耕作措施对绿洲灌区冬小麦田蒸散特征的影响

针对甘肃河西地区日渐严重的风蚀、水资源紧缺和蒸散量大等问题,于2005～2006年通过大田定位试验研究了不同耕作措施冬小麦田蒸发蒸腾特性及其影响因子。结果表明,免耕秸杆覆盖（NTS）及免耕立茬（NTSS）能显著降低土壤水分蒸发量（E）、提高水分利用效率（WUE）,且NTS优于NTSS。当裸露土壤水分过度蒸发耗损使0～10cm含水量低于13%时,覆盖处理（NTS、NTSS）的蒸发量（E）高于无覆盖处理（T、TIS及NT）,叶面蒸腾量也相对较高。TIS、NT一天中蒸发量始终高于覆盖处理,而T的蒸发主要集中在上午。蒸腾速率（T_r）与叶温（T_l）、气孔导度（G_s）和气温（T_a）呈极显著正相关,与相对湿度（RH）呈极显著负相关;E与地温（ST）呈极显著正相关而与RH呈极显著负相关。

Effects of Tillage Practices on Winter Wheat Field Evapotranspiration Characteristics at Oasis Area

As oasis area in Hexi corridor has more and more serious problems of wind erosion,shortage of water and heavy evapotranspiration,evapotranspiration characteristics of different tillage methods of winter wheat field and their influence factors were studied in 2005-2006. Results showed that:no-tillage with stubble retention(NTS)and no-tillage with stubble standing (NTSS) could reduce markedly soil evaporation and improve water use efficiency(WUE),and NTS was even better than NTSS.However,evaporation and transpiration under treatments with stubble cover(NTS and NTSS) was even higher than non-covered treatments(T,TIS and NT) when soil water content at layer of 0-10cm of non-covered treatments was lower than 13%.Normally,evaporation under treatments of TIS and NT was higher than covered treatments,and evaporation under T was strong in morning.Transpiration rate was,in a most significant state,positively,related with Tl,Gs and Ta and negatively related with RH.Evaporation was,in a most significant state,positively related with ST and negatively related with RH.