers are commercial fertilizers bought, and the quality is generally low, and some are even mixed with municipal sludge, domestic waste, and so on. it can't meet the standard of organic matter content at all. Even some bought chicken manure is mixed with soil, or has been mixed with fire alkali by some illegal traders (to increase the volume). After these inferior organic fertilizers are applied to the soil, the effect can be imagined. Therefore, high-quality organic fertilizer must be selected in production, and it is best to choose the one produced by regular large manufacturers when selecting commercial organic fertilizer. Second, strictly control the application amount of organic fertilizer: since more application of organic fertilizer is harmful than beneficial, we should control its amount in the future production, so how much should be applied per mu of vegetable field to meet the needs of vegetable production? The author thinks that, in general, it is suitable to apply 1520 square meters of pure chicken manure and 3540 square meters of rice husk manure per mu of vegetable land, and the fertilizer amount of eggplant fruit manure vegetables can be taken as the upper limit. The amount of fertilizer required for leafy vegetables is slightly smaller, and its lower limit can be taken. Third, cooperate with the application of biological fertilizer: no matter the basic application or flushing application of organic fertilizer, it is best to use it with biological fertilizer. Why cooperate with biological fertilizer? Because after the application of organic fertilizer in combination with biological fertilizer, the biological bacteria in biological fertilizer can accelerate the decomposition of organic matter in organic fertilizer, make it more beneficial to crop absorption, and at the same time decompose and transform some harmful substances in organic fertilizer to avoid causing harm to vegetables. Therefore, in the basic application of organic fertilizer, the combined application of biological fertilizer can be 150 kg / mu and 200 kg / mu, and the combined application of biological fertilizer 20 kg / mu and 25 kg / mu can achieve better results. Methods for determination of soil acidity and alkalinity improvement methods for acidic soils