Yield and nutrient balance of lettuce as influenced by reduced and optimized nitrogen application
氮肥优化减施对土壤-莴苣系统氮磷平衡及产量效益的影响

Environment and health quality of vegetable are closely related with food quality and human health.Most farmers use excessive chemical fertilizers to maximize yield.This practice,along with high irrigation and multiple cropping,results in soil degra-dation,nitrogen(N)/phosphorus(P) loss,and other severe environmental issues.A field experiment was carried out in a vegetable field of suburban Changsha City to determine the effects of reduced and optimized application of N fertilizer on soil nutrient balance a...