起垄覆膜集水技术对苜蓿土壤水分状况的影响

结合宁南山区退耕还林还草工程中的旱地牧草种植结构,针对紫花苜蓿生产中存在的管理粗放,土壤水分周期性严重亏缺而导致鲜草生产力低下等问题,通过布设多种集水带型比,系统测定了不同田间起垄覆膜集水技术在不同降水条件下对苜蓿土壤水分状况的影响。结果表明,集水种植能有效的调控农田水分分配机制,增加苜蓿生长期的水分供应量,使草田垄沟产流效率达到60%~84%,田间蓄墒率提高13.0%~18.9%,水分供应满足率提高11.30%~21.60%,同时该技术降低了苜蓿受干旱胁迫时的土壤水分亏缺度,采用集水种植土壤水分亏缺系数为0.1656~0.2892,而露地种植(CK)土壤水分亏缺系数为0.5364,有效的改善了土壤水分生态环境。

The Characteristics of Soil Amelioration by Water Harvesting by Ridge Building of Medicago sativa and Its Effect on Regional Water Budget

Account for issues of rude management of Medicago sativa,and the lower productivity of fresh pasture by periodic deficit of soil moisture,we combined with planting configuration of dryland pasture about project of grassland restoration from cropland in southern Ningxia mountain region, converted the extensive plant patterns to rainwater catchment and furrow planting technique by applying the theory of farmland runoff,and disposed the type of different ratio of ridge and ditch in semiarid prone to drought area,the soil water charact eristics of runoff generation and rainwater storage of different ratio of ridge and ditch under different rainfall conditions were studied.The results indicated that rainwater catchment and plant ing technique regulated the mechanism of cropland water allocation,and improved the amount of water supply on growth period of Medicago sativa,runoff generation efficiency of grassland reached 60%~84%,rainwater storage efficiency of grassland improved 13.0%~18.9%,water supply satisfied degree improved 11.30%~21.60%.Rainwater catchment and planting technique decreased soil water deficit of Medicago sativa by drought stress,soil water deficit coefficient of the technique was 0.1656~0.2892,but soil water deficit coefficient of control was 0.5364,water deficit coefficient decreased 80% and more.The technique meliorated soil water ecoenviroment,and achieved the effects of high yielding and efficiency.