条带垄覆对西南黄壤坡耕地径流和高粱水分利用的影响

Effects of strip-mulching ridges on runoff and soil water use for sorghum in southwest yellow soil slope farmland

针对西南区坡耕地季节性干旱突出、降水径流损失大、高粱低产低效益等问题。2020—2021年,在黔西南山区以前茬种植春玉米的7°黄壤缓坡耕地为研究对象,研究了横坡种植模式(作物行向与坡向垂直)下传统露地平作(CK)、条带垄覆地膜(RFM)和条带垄覆玉米整秆(RSM)3种不同处理对径流、以及高粱耗水特性、水分利用效率、产量和纯收效益的影响。结果表明,与CK相比,在横坡垄作模式下,RFM和RSM处理高粱生育期内的降雨径流深度分别平均显著下降27.3%和42.1%,纳水系数分别平均增加9.5和14.6个百分点。2个条带垄覆横坡种植较CK显著增加高粱生育期的耗水量,其中拔节至抽穗阶段、灌浆至成熟阶段耗水量与产量分别呈显著(r=0.51^(*))和极显著(r=0.81^(**))正相关。与CK相比,RFM、RSM显著增加高粱成熟期生物量、穗粒数和千粒重,籽粒产量分别平均显著增加8.5%和6.2%,但水分利用效率分别平均显著下降12.6%和21.4%。主要原因是,条带垄覆可显著增加高粱全生育期0~100 cm土壤贮水量,提高拔节至抽穗、灌浆至成熟阶段的耗水量,促进了高粱植株的生长发育和产量形成,且高粱秸秆产量的增幅(21.4%)显著高于籽粒产量增幅(7.3%),秸秆产量的大幅增加虽然降低了水分利用效率,但秸秆产量的增加是籽粒增产的重要保障。RSM处理的纯收益和产投比分别平均较CK增加2962.9元hm^(-2)和2.3%,而RFM处理由于增加了劳动强度、机械和地膜投入,导致纯收益和产投比分别平均较CK下降1502.6元hm^(-2)和32.6%。因此,条带垄覆玉米整秆横坡种植在显著提高降水有效性的同时,可实现产量和纯收益双增的目的,是西南黄壤旱坡耕地高粱增产增收的可行模式。

Aiming at the problems such as prominent seasonal drought,large loss of precipitation and runoff,low yield-benefit of sorghum in southwest sloping farmland in China.During 2020–2021,the 7°yellow soil gentle slope cultivated land of previous spring corn was taken as the research object in the southwestern mountains area of Guizhou Province.The effects of three different treatments of traditional open field plain cropping(CK),alternating plastic film strip mulching only on ridge and furrow planting(RFM),and alternating whole maize straw strip mulching only on ridge and furrow planting(RSM)on runoff,water consumption characteristics,water use efficiency,yield and net economic benefits of sorghum were studied under the Transverse Slope Planting Model(TSPM:crop row direction is perpendicular to slope direction).Compared with CK,both RFM and RSM treatments under the TSPM significantly decreased rain-runoff depth during the whole growth period by 27.3%and 42.1%on average,and the water intake coefficient increased by 9.5 and 14.6 percentage points on average,respectively.The water consumption during the growth period of sorghum was significantly increased by the two strip-mulching only on ridges and cross planting in furrows,and the water consumption during the jointing stage to heading stage and the grain-filling stage to maturity stage were significantly(r=0.51^(*))and extremely significantly(r=0.81^(**))positively correlated with the grain yield,respectively.Compared with CK,RFM and RSM significantly increased biomass,kernels per spike and 1000-grain weight at maturity,and grain yield for sorghum was significantly increased by 8.5%and 6.2%,respectively,while water use efficiency was significantly decreased by 12.6%and 21.4%,respectively.Strip-mulching ridge treatments could increase the soil water storage of 0–100 cm soil profile during the whole sorghum growth stage,increase water consumption amount from jointing to heading and from grain-filling to maturity stage.Strip-mulching also improved the growth and development of sorghum plants and the formation of grain yield.Compared with CK,the increase of sorghum straw yield(21.4%)in maturity was significantly higher than that of grain yield(7.3%).Although the increase of straw yield reduced the water use efficiency,it was an important guarantee for grain yield increase.Compared with CK,the average net economic benefit and the output/input for RSM treatment increased by 2962.9 Yuan hm^(-2) and 2.3%,respectively,while the average net economic benefit and the output/input for RFM treatment decreased by 1502.6 Yuan hm^(-2) and 32.6%,respectively,due to the obvious increase of labor intensity,mechanical and plastic film input.Therefore,RSM treatment can significantly improve effectiveness of precipitation and achieve double increase yield and net economic benefit,which is a feasible model to increase the yield-income of sorghum in yellow soil slope farmland in southwest China.