延安丘陵沟壑区果园土壤储水量动态研究

Study on soil water storage dynamic in slope-orchard of Yan'an gully region

果园土壤储水量是果园高产的限制因素之一。为了提高土壤水分利用效率,实现果园高产稳产,从2001-2005年连续4年对延安飞马河流域果园土壤水分进行了监测,采用时间序列小趋势分析法研究了果园土壤储水量的动态变化规律。结果表明,果园土壤储水量趋势项在2002-2005年分别为304.9,301.2,346.3和275.7 mm,受降水量影响呈周期性波动变化,具有一定滞后性;土壤储水量变化季节项变化周期为12个月,年变化表现为1-5月呈现持续降低趋势,6-8月受降水量补给的影响呈现一定的波动,9-12月土壤储水量逐渐升高;根据各层土壤储水量的变化幅度,0-40 cm为速变层,40-100 cm为活跃层,100-200 cm为缓变层,200-300 cm为相对稳定层,300cm以下为稳定层。果园土壤储水量实测值与模拟值吻合较好,说明采用时间序列可较好地对土壤储水量进行模拟,在土壤剖面上表现为,连续干旱导致表层土壤储水量降低较大,深层土壤储水量也呈现降低趋势。

The soil water storage is one of the high-output restrictions in slope orchard.Dynamic change of soil water storage in slope orchard is studied by the method of timeliest trend.In order to enhance the soil moisture use efficiency and achieve high-stable yield,the soil moisture has been monitored for four years in slope orchard in Yan＇an Feimahe catchments from 2001-2005.The result shows that trends items of soil storage are 304.9,301.2,346.3 and 275.7 mm,respectively in 2002-2005.It takes on the cyclical variation with some lag being affected by the precipitation.The cycle of seasonal items of soil storage is 12 months.The soil storage continues declining from January to May,fluctuating from June to August and rising gradually from September to December.The soil layer can be divided into five.0-40 cm is variable-speed layer,40-100 cm is active-layer,100-200 cm is slowl-layer,200-300 cm is relatively stable-layer,and under 300 cm is stable layer according to the magnitude of changes.The measured and simulated data are in good agreement,which manifests that timeliest can simulate the soil water storage well.The surface soil storage shows a larger reduction because of continuous drought and the same as the deep soil.