Nitrous oxide emissions and nitrate leaching from a rain-fed wheat-maize rotation in the Sichuan Basin, China uri icon

abstract

  • Aims A 3-year field experiment (October 2004?October 2007) was conducted to quantify N2O fluxes and determine the regulating factors from rain-fed, N fertilized wheat-maize rotation in the Sichuan Basin, China. Methods Static chamber-GC techniques were used to measure soil N2O fluxes in three treatments (three replicates per treatment): CK (no fertilizer); N150 (300 kg N fertilizer ha?1 yr?1 or 150 kg Nha?1 per crop); N250 (500 kg N fertilizer ha?1 yr?1 kg or 250 kg Nha?1 per crop). Nitrate (NO3?) leaching losses were measured at nearby sites using free-drained lysimeters. Results The annual N2O fluxes from the N fertilized treatments were in the range of 1.9 to 6.7 kg Nha?1 yr?1corresponding to an N2O emission factor ranging from 0.12%to 1.06%(mean value: 0.61%). The relationship between monthly soil N2O fluxes and NO3- leaching losses can be described by a significant exponential decaying function. Conclusions The N2O emission factor obtained in our study was somewhat lower than the current IPCC default emission factor (1 %). Nitrate leaching, through removal of topsoil NO3?, is an underrated regulating factor of soil N2O fluxes from cropland, especially in the regions where high NO3- leaching losses occur

publication date

  • 2013