Research progress on collocation planting of crops for decreasing the loss of soil nitrate nitrogen through leaching

In order to obtain the higher crop yield, the more fertilizers were applied to the soil. At the same time, unreasonable field management measures cause massive nitrate nitrogen accumulation in soil, which leads to a risk to the ground water due to N leaching. Collocation planting of different types of crops is one of the effective cultivation strategies to increase crops yield and improve utilization of photo-thermal resources, and simultaneously reduce soil nitrate nitrogen loss through enhancing soil nutrient use efficiency. Collocation planting patterns of different types of crops (such as facility vegetables and catch crops, grain crops and economic crops, grain crops and grain crops, grain crops and outdoor vegetables, vegetables and vegetables) were introduced in this paper. And, the effects of different collocation planting patterns on soil N utilization, reduction of accumulation and leachate of soil nitrate nitrogen were discussed too. The mechanisms were explained from the characteristics of different crops. Finally, some research prospects in the future were put forward on the planting patterns. It was suggested that studies on root system of collocation planted crops was the breakthrough point.