Articles
BAI Fangfang, LI Ping, LU Hongfei, LI Baiyu, QI Xuebin, MAO Wenwen
【Objective】 N2O is a greenhouse gas 298 times more effective than CO2 at trapping heat in the atmosphere. Reducing its emission from agricultural soils hence plays a crucial role in mitigating global warming. In this paper, we investigate experimentally the efficacy of regulating nitrogen fertilization to reduce N2O emission from wheat-maize rotation farmlands in Northern China.【Method】The experiment was conducted in field, consisting of conventional nitrogen fertilization of 300 kg/hm2 (N1), and reduced nitrogen fertilization of 240 kg/hm2 (N2). Without nitrogen fertilization was taken as the control (CK). In each treatment, we measured N2O efflux during the growing season of the wheat and maize, respectively, as well as soil properties.【Result】① Reducing nitrogen fertilization effectively reduced N2O efflux; N2O efflux in the maize growing season was much higher than that in the winter wheat growing season. Because of temperature difference, N2O efflux induced by nitrogen fertilization to maize was higher than that to the wheat. ② The N2O efflux was influenced by soil nitrogen and soil properties; its variation with these factors can be fitted to N2O efflux =181.952+1.450×NO3--N+8.401×NH4+-N-0.514×EC for the wheat, and N2O efflux = -354.606+4.592×NO3--N +157.848×NH4+-N to the maize, where EC is electrical conductivity of soil solution.【Conclusion】Appropriately reducing nitrogen fertilization can reduce N2O efflux in winter wheat-maize rotation production systems without compromising the crop yields in Northern China, with the reduction in the maize growing season more significant than in the wheat growing season.
