Trace elements include zinc, boron, molybdenum, manganese, iron and copper. Are necessary for crop growth and development, just because crops need very little of these elements, so they are called trace elements. Trace element water soluble fertilizer plays an important role in promoting and regulating the synthesis, photosynthesis or metabolism of chlorophyll and protein, as well as the absorption and utilization of nutrients such as nitrogen, phosphorus and potassium. Although crops need less trace elements, the application of corresponding micro fertilizer in nutrient deficient or potentially nutrient deficient soil can greatly improve the yield of crops and the quality of agricultural products.