Spring maize is one of the most popular crops planted in northeastern China. The cropping systems involving spring maize have been maintaining high production through intensive management practices. However, the high rates of nitrogen(N) fertilizers application could have introduced a great amount of nitrous oxide(N2O) into the atmosphere. It is crucial for sustaining the maize production systems to reduce N2O emissions meanwhile maintaining the optimum yields by adopting alternative farming management practices. The goal of this study was to evaluate effects of alternative fertilization and crop residue management practices on N2O emission as well as crop yield for a typical maize field in northeastern China. Field experiments were conducted during the 2010-2011 maize growing seasons(from early May to late September) in Liaoning Province, northeastern China. N2O fluxes were measured at the field plots with six different treatments including no N fertilizer use(CK), farmers' conventional N fertilizer application rate(FP), reduced N fertilizer rate(OPT), reduced N fertilizer rate combined with crop straw amendment(OPTS), slow-release N fertilizer(CRF), and reduced N fertilizer rate combined with nitrification inhibitor(OPT+DCD). The static chamber method combined with gas chromatography technique was employed to conduct the measurements of N2O fluxes. The field data showed that N2O emissions varied across the treatments. During the maize growing season in 2010, the total N2O emissions under the treatments of CK, FP, OPT, OPTS, and CRF were 0.63, 1.11, 1.03, 1.26, and 0.98 kg N ha-1, respectively. The seasonal cumulative N2O emissions were 0.54, 1.07, 0.96, 1.12, and 0.84 kg N ha-1, respectively, under CK, FP, OPT, OPTS, and OPT+DCD in 2011. In comparison with FP, CRF or OPT+DCD reduced the N2O emissions by 12 or 21%, respectively, while the crop yields remained unchanged. The results indicate that the reduction of N-fertilizer application rate in combination with the slow-release fertilizer type or nitrification i
【目的】针对环渤海区域冬小麦/夏玉米轮作系统氮肥施用量过大,环境效应逐渐增大的实际情况,研究不同氮肥施用量下长期和区域环境效应,明确冬小麦/夏玉米的减氮潜力和区域。【方法】利用定位试验和生物地球化学模型相结合的研究方法。【结果】冬小麦/夏玉米不同氮素施用量15年的模拟结果表明,随着氮肥施用量的增加,作物产量逐渐增加,到两季作物施氮量达到240—300 kg N.hm-2以上时,作物产量增加能力有限,而氮淋溶损失量则逐渐加大,土壤中残留的无机氮素也逐渐增加。与当前区域氮肥施用量364×104t相比,区域氮肥总量减少30%和优化施肥两种调控方案下环渤海地区总氮素平衡的各个输出项都有不同程度的降低,其中降低幅度最大的是氮淋溶,分别减少了67.23%和79.93%,极大地降低了氮素的环境风险。【结论】环渤海地区冬小麦/夏玉米轮作系统氮素的环境效应有随氮素施用量逐渐增加的态势,目前该种植模式具有减氮的潜力,区域减氮30%能够有效的减少环境效应,节氮潜力最明显的地区在山东东部、西南部和河北中部。
