库布齐东段典型人工固沙林土壤水分时空变化特征

以库布齐沙漠东段典型人工固沙林（油蒿林、沙柳林、柠条林）为对象，利用TRIME-PICO土壤水分观测系统对2017-2019年生长季迎风坡顶部、中部和底部0～180 cm土层深度土壤含水量进行连续监测，探讨区域植被类型和环境因子对土壤水分时空变化的影响。结果表明，研究区平均土壤含水量年际变化受降雨量影响表现为:2019年（9.7%）>2018年（8.6%）>2017年（4.3%）；因植被生长特性差异，土壤含水量表现为:油蒿林（7.9%）>沙柳林（7.8%）>柠条林（6.9%）；不同坡位土壤含水量略有差异，油蒿林和柠条林表现为:迎风坡底部>中部>顶部，而沙柳林为:迎风坡底部>顶部>中部；不同样地土壤含水量垂直变化明显，均呈现先减小后缓慢增大的趋势，含水量最大值均出现在浅层（0~40 cm），由于降雨入渗和植被根系分布的不同，最小值在中层和深层均有出现；3种样地土壤水分时间变异系数为0.2~0.4，浅层时间变异性较大，深层较为稳定；土壤水分与垂直变异系数呈负相关。总体上，季节变化和土层深度在时间和空间维度对土壤水分有较大影响，土壤水分和植被生长既相互作用又相互制约。

Spatial and Temporal Characteristics of Soil Moisture in Typical Sand Fixation Plantations in the Eastern Hobq

Soil moisture is a key factor for vegetation restoration in desert area.In this study,we took the typical man-made sand fixation forests(Artemisia ordosica,Salix psammophila,and Caragana korshinskii)in the eastern margin of Hobq desert as the research objects,to conduct a continuous monitoring of the soil moisture in 0-180 cm layer at the top,middle and bottom of windward slope in the growth season of 2017-2019 by using Trime-pico Soil Moisture Observation System.The objective of this study was to examine the effects of vegetation types and environmental factors on the spatial-temporal dynamics of soil moisture in desert.The results showed that the interannual variation of the average soil moisture content in the study area was affected by rainfall,which is was shown as:2019(9.7%)>2018(8.6%)>2017(4.3%).Because of the difference in vegetation growth characteristics,the soil moisture contents of the three sand fixation forests were in the order of A.ordosica(7.9%)>S.psammophila(7.8%)>C.korshinskii forest(6.9%).The soil water content of different slope positions is was slightly different.For A.ordosica forest and C.korshinskii forests,it was in the order of are at the bottom>middle>top of the windward slope,while for S.psammophila forest,the order was is at the bottom>top>middle of the windward slope;The vertical change of soil moisture in different areas was obvious,which presented the trend of first decreasing and then slowly increasing with the depth of soil layer.The maximum value of water content appeared in the shallow layer(0-40 cm),and the minimum value appeared in the middle and deep soil layer due to different rainfall infiltration and distribution of vegetation root system.The variation coefficient of soil water in the three soils forests ranged from 0.2 to 0.4,the variation in shallow soil water was large,but it was relatively stable in deep soil.There was a negative correlation between soil moisture and vertical coefficient of variation.In general,seasonal change and soil depth had great influence on soil moisture in time and space dimensions,soil moisture and vegetation growth interacted and restricted each other.