越冬作物覆盖保水效应及对后茬大豆水分利用效率和产量的影响

Water conservation effect of overwintering crops mulching and its effect on water use efficiency and yield of subsequent soybean

为探索越冬作物冬油菜(Brassica rape)、冬小麦(Triticum aestivum)、冬豌豆(Pisum sativum)的覆盖保水效应及对后茬大豆的影响,于2019—2020年和2020—2021年生长季,在甘肃省镇原县以地膜覆盖和露地为对照,比较了5种处理的地表覆盖度、耗水特征及后茬大豆水分利用效率和产量的差异,分析了越冬作物耗水量与生物量和地表覆盖度的相关性。结果表明:从出苗期到刈割期,冬小麦生物量分别较冬油菜和冬豌豆显著增加15.6%和130.5%(P<0.05),冬油菜和冬小麦具有更高的地表覆盖度,分别为89.2%和84.4%。冬油菜、冬小麦、冬豌豆的耗水量分别较地膜覆盖和露地增加50.4%和18.6%、150.2%和97.4%、41.6%和11.7%;冬油菜和冬小麦耗水量与生物量的相关系数分别为0.923和0.966,呈显著正相关(P<0.01),与地表覆盖度相关性不显著,冬油菜耗水量与地表覆盖度间有负相关趋势。在相对干旱生长季,冬油菜和冬豌豆耗水量分别较露地减少6.7 mm和7.5 mm,具有保水效应,冬小麦和冬豌豆后茬种植大豆具有更高的籽粒产量,产量水平分别为2583.3 kg·hm^(-2)和2550.4 kg·hm^(-2),冬小麦后茬大豆的水分利用效率最高,2 a的平均值为8.3 kg·hm^(-2)·mm。综合分析地表覆盖度、耗水量、土层水分变化、大豆籽粒产量等因素,在本试验条件下,冬油菜、冬豌豆是西北旱作区冬季农田覆盖和土壤水分保持的有效措施,冬小麦是大豆种植的优势茬口。

The purpose of this study was to explore the effects of overwintering crops mulching on soil water conservation and water use efficiency and yield of subsequent soybean.The experiment was conducted in 2019-2020 and 2020-2021.The diversity of land coverage,biomass,water consumption and soybean yield underwinter rape(Brassica pape),winter wheat(Triticum aestivum),winter pea(Pisum sativum),plastic film mulching,and open field were compared.The results showed that the biomass of winter wheat increased by 15.6%and 130.5%compared with winter rape and winter pea from seedling to cutting.The land coverage of winter rape and winter wheat were 89.2%and 84.4%respectively,which were significantly(P<0.05)higher than other treatments.The water consumption of winter rape,winter wheat and winter pea in 0~100 cm soil layer increased by 50.4%and 18.6%,150.2%and 97.4%,41.6%and 11.7%compared with plastic film mulching and open field,respectively.The correlation coefficients between water consumption and biomass of winter rape and winter wheat were 0.923 and 0.966,showing a significant positive correlation(P<0.01),which had no significant correlation with land surface coverage,but the correlation between water consumption of winter rape and surface coverage was negative.During the dry growing season,winter rape and winter pea reduced water consumption by 6.7 mm and 7.5 mm compared with open field,respectively.Winter wheat and winter pea had higher grain yield of soybean,which reached 2583.3 kg·hm^(-2)and 2550.4 kg·hm^(-2),respectively,and soybean after winter wheat had the highest WUE by 8.3 kg·hm^(-2)·mm.Based on the experiment,winter rape and winter pea were effective measure for soil water conservation and sustainable development of agriculture in northwest China,and winter wheat was a suitable planting stubble for soybean planting in arid area.