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通过设置四个不同的氮肥管理措施,即氮肥施用量300kgN/ha(N300)和250kgN/ha(N250)、改进的施肥模式(Optimized)以及施用缓释肥(SRU),研究华北平原夏玉米生长季土壤与大气之间CH4和N2O的交换通量及相应措施的减排潜力.结果表明,在2008年整个夏玉米生长季,土壤都是大气CH4的净吸收库和N2O的排放源.夏玉米生长季土壤氧化吸收的CH4总量从大到小依次为Optimized>N250>SRU>N300,对应的吸收总量依次为624.16、590.07、487.89以及316.02gCH4-C/ha,各处理间氧化吸收的CH4总量无显著差异.与N300和N250这两个处理相比,依据夏玉米对氮肥的需肥规律以及玉米根层土壤速效氮的供给能力而确定氮肥施用量,同时再平衡施用磷肥和钾肥的改进施肥模式能够显著降低夏玉米生长季N2O的排放.施用聚乙烯包膜的尿素也能够显著降低夏玉米季N2O的排放.夏玉米生长季土壤排放的N2O总量从大到小依次为N300>N250>Optimized>SRU,对应的排放总量依次为3462.18、2340.07、1680.00以及911.91gN2O-N/ha,相应的N2O排放系数分别为1.15%、0.94%、0.91%以及0.30%.
The growth of summer maize in North China Plain was studied by setting four different nitrogen management measures, namely nitrogen application rates of 300kgN / ha (N300) and 250kgN / ha (N250), improved optimized mode of application and slow release fertilizer (SRU) The exchange fluxes of CH4 and N2O between the soil and the atmosphere and the mitigation potential of the corresponding measures.The results showed that the soil was the net absorption of atmospheric CH4 and the source of N2O throughout the summer maize growing season in 2008. Summer maize The total amount of CH4 absorbed by the soil during the growing season was Optimized> N250> SRU> N300, and the corresponding total absorption was 624.16, 590.07, 487.89 and 316.02gCH4-C / ha, respectively. Compared with N300 and N250 treatments, nitrogen fertilizer application rate was determined according to the requirement of summer maize for nitrogen fertilizer and the availability of available nitrogen in maize root so as to rebalance the application of phosphate fertilizer and potassium fertilizer The improvement of fertilization mode could significantly reduce the N2O emission during the growing season of summer maize.The application of polyethylene coated urea could also significantly reduce the N2O emission in the summer maize season.During the summer maize growth season, N250> Op timized> SRU. The corresponding emissions totaled 3462.18, 2340.07, 1680.00 and 911.91gN2O-N / ha, respectively. The corresponding N2O emission factors were 1.15%, 0.94%, 0.91% and 0.30%, respectively.