长期不同施肥与秸秆管理对紫色土水稻田CH_4排放的影响

Effects of Different Long-Term Fertilization and Crop Residue Management on Methane Emissions from Paddy Fields with Purple Soil

为了解长期不同施肥与秸秆管理对稻田甲烷排放的影响,采用静态箱法于2011年稻季对国家紫色土肥力与肥效基地5块试验田的甲烷排放通量进行了测定.这些试验田自1991年起接受不同的处理,包括秸秆不还田且不施肥(R-)、秸秆不还田但施用PK肥(PKR-)、秸秆不还田但施用NPK肥(FnR-)、秸秆还田但不施肥(R+)、秸秆还田且施用NPK肥(FnR+).不同施肥处理田块的CH4排放季节变化模式相似,但排放量有差异.R-处理CH4的累积排放量为C 108kg/hm2,略低于PKR-的排放量.与R-和PKR-相比,FnR-的排放量则降低了31%～44%,表明在秸秆不还田的条件下,施用氮肥能够抑制稻田CH4的排放.相反,R+与FnR+的CH4排放量无显著差异,但比R-高92%～99%,比FnR-高176%～186%,说明秸秆还田能促进CH4的排放,并缓解氮肥对CH4排放的抑制作用.

To investigate the response of methane emissions to different long-term fertilization and crop residue management,a closed chamber technique has been used to measure methane fluxes from five experimental plots at the National Monitoring Base for Purple Soil Fertility and Fertilizer Efficiency during the rice-growing season in 2011.These plots have been subjected to different treatments since 1991,including no crop residue incorporation combined with no fertilization（R-）,application of P and K fertilizers（PKR-）,or application of N,P and K fertilizers（FnR-）,and crop residue incorporation combined with no fertilization（R＋） or application of N,P and K fertilizers（FnR＋）.The seasonal patterns of methane fluxes from different plots are similar but the emission rates are distinctly different between these plots.The cumulative emission of methane from the treatment R-is C 108 kg/hm2,which is a little lower than that from PKR-.The methane emission from FnR-is decreased by 31% to 44% when compared to R-and PKR-,indicating that the application of N fertilizer could inhibit methane emissions from purple paddy soils under the condition of no crop residue incorporation.In contrast,the methane emissions from R＋ and FnR＋ are not significantly different,but are 92% to 99% higher than that from R-and 176% to 186% higher than that from FnR-,suggesting that crop residue incorporation could stimulate methane emission and mitigate the inhibitory effect of N fertilization.