秸秆带状覆盖对旱地冬小麦旗叶水势及产量的影响

Effect of Straw Strip Mulching on Flag Leaf Water Potential and Yield of Winter Wheat in Dryland

为探究黄土高原西部旱农区秸秆带状覆盖对冬小麦生产的效应,以地膜覆盖(PM)和露地(CK)为对照,设4种秸秆带状覆盖SM3(覆盖度59%)、SM4(覆盖度50%)、SM5(覆盖度42%)和SM6(覆盖度37%),分析了不同处理对小麦花后旗叶水势、旗叶相对含水量、土壤含水量、产量及水分利用效率(WUE)的影响。结果表明,秸秆带状覆盖下冬小麦花后旗叶水势、旗叶相对含水量、旗叶含水量和0~40 cm土壤含水量较CK分别提高9.2%、6.6%、3.6%和30.0%;地膜覆盖下0~40 cm土壤含水量较CK提高15.1%,旗叶水势6.0%、旗叶相对含水量和旗叶含水量则分别降低6.0%、3.2%和4.1%。冬小麦花后7~28 d,旗叶水势日变化总体呈早、晚高、午间低的V型趋势;秸秆带状覆盖早、中、晚旗叶水势较CK分别提高10.6%、9.8%和7.7%,地膜覆盖分别降低4.6%、7.9%和4.8%,差异均显著。秸秆带状覆盖下冬小麦籽粒产量较CK增加3.0%~6.5%,WUE提高6.4%~17.5%,且差异达到显著水平。秸秆带状覆盖处理中,SM5具有最高的产量(3866.6 kg·hm^(-2))和WUE(15.7 kg·hm^(-2)·mm^(-1))。产量与穗数(r=0.693**)、WUE(r=0.615**)均呈极显著正相关,穗数与WUE(r=0.690**)和0~40 cm土壤含水量(r=0.570*)分别呈极显著和显著正相关。综上所述,在干旱年份土壤含水量低时,通过覆盖可增加土壤表层含水量,改善冬小麦旗叶供水情况,进而增加穗数和WUE;覆盖度为42%的秸秆带状覆盖在干旱年份增产效果最优,是适宜于西北旱作农业绿色可持续发展的种植方式。

In this study,a total of six treatment groups were designed to investigate the effects of straw strip mulching on flag leaf water potential,flag leaf relative water content,soil water content,yield,and water use efficiency(WUE)of winter wheat after flowering in dryland farming area of western Loess Plateau,including straw strip mulching treatments SM3(straw mulching coverage 59%),SM4(straw mulching coverage 50%),SM5(straw mulching coverage 42%),SM6(straw mulching coverage 37%),with plastic film mulching(PM)and open field(CK)as controls.The results showed that compared with CK,the straw strip mulching improved the flag leaf water potential,flag leaf relative water content,flag leaf water content and surface layer soil water content by 9.2%,6.6%,3.6%and 30.0%,respectively;while plastic film mulching decreased the flag leaf water potential,flag leaf relative water content,flag leaf water content by 6.0%,4.2%and 3.2%,respectively,but increased surface soil moisture by 15.1%.The diurnal variation of flag leaf water potential of winter wheat showed a V-shaped trend of higher in the morning and afternoon but lower at noon during 7-28 days after flowering.Flag leaf water potential under straw strip mulching treatments in the morning,noon and afternoon was increased by 10.6%,9.8%and 7.7%compared with that under CK,while that under plastic film mulching was reduced by 4.6%,7.9%and 4.8%,respectively.Compared with CK,the yield and WUE of winter wheat under SM was increased by 3.0%-6.5%and 6.4%-17.5%,and there are significant difference between SM and CK.SM5 treatment had the highest yield(3866.6 kg·hm^(-2))and WUE(15.7 kg·hm^(-2)·mm^(-1))among all straw strip mulching treatments.Grain yield has positive correlation with the spike number per unit area(r=0.693**)and WUE(r=0.615**);the spike number per unit area has a positive correlation with WUE(r=0.690**)and surface soil water content(r=0.570*).Overall,increasing surface water content improved the water supply of flag leaf of winter wheat by mulching in arid years,and thus enhanced spike number per unit area and WUE.Straw strip mulching with 42%coverage has the best yield increase effect in dry years,which is suitable for the green and sustainable development of dry farming in Northwest of China.