Manure application improved carbon sequestration, nitrogen use efficiency and reduced environmental contamination 

Abstract

<p>In order to improve carbon (C) sequestration, nitrogen (N) use efficiency (NUE), and crop yield, as well as decreased environmental contamination, efficient N fertilization is an important management strategy. We conducted a three-year field experiment (2016-2018) to evaluate the gradual replacement of mineral N by organic manure N on soil organic C (SOC) and soil total N (STN) storage, rice yield and yield components, rice C accumulation and N uptake, NUE and N balance. Manure treatments increased STN and SOC contents as compared to mineral fertilizers, simultaneously increased STN and SOC storage. Relative to the mineral fertilizer, 50% manure improved NUE and increased the effective panicle, seed setting rate, grain yield, and straw yield. In comparison with sole mineral fertilizers, 50×50% mineral and manure combination increased aboveground N uptake and aboveground C accumulation, while 100% manure reduced aboveground N uptake and aboveground C accumulation. Combined 50×50% mineral and manure fertilization decreased N surplus by 61.5% as compared with mineral fertilization, while it increased NREac by 10.7%. Considering the improvements in C sequestration and NUE, simultaneously decreased the risk of environmental contamination, combined 50×50% mineral and manure application is a promising fertilization strategy.</p>