少免耕与秸秆还田对极端土壤水分及冬小麦产量的影响

为了高效利用天然降雨,缓和农业水资源短缺,该试验在小麦、玉米一年两熟条件下,设置耕作措施和秸秆2个因素,其中耕作措施分为常规耕作、深松耕、耙耕、旋耕、免耕5种,秸秆因素分为玉米秸秆全量还田与不还田,共10个处理,研究了耕作措施与秸秆因素对极端土壤水分和冬小麦产量的效应。结果表明,无论秸秆还田与否,相对于常规耕作,深松耕能提高土壤水分充足期的土壤含水率,增加冬小麦产量,尤其是深松耕秸秆还田,比常规耕作无秸秆还田分别高25.74%和11.45%。秸秆因素在土壤水分充足时影响土壤含水率方面占主导地位,秸秆因素与耕作措施在土壤水分亏缺时影响土壤含水率和冬小麦产量方面均起着重要的作用。免耕、深松耕、耙耕与秸秆还田的交互效应能够增加集雨,提高冬小麦产量。研究结果还表明,冬小麦产量与土壤水分亏缺时土壤含水率相关不显著,而与土壤水分充足期土壤含水率相关显著。

Evaporation from Bare Soil in Extremely Arid Environment in Southern Israel

Microlysimeters of different sizes(5 cm 10 cm and 15 cm in length)were used extensively in the present study for the measurements of soil evapondion in site in an extremely arid area in southern Israel.All of the data obtained from the microlysimeters were used to evaluate two conventional eVaporation models developed by Black et al.and Ritchie,respectively.Our results indicated that the models could overestimate total cumulative evaporation by about 30% in the extremely arid environment.Reducing the power factor of the conventional model by a faCtor of 0.1 produced good agreement between the measured and simulated cumulative evaporation.Microlysimeter method proved to be a simple and accurate approach for the evaluation of soil evaporstion.