不同耕作方式对黑土农田土壤水分及利用效率的影响

Effects of tillage management on soil water dynamics,yield and water use efficiency in arable black soil cropping system in Northeast China

在土壤耕作长期定位试验的基础上,研究了免耕秸秆覆盖(NT)和少耕(RT)对东北黑土区农田土壤水分及利用效率、玉米产量及特性的影响。结果表明:在作物生长季3种耕作措施土壤剖面含水量整体上呈先降低后增加的变化趋势,各时期20～40 cm土层含水量均较低。免耕可显著提高0～90 cm土层土壤含水量,90 cm土层以下三种措施土壤含水量差异逐渐降低,到190 cm土层差异不明显。土体储水量主要受降雨及不同耕作措施的影响,在干旱的春季以及降水量较少的秋季土体储水量较低,表现为:免耕>传统>少耕,而在降水量较大时土体储水量相应增加,表现为:少耕>免耕>传统。3种耕作措施下玉米叶面积指数变化趋势一致,总体表现为:传统>少耕>免耕,其中传统和少耕最高分别比免耕高0.22和0.26。在生长季少耕蒸散量最高。传统耕作玉米籽粒产量和水分利用效率分别较免耕和少耕高30%和17%,29%和11%,籽粒产量均存在显著性差异(P<0.05),表现为:传统>少耕>免耕,所以对于玉米而言,在该区不适宜实施免耕秸秆覆盖和少耕这两种保护性耕作体系。

A field experiment was conducted to evaluate the effects of no-tillage （NT） and reduced tillage （RT） on soil water storage, water use efficiency （ WUE）, and their effects on corn yield in Northeast China. Soil moisture was measured from May to September in 2009, and water storage and WUE was calculated. The results showed that, com- pared to conventional tillage （ CT）, soil water content under NT was higher in 0 - 90 cm soil layer and the difference de- creased with soil depth increasing. There was no difference at the depth of 190 cm. Soil water storage was mainly influ- enced by rainfall and soil followed the order of NT 〉 tillage , thus soil water storage was lower in windy and rainless spring and autumn, and they CT 〉 RT. The soil water storage order changed to RT 〉 NT 〉 CT in rainy summer season. The furrow was loosened by zonal tillage in RT, which increased infiltration and benefited agriculture. LAI in NT was respec- tively 0.22 and 0.26 lower than those in CT and RT. The evapotranspiration （ET） in RT during the growing season was the highest. The corn grain yield and WUE in CT were 30% and 17% higher than those in NT, and 29% and 11% higher than those in RT, respectively. The corn grain yield in the three tillage systems were significantly different （ P 〈 0.05） . So NT and RT is infeasible in corn production, and CT is still undeniable soil tillage practice with higher yield and WUE in arable black soil cropping system in this region.