Changes of water consumption regularity of native tree species in Loess Plateau under different soil water contents

Chinese. 以黄土高原大叶细裂槭、虎榛子、白刺花、辽东栎4个常见乡土树种幼苗为试验材料，用盆栽方法模拟土壤干旱条件，研究各树种在不同土壤水分条件下的耗水规律。结果表明,不同土壤水分处理下,各树种的耗水量依次是适宜水分＞中度干旱＞重度干旱；耗水量在各月的分配规律为:4,5,10月耗水少，6~9月耗水多。因土壤水分条件不同,4个树种在生长季的耗水规律也有差异,随土壤水分含量的减少，不同树种的最大耗水时期、最高耗水日及日耗水高峰有提前的趋势，总耗水量在各月份的分配比例各不相同,不同树种的耗水规律具有其自身的特点。大叶细裂槭对水分的反应较敏感，适应性强;白刺花属高耗水高水分利用效率的树种，耗水量在4个树种中最高，耗水高峰集中在7～9月，与黄土区的雨季同步，辽东栎的耗水高峰也有这一特点;耗水量最少的树种是虎榛子，其耗水系数最大，对水分的利用效率最低。

English. Using four native tree species of Acer stenolobum Rehd.var.megalophyllum,Ostryopsis davidiana，Sophora viciifolin，Quercus liaotungensis in Loess Plateau as experiment materials and Pot culture experiments simulating different soil water status, this paper mainly deals with water consumption regularity of four native tree species under different soil water contents. The results show that different soil water content have obvious effect on water consumption of four tree species, the trend is normal water＞media drought＞severe drought. The water consumption is lower in April, May, October and higher from June to September, every tree species has obvious different characteristics. Water consumption regulaity of four tree species on growth season changes with different soil water content. Time and date of the highest water consumption of different tree species have notable differences and arrive early with soil water content decreasing, Allocation ratios of total water consumption have obvious differences every month. Acer stenolobum Rehd.var.megalophyllum is sensible to soil water deficit, but it has fine ecological adaptability and higher survival rate. Sophora viciifolin has higher water consumption and high WUE characteristic and the highest water consumption among four tree species, its highest water consumption concentrating on June, July and August and in harmony with Loess Plateau rain seasons. Ostryopsis davidiana has the highest water coefficient and the lowest water consumption and low WUE characteristics.