Nitrate leaching, direct and indirect nitrous oxide fluxes from sloping cropland in the purple soil area, southwestern China

摘要

This study provides a combined dataset on N loss pathways and fluxes from sloping cropland in the purple soil area, southwestern China. A lysimeter experiment was conducted to quantify nitrate leaching (May 2004-May 2010) and N_2O emission (May 2009-May 2010) losses. Nitrate leaching was the dominant N loss pathway and annual leaching fluxes ranged from 19.2 to 53.4 kg N ha~(-1), with significant differences between individual observation years (P < 0.05). Direct N_2O emissions due to N fertilizer use were 1.72 ± 0.34 kg N ha~(-1) yr~(-1) which corresponds to an emission factor of 0.58 ± 0.12%. However, indirect N_2O emissions caused by nitrate leaching and surface runoff N losses, may contribute another 0.15-0.42 kg N ha~(-1) yr~(-1). Our study shows that nitrate leaching lowered direct N_2O emissions, highlighting the importance for a better understanding of the tradeoff between direct and indirect N_2O emissions for the development of meaningful N_2O emission strategies.