Why does paddy field emphasize more application of organic fertilizer?

Paddy fields are planted year after year, constantly absorbing a large amount of nitrogen, phosphorus, potassium and a certain amount of calcium, magnesium, sulfur, iron and other elements from the soil, but also absorb a small amount of chlorine, zinc, manganese, boron, copper, molybdenum and other trace elements. In addition, rice absorbs about 10 times as much silicon as chlorine. A large number of nutrients are absorbed and some of them are leached. The supplement of inorganic fertilizers alone can not meet the needs of rice production. Therefore, it is necessary to implement the combined application of organic and inorganic fertilizers. The application of organic fertilizer can not only directly provide a variety of rich nutrients for rice, but also humus part of organic matter and synthesize soil humus in the process of decomposition of organic matter by soil microorganisms. this plays an important role in improving soil physical properties and structure, increasing the quantity and quality of soil colloid, and improving soil fertilizer conservation and supply capacity. In addition, some delayed phosphorus and potassium in paddy soil can be activated in the process of organic matter decomposition, and various physiologically active substances such as vitamin B and auxin can be produced to promote the growth of rice.