耕作方式对太湖地区冬小麦生长季N2O排放的影响

采用静态暗箱-气相色谱法对2009年11月至2010年6月冬小麦(Triticum aestivum L.)生长季N2O排放通量进行田间原位观测,研究不同耕作方式(免耕、少耕、传统耕作)对太湖地区稻麦轮作系统麦季土壤N2O排放的影响。结果表明:有植株参与下免耕、少耕和传统耕作的冬小麦生长季N2O平均排放通量分别为63.75μg·m-2·h-1、39.94μg·m-2.h-1和48.83μg·m-2·h-1,无植株参与下分别为73.48μg·m-2·h-1、52.97μg·m-2·h-1和63.60μg·m-2·h-1,麦季N2O排放通量的季节变化与5 cm、10 cm土壤温度呈显著或极显著线性正相关(r=0.400*～0.654**,n=28)。小麦种植对N2O的排放影响较大,无植株参与的N2O季节总排放量显著高于有植株参与的处理(P<0.05);耕作方式显著影响冬小麦农田N2O季节总排放量(P<0.05),有植株参与下麦季N2O总排放量少耕较免耕和传统耕作分别减少37.3%和17.9%,无植株参与下分别减少28.0%和16.7%。研究表明太湖地区冬小麦采用少耕措施可减少麦季N2O的排放。

Effect of tillage methods on N2O emissions during winter wheat season in Taihu region

From November 2009 to June 2010,we conducted a field experiment on winter wheat(Triticum aestivum L.) to investi-gate the effect of tillage methods(no-tillage,reduced tillage and conventional tillage) on N2O emissions in Taihu region by using the method of static chamber-gas chromatographic techniques.The results demonstrated that during winter wheat season,the mean N2O fluxes with wheat crop of the no-tillage(NT),reduced tillage(RT) and conventional tillage(CT) were 67.11 μg.m-2.h-1,42.04 μg.m-2.h-1 and 51.40 μg.m-2.h-1,respectively.Without wheat crop,the mean N2O fluxes of the NT,RT and CT were 77.35 μg.m-2.h-1,55.76 μg.m-2.h-1 and 66.95 μg.m-2.h-1,respectively.Correlation analysis showed that N2O emission flux under different tillage meth-ods were positively related to soil temperature both at the depth of 5 cm and 10 cm during winter wheat season(r=0.400*～0.654**,n=28).The average total emissions of N2O without wheat crop during winter wheat season were significantly higher than that with wheat crop.Compared to NT,RT decreased total emissions of N2O by 37.3% with wheat crop and by 28.0% without wheat crop,respectively.In contrast with CT,RT decreased total emissions of N2O by 17.9% with wheat crop and by 16.7% without wheat crop,respectively.The results of this study suggest that the reduced tillage is one of the effective measures to reduce total N2O emissions during winter wheat season in Taihu region.