The excessive nitrogen(N) fertilizer input coupled with flood irrigation might result in higher N leaching and lower nitrogen recovery efficiency(NRE).Under an intensive rice system in the Ningxia irrigation region,China,environmental friendly N management practices are heavily needed to balance the amount of N input for optimum crop production while minimize the nitrogen loss.The objective of this study was to determine the influences of side-dressing(SD) technique in mechanical transplanting systems on the NRE,N leaching losses and rice yield in anthropogenic-alluvial soil during two rice growing seasons(2010-2011).Four fertilizer N treatments were established,including conventional urea rate(CU,300 kg ha~(-1)yr~(-1));higher SD of controlled-release N fertilizer rate(SD1,176 kg ha~(-1)yr~(-1));lower SD of controlled-release N fertilizer rate(SD2,125 kg ha~(-1)yr~(-1));and control(CK,no N fertilizer).Field lysimeters were used to quantify drainage from undisturbed soil during six rice growing stages.Meanwhile,the temporal variations of total nitrigen(TN),NO_3~--N,and NH_4~+-N concentrations in percolation water were examined.The results showed that SD1 substantially improved NRE and reduced N leaching losses while maintaining rice yields.Across two years,the averaged NRE under SD1 treatment increased by 25.5%as relative to CU,but yet the rice yield was similar between two treatments.On average,the nitrogen loss defined as TN,NH_4~+-N,and NO_3~--N underthe SD1 treatment reduced by 27.4,37.2 and 24.1%,respectively,when compared with CU during the study periods.Although the SD2 treatment could further reduce N leaching loss to some extent,this technique would sharply decline rice yield,with the magnitude of as high as 21.0%relative to CU treatment.Additionally,the average NRE under SD2 was 11.2% lower than that under SD1 treatment.Overall,the present study concluded that the SD technique is an effective strategy to reduce N leaching and increase NRE,thus potentially mitigate local environmental threat.We propose SD1 as a novel alternative fertilizer technique under an irrigated rice-based system in Ningxia irrigation region when higher yields are under consideration. The excessive nitrogen (N) fertilizer input coupled with flood irrigation might result in higher N leaching and lower nitrogen recovery efficiency (NRE) .Under an intensive rice system in the Ningxia irrigation region, China, environmental friendly N management practices are heavily needed to balance the amount of N input for optimum crop production while minimizing the nitrogen loss. The objective of this study was to determine the influences of side-dressing (SD) technique in mechanical transplanting systems on the NRE, N leaching losses and rice yield in anthropogenic- alluvial soil during two rice growing seasons (2010-2011) .Four fertilizer N treatments were established, including conventional urea rate (CU, 300 kg ha -1 yr -1); higher SD of controlled-release N (SD1, 176 kg ha -1 yr -1); lower SD of controlled-release N fertilizer rate (SD2, 125 kg ha -1 yr -1); and control (CK, no N fertilizer) .Field lysimeters were used to quantify drainage from undisturbed soil during six rice The temporal variations of total nitrigen (TN), NO_3 ~ --N, and NH_4 ~ + -N concentrations in percolation water were examined. The results showed that SD1 substantially improved NRE and reduced N leaching losses while maintaining rice yields.Across two years, the averaged NRE under SD1 treatment increased by 25.5% as relative to CU, but the rice yield was similar between two treatments. On average, the nitrogen loss defined as TN, NH 4 ~ + -N, and NO 3 ~ - N underthe SD1 treatment reduced by 27.4, 37.2 and 24.1%, respectively, when compared with CU during the study periods.Although the SD2 treatment could further reduce N leaching loss to some extent, this technique would sharply decline rice yield, with the magnitude of as high as 21.0% relative to CU treatment. Additionally, the average NRE under SD2 was 11.2% lower than that under SD1 treatment. Overall, the present study concluded that the SD technique is an effective strategy to reduce N leaching and increase NRE, thus potentially mitigate local environmental threat. We propose SD1 as a novel alternative fertilizer technique under an irrigated rice-based system in Ningxia irrigation region when higher yields are under consideration.