Improved Crop Management Achieved High Wheat Yield and Nitrogen Use Efficiency

Abstract

Approaches to meet increasing demand for cereals while improving agricultural resource use efficiency have been extensively studied. However, the dominant intensive agricultural paradigm still considers high yield and increased nitrogen use efficiency (NUE) to be contradictory goals. The objective of this study was to determine whether increased yield requires a proportional increase in N application. Two groups of N treatments were compared at 33 field sites in four wheat producing provinces of China. With a high-yield system (HY), the average yield, PFPN and AEN were 42.3, 37.6 and 38.7% higher than current farming practice (CP), respectively. The average estimated maximum grain yield for HY was 8563 kg ha–1 over 2 years, 2007 and 2008, which was 44.2% higher than under CP (5938 kg ha–1). The optimal N rate for HY was 185 kg ha−1, which was significantly higher than that under CP (149 kg ha−1). The increased wheat yield with HY was accompanied by 24.1% increase in optimal N rate. Significant relationships were found between 0-N (unfertilized control) yield and the estimated maximum yield and AEN with HY and CP. There were also decreasing trends for PFPN and AEN with increasing N rate in HY and CP. These on-farm observations indicate that achieving increased yield does not require a proportional increase in the amount of N fertilizer, which provides a win–win opportunity to meet food demand while improving NUE.