摘要
为研究干旱荒漠地区土壤水分特征的变化规律并探讨土壤水分特征曲线拟合模型的适宜性,以古尔班通古特沙漠南缘丘间地为研究对象,应用压力膜仪测定了丘间地剖面各土层(0—150cm)的土壤水分特征曲线,结合土壤容重、颗粒分布及饱和含水率等性质,分析了丘间地不同土层水分特征和孔隙大小的分布状况,明确了Gardner模型和van Genuchten模型拟合的适用性。结果表明:(1)丘间地剖面砂质土壤释水量伴随吸力呈规律性变化,低吸力段(0~100kPa)各土层水分特征曲线走势陡直,释水性强;中高吸力段(100~1 500kPa)曲线趋于平缓,持水性强。水分曲线特征与其物理性质一致,各土层物理性质差异较小,曲线的差异也较小。(2)丘间地剖面各土层大孔隙由上到下不断增加且20—40cm土层的小孔隙最多,有助于春季积雪融化迅速入渗到土壤里贮存,对植物吸收利用水分有重大意义。(3)两模型都能很好地拟合丘间地的土壤水分特征曲线,VG模型的拟合效果优于G模型,但G模型形式简单、参数少且易于求解,更便于实际应用。
In this paper,we evaluated the variations of soil water and explored the suitability of the soil water characteristic curve fitting model in interdune lowland at the southern edge of Gurbantunggut Desert.Using the pressure membrane apparatus,we measured the soil water characteristic curves at different soil depths（0—150cm）in desert land.Combined with bulk density,grain size and saturated water content,the distributions of soil water characteristics and pore size in different soil layers were analyzed,and the applicability of Gardner model and van Genuchten model fitting was defined.Our data showed that the sandy soil release rate varied regularly with soil water suction rate in interdune lowland.Soil water characteristic curves in different soil layers showed a steep trend and strong water release in low suction range（0—100kPa）,while they presented a smooth and slow trend,with a high water holding ability in high suction range（100—1 500kPa）.The soil moisture characteristic curve was consistent with its physical properties.The distribution of soil pore size varied regularly,with increasing the proportion of large pores from the top to the bottom soil layer and the small pores held the biggest ratio in 20—40cm soil layer,which was conducive to the rapid infiltration of the spring snow melt into the soil.In addition,our results found that both the two models fitted well with the measured data in this region.The VG model was better than G model in fitting the soil water characteristic curve in interdune lowland,but G model was simple in form,with few parameters and easy solving,which was much more convenient for practical application.
出处
《水土保持学报》
CSCD
北大核心
2017年第1期166-171,共6页
Journal of Soil and Water Conservation
基金
重大科学研究计划项目“973”(2013CB429905)
国家自然科学基金项目(41601107,41671032,U1303181)
