Trace elements include boron, zinc, molybdenum, iron, manganese, copper and other nutrients. Although the plant's demand for trace elements is small, their role in the growth and development of plants is as important as that of macroelements, when a certain trace element is deficient, the growth and development of crops is significantly affected, the yield is reduced, and the quality is reduced. On the other hand, too much trace elements can poison crops, affect yield and quality, and even endanger human and animal health in severe cases. With the continuous improvement of crop yield and the large application of chemical fertilizers, the application of trace element fertilizers is gradually urgent. In trace element fertilizers, iron, manganese, zinc, copper sulfate, boric acid, molybdate acid and their monovalent salts are usually used.
