保护性耕作下棉花-春玉米轮作对玉米田土壤性状及水分利用效率的影响

Effects of Cotton-Maize Rotation on Soil Characteristics and Water Use Efficiency in Maize Field Under Conservation Tillage

为探索棉花-春玉米轮作下,棉花秸秆还田配合耕作措施对土壤性状和玉米水分利用效率的影响,通过4 a大田定位试验,以试验处理前土壤理化性质为参照,研究了翻耕秸秆还田(PT+SR)、旋耕秸秆还田(RT+SR)、翻耕秸秆不还田(PT+NSR)、旋耕秸秆不还田(RT+NSR)、免耕秸秆还田(NT+SR)、免耕秸秆不还田(NT+NSR)对土壤容重、水分、养分、微生物等的影响;不同处理方式对玉米产量、产量构成因素、水分利用效率的影响。结果表明,秸秆还田配合耕作措施可有效降低0~20 cm和20~40 cm土层土壤容重,以PT+SR处理效果最优,与处理前相比,降幅达9.87%和7%。PT+SR处理在玉米生长中后期具有较好的蓄水保墒效应,玉米产量和水分利用效率最高,2 a平均玉米籽粒产量和水分利用效率分别达到了1.29万kg/hm~2和2.42 kg/m~3。秸秆还田配合耕作措施可有效提高耕层土壤有机碳、全氮、碱解氮、有效磷和速效钾含量以及真菌、细菌和放线菌数量,其中以PT+SR处理效果最优,分别较试验处理前提高了11.9%、40.5%、32.8%、23.1%、24.6%、74.3%、72.1%和41.9%。通过多年试验证实,在棉花-春玉米轮作区,棉花秸秆还田配合翻耕,可以有效改善土壤物理特性,增加土壤养分含量和有益微生物数量,增强土壤蓄水保墒能力,进而显著提高玉米籽粒产量和水分利用效率。

In order to explore the effects of cotton straw return combined with tillage on soil properties and maize water use efficiency under cotton-spring maize rotation,a four-year field positioning experiment was conducted.Using soil physical and chemical properties before experiment as a reference,the effects of tillage straw returning (PT+SR),rotary tillage straw returning (RT+SR),tillage straw not returning(PT+NSR),rotary tillage straw not returning (RT+NSR),no-tillage straw returning (NT+SR),and no-tillage straw returning (NT+NSR) on soi bulk density,moisture content,nutrient content,microorganism were studied.The effects of different treatment on maize yield,yield components and water use efficiency were also studied.The results showed that straw returning combined with tillage measures could effectively reduce soil bulk in 0~20 cm and 20~40 cm soil layers and PT+SR had the best effect which was reduced by 9.87%and 7%compared with that before treatment.The PT+SR treatment had relatively good soil moisture conservation effect in the middle and late period of maize growth,and it also achieved the highest maize grain yield and water use efficiency.The two-year average maize grain yield and water use efficiency with PT+SR reached 1.29×10~4kg/hm~2and 2.42 kg/m~3respectively.Straw returning combined with tillage could effectively increase soil organic carbon,total nitrogen,alkali-hydrolysable nitrogen,available Phosphorus,available Potassium contents,as well as the number of fungi,bacteria and actinomycetes,among which PT+SR treatment had the best effect,which increased by 11.9%,40.5%,32.8%23.1%,24.6%,74.3%,72.1%and 41.9%,respectively.After years of experiments,it was confirmed that cotton straw returning combined with tillage could effectively improve soil physical properties,increase soil nutrient content and number of beneficial microorganisms,enhance soil water conservation ability,and significantly increase crop yield and water use efficiency in cotton-maize rotation area.