Quantitative Relationship Between Nitrous Oxide Emissions and Nitrogen Application Rate for a Typical Intensive Vegetable Cropping System in Southeastern China

• Published in: Clean : soil, air, water Vol. 44; no. 12; pp. 1725 - 1732
• Main Authors: Zhang, Man, Chen, Zhao Zhi, Li, Qiao Ling, Fan, Chang Hua, Xiong, Zheng Qin
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01.12.2016; Wiley Subscription Services, Inc
• Subjects: Emission factor; N2O; Response curve; Vegetable; Yield-scaled emission; China, People's Rep
• ISSN: 1863-0650; 1863-0669
• DOI: 10.1002/clen.201400266

To explore the mechanism underlying the relationship between nitrous oxide (N2O) emissions and different nitrogen (N) application rates, we conducted a 2‐year‐round field experiment comprising seven vegetable crop seasons by using static chamber‐gas chromatographic techniques in a continuously cultivated vegetable cropping system in Southeastern China. The results showed that N application significantly affected the N2O emissions. The cumulative N2O emissions amounted to 16.9 ± 1.9, 25.2 ± 2.2, 30.0 ± 1.9, 36.7 ± 1.5, and 48.1 ± 2.2 kg N ha−1 y−1 for the five N application rates at 0, 370, 740, 1110, 1480 kg N ha−1 y−1, respectively. Both linear and exponential relationship was observed between cumulative N2O emissions and N application rates. The emission factors ranged from 1.8 ± 0.1 to 2.3 ± 0.6% and averaged 2.0 ± 0.3%. The treatment receiving 2/3 of the conventional N fertilizer amount led to the lowest yield‐scaled N2O emissions. Therefore, according to this study the recommended N application rate should be reduced by one‐third for N2O mitigation while enhancing vegetable production in Southeastern China. During the 2‐year field observation, both linear and exponential relationships are observed between total N2O emissions and N application rates even within a high N rate range of 0–1480 kg N ha−1 y−1. Based on the yield‐scaled N2O emissions, we recommend a one‐third reduction in N fertilizer for the current vegetable production.