冀西北高原油菜、苜蓿混播人工草地土壤水分动态研究

Research of Soil Moisture Dynamic on the Rape-forage Mixture Pasture in the North-western Plateau of Hebei.

１９９１～１９９４年在冀西北高原二阴滩地上对油菜、苜蓿混播人工草地土壤水分动态进行了研究。结果表明，人工草地生育期土壤水分季节变化分为春季返浆蒸发失墒期（３～５月）、夏季雨水下渗水分恢复期（６～８月）和秋季水分蒸发消耗期（９～１０月）；垂直变化可分为活跃层（０～４０ｃｍ）、次活跃层（４０～８０ｃｍ）和水分相对稳定层（８０ｃｍ以下）。现蕾开花—结籽期耗水量占全生育期耗水量的５８％，是牧草需水关键期。混播草地除当年生产４６６．５ｋｇ／ｈｍ２油菜籽外，还可平均生产较自然草场增长１．２６４倍的生物量。

This paper studied the soil moisture dynamic on rape-forage mixture pasture in high land of the northwestern plateau of Hebei. The results showed that the seasonal variation of soil water of artificial grassland was divided into three periods which were the period of losing water with evaporation in Spring (from March to May), which included the instable melting stage (2 March to 8 April) and the stable melting stage (8 April to 30 April), the period of water restored with rain in Summer (from June to August), and the period of water evaporation for losing in Autumn (from Sepember to October). The vertical variation was divided into three layers, which were active layer (0～40cm)、secondary active layer (40～80cm) and relatively stable layer (under 80cm). The water consumption in blooming-seed beating period accounted for 58 percent of that in the whole period. This period was the key period of forage for water. The production dynamic of rape-forage mixture pasture showed that planting forage could increase 126.4 percent dry biomass herbage production in addition to 466.5kg/hm 2 rape seeds in the first year, and notably raise the precipitation use efficiency.