SUSTAINABLE NITROGEN MANAGEMENT FOR VEGETABLE PRODUCTION IN CHINA

Inappropriate nitrogen fertilizer management for the intensive Chinese vegetable production has caused low N use efficiency(NUE),high reactive nitrogen(Nr)losses and serious environmental risks with limited yield increase.Innovative N management strategy is an urgent need to achieve sustainable vegetable production.This paper summarizes recent studies on Nr losses and identifies the limitations from Chinese vegetable production systems and proposes three steps for sustainable N management in Chinese vegetable production.The three N management steps include,but are not limited to,(1)knowledge-based optimization of N fertilizer rate strategy,which maintains soil N supply to meet the dynamic vegetable demand in time,space and quantity;(2)innovative products and technology,which regulates the soil N forms and promotes the vegetable root growth to reduce the Nr loss;(3)integrated knowledge and products strategy(IKPS).The knowledge-based optimization of N fertilizer rate strategy and innovative products and technology,can maintain or increase vegetable yield,significantly improve NUE,and mitigate the region-specific and crop-specific Nr losses.More importantly,IKPS,based on combination of in-season root-zone N management strategy,innovative products and technology,and best crop cultivation management,is needed to produce more vegetables with lower Nr losses.