在世界上许多亚热带地区,在晚秋和冬季(1—10℃)多年生禾草停止生长时,放牧家畜缺乏足够的饲草。这些地区生长季降雨量较高,温度适中,可是由于特殊土壤状况和雨量分布不匀,往往引起土干旱或土壤积水过多,使优质牧草产量减 In many subtropical regions of the world, grazing livestock lack sufficient forages when perennial grasses cease to grow in late autumn and winter (1-10 ° C). In these growing seasons, the rainfall is relatively high and the temperature is moderate. However, due to uneven distribution of special soil conditions and rainfall, soil drought or excessive soil water often leads to a decrease in the yield of good forage grass