黄土高原不同立地条件下柠条林地土壤水分的变化规律

Changes of caragana woodland soil moisture under different sites in Loess Plateau

通过对黄土高原西部丘陵区兰州市郊10龄人工柠条林地土壤水分状况的连续定位监测,对比分析了不同生长期、不同坡向柠条林地土壤水分的垂直变化的异同,以及柠条对周围土壤含水量的影响.结果表明：在生长季内,从生长初期到生长旺季再到生长末期,整体土壤含水量变化为先减少后增加,这与植被生长耗水规律相符;各坡向土壤含水量的垂直变化具有一定的相似性,阴坡、半阴坡和半阳坡的柠条林地0～60cm土层为土壤含水量剧变层,60～180cm土层为土壤含水量相对稳定层;生长季内,不同生长时期、不同立地条件下的土壤含水量是有差异的,3个坡向平均土壤含水量从小到大为：阴坡〈半阴坡〈半阳坡,主要受地表植被及地理位置的影响;柠条对周围土壤水分的影响与土壤含水量的大小有关,土壤含水量越大柠条对周围土壤含水量影响范围越小.

According to the continuous location monitoring of soil water status of 10 age artificial caragana woodland in a hilly area of the Loess Plateau in the western suburbs of Lanzhou,this paper analyzed the similarities and differences of caragana woodland＇s soil moisture changes comparatively in different growing seasons,under different aspects.The results showed that：In the growing season,from the initial stage to the growing season then to growth stage,the water content at first decreased and then increased,which was consistent with the law of vegetation water.Vertical variation of soil moisture content of each aspect had a certain similarity,0～60cm soil layer had drastic changes in soil moisture on shady,the soil water content of 60～180cm soil layer was relatively stable.The small to large order of 3aspects＇ average soil moisture was as shady〈semi-shady〈 semi-sunny,mainly due to the impact of vegetation and geography.The impact on soil moisture around caragana was related with the size of the soil moisture,the greater water content the smaller impact on the surroundings.