旱坡地麦田夏闲期耕作措施对土壤水分有效性的影响

 麦田夏闲期末 ,免耕覆盖和深松留高茬处理的土壤蓄水量各增加 12～ 33和 9～ 2 4mm。土壤水分蒸发量(E)在 1999和 2 0 0 1年夏休闲期间分别减少 7～ 8和 34～ 36mm ,然而 ,小麦生育期的水分蒸散量 (ET) ,尤其是在2 0 0 0～ 2 0 0 1年期间较传统耕翻处理提高约 4 7mm。连续采用保持耕作措施的第 2年冬小麦产量增加 ,少耕、免耕和深松处理的产量分别较对照增加 3%、5 %和 8%。深松处理的小麦产量最高 ;免耕处理的经济效益最高。采用保持耕作措施 ,尤其免耕和深松 ,对于增加土壤蓄水、减少蒸发损失、提高水分有效性、节省能耗以及改善作物产量显示出最佳的效果。

Water Availability for Winter Wheat Affected by Summer Fallow Tillage Practices in Sloping Dryland

The effects of tillage on winter wheat were studied on the sloping farmlands in Luoyang, Henan Province in the semihumid to arid loess plateau areas of North China. Different tillage methods including reduced tillage (RT), no-till (NT), 2 crops/year (2C), subsoiling(SS), and conventional tillage (CT) were compared to determine the effects of tillage methods on soil water conservation, water availability, and wheat yields. No-till and subsoiling showed good effects on water conservation. The soil water storage increased by 12-33 mm with no-till and 9-24 mm with subsoiling at the end of summer fallow periods. The soil evaporation with NT and SS decreased by 7-8 and 34-36 mm during the fallow periods of 1999 and 2001, respectively. Water use (ET) with NT and SS increased by about 47 mm during wheat growth periods of 2000-2001. Treatment RT and 2C had low water storage and high water losses during the fallow periods. The winter wheat yields with conservation tillage practices were improved in the 2nd year, increased by 3%, 5% and 8% with RT, NT and SS, respectively, compared with CT. The highest wheat yields were obtained with subsoiling, and the maximum economic benefits from no-till. All conservation tillage practices provided great benefits in saving energy and labors, reducing operation inputs, and increasing economic returns. No-till and subsoiling have shown promise in increasing water storage, reducing water loss, enhancing water availability, and saving energy, as well as increasing wheat yield.