黄土高原沟壑区杏树林地土壤水分时空动态变化及适宜性研究

Temporal-spatial Changes of Soil Moisture and Suitability for Apricot Forest in Loess Gully Region

水分是制约黄土高原地区生态环境恢复和经济发展的主要限制因子。研究黄土高原土壤水分变化规律,有着极其重要的科学和实际意义。本研究以杏树为调查对象,通过测定不同坡向林地土壤水分,分析了土壤水分的时空动态变化规律,并根据生态位适宜度理论分析土壤水分满足杏树生长的程度。研究表明:(1)土壤含水量年内变化为不对称双峰曲线,且第二高峰峰值明显高于第一高峰峰值,阳坡与阴坡土壤水分动态有着显著的差异,阴坡土壤水分高于阳坡,阴坡蒸发量较小,降雨可以补给更深层的土壤水;(2)一年当中,土壤水分垂直分布可分为4个阶段,分别代表降雨补给土壤水、浅层土壤水入渗和再分布、浅层土壤失墒及深层土壤水上升阶段,阴坡降雨补给土壤水开始的早,阳坡土壤严重失墒开始的早。总体说来,阴坡的水生态位适宜度要好于阳坡,但不论阳坡还是阴坡,水生态位的适宜度均较低。

Water is a crucial limiting factor for the eco-environmental restoration and economic development in the Loess Plateau.That has practical and scientific significance to study the dynamic law of soil moisture.Based on measuring soil water content of apricot forests in the loess gully region,the temporal-spatial changes of soil moisture was studied,and the meet degree of soil moisture to apricot growth was analyzed with the help of moisture niche-fitness model.The results showed that：（1） the temporal variation of soil moisture presented a double-peak curve,the second peak value was higher than the first one,and the soil moisture of shady slope was significantly higher than that of sunny slope because of the high evaporation of sunny slope;（2） the spatial vertical distribution of soil moisture could divided into 4 types in one year,and the vertical variation of soil moisture included 4 stages： precipitation recharge stage,shallow soil moisture infiltration and redistribution stage,shallow soil moisture loss stage and deep soil moisture rise stage.Precipitation recharge of shady slope was earlier than sunny slope of which soil moisture lose early.Soil moisture niche-fitness of shady slope was better than sunny slope,but that of both slopes was low.