西宁黄土丘陵区初雨后土壤水分地理变异与植被分异规律

2016年冬春季节在青海西宁北山公园布置了典型黄土丘陵样地,连续测试了样地的土壤温度和含水率等数据。结果显示:植物根区土壤含水率在1—2月份与土壤温度紧密相关,土壤含水率由大到小的顺序为阳坡西南坡、阳坡正南坡、阳坡台地、阴坡。当土壤升温到0℃以上时,阴坡和阳坡台地涵养降水能力增强,土壤含水率急剧上升。4月份是植被尤其是乔木树种萌发需水的重要时期,15%是衡量春季植被(乔木)萌发的重要指标和依据,该时期不同地理单元土壤含水量差异显著。阴坡是该区域植被恢复的最佳地理单元,可实现植被的自然恢复;阳坡平坡加以适当的人为干预(平整、环形围闭、灌水)后,植被恢复能力与阴坡陡坡较为接近;阳坡陡坡不适宜人工恢复,应以自然恢复模式为主。

Geographical Variation and Vegetation Differentiation of Soil Moisture after Early Rain in Loess Hilly Region of Xining,Qinghai Province

We continuously measured the soil temperature and water content of sample plots located in loess hilly region of Beisban Park in Xining,Qinghai Province during the period from the winter to the spring in 2016.The soil water contents in plant roots were significantly affected by the soil temperature from January to February and the effect descending order was South-West Sunny Slope,South Sunny Slope,Sunny Tableland,and Shady Slope.After soil temperature reached to 0 ℃,soil water content of Shady Slope and Sunny Tableland increased rapidly.April was the virtual period for arbor to germinate for which 15％ is an important indicator for soil water contents.In the period,however,the differentiations of the soil water contents of different geographical units were remarkable.The shady slopes were the optimal geographical unit to naturally recover vegetation in the region.For the sunny tableland,the capacities of vegetation recovery were similar to the shady slope after some artificial measures (i.e.,land formation,annular enclosure and irrigation) were adapted.The artificial vegetation recoveries were unsuitable in sunny slope where the natural recovery should be considered.