It is vital to explore dynamic of soil moisture in artificial grass land .Clarifying the impacts of forage grass planting on soil moisture changing may provide efficient ways for the water management of rain fed grass land .Based on long term experiment ,impacts of forage grass planted on soil moisture dynamic were analyzed .The results showed follow-ing .(1) Average available soil moisture in artificial grass land of ryegrass ,chicory and alfalfa in depth of 0～100 cm soil was 88 .8 ,189 .3 mm and 181 .7 mm respectively .Monthly mean available soil moisture was relative lower from Jan-uary to April and that was relative higher from June to September ,and that gradually decreased from September to De-cember .(2) Soil weight moisture increased from the first quarter to the third quarter in the same year and that decreased from the third quarter in the last year to the first quarter in the next year .The depleted soil moisture in deep soil by arti-ficial grass in the quarter was recovered in the third quarter .(3 ) Rate of rainfall storage was the lowest (71％ ,64％ and 68％ ) from June to August and was the highest (93％ 、94％ and 94％ ) from November to March next year in artificial grass land of ryegrass ,chicory and alfalfa respectively .Soil moisture consumption rate was the highest (66％ ,70％ and 72％ ) from August to October and was the lowest (41％ ,42％ and 44％ ) from November to March next year in above mentioned artificial grass land .(4) Chicory and alfalfa were better in fresh yield ,alfalfa and chicory were better in hay yield ,alfalfa and ryegrass were better in crud protein production ,and alfalfa and chicory were better in digestible energy in the process of forage grass using at Mianyang .Soil moisture in the depth 0～100 cm could be recovered well during the third quarter and no permant dry soil layer occurred in artificial ryegrass ,chicory and alfalfa land at hilly region ,Mi-anyang ,Sichuan .Reasonable irrigation would be benefit to improve forage yield from November to April next year and ir-rigation after grass harvest could promote sprout of grass especially .%研究丘陵旱区人工草地土壤水分变化规律,能够明确饲草种植对坡耕地土壤水分的影响,对指导人工草地水分管理具有重要的现实意义.本研究采用长期定位试验的方法,分析了四川丘陵旱区不同人工草地土壤有效含水量、土壤水分剖面分布和水分利用效率等,明确了饲草种植对丘陵坡耕地土壤水分的影响,为该地区人工草地水分管理提供了理论依据.研究结果表明,(1)四川丘陵旱区人工黑麦草地、菊苣地和苜蓿地0～100 cm土层月均土壤有效含水量分别为88.8、189.3 mm和181.7 mm,其中,1-4月土壤有效含水量较低,6-9月土壤有效含水量较高,9-12月土壤有效含水量逐渐下降;(2)从第一季度(1-3月)到第三季度(7-9月)土壤重量含水率呈增加趋势,从第三季度到翌年第一季度土壤重量含水率呈降低趋势;人工草地在第一季度消耗的深层土壤水分在第三季度能得到较好恢复;(3)人工黑麦草地、菊苣地和苜蓿地的土壤蓄水率均在6-8月最小(71％ 、64％ 和68％),11月到翌年3月最大(93％ 、94％ 和94％);土壤耗水率在8-10月最大(66％ 、70％ 和72％),在11月至翌年3月最小(41％ 、42％ 和44％);(4)在绵阳丘陵坡耕地,从鲜草产量角度考虑,菊苣和苜蓿较为理想;从干草产量角度考虑,苜蓿和菊苣较为理想;从粗蛋白供应度考虑,苜蓿和黑麦草较为理想;从消化能产量角度考虑,苜蓿和菊苣较为理想.四川丘陵区黑麦草、菊苣和苜蓿的种植不会引起深层土壤干燥化现象,0～100 cm土层土壤水分在第三季度可以得到较好的恢复;从提高饲草产量角度考虑,可以根据饲草生长需要在11月至翌年4月对人工草地进行适当灌溉,尤其是在刈割后,适当灌溉有利于饲草的快速萌发.
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