川西高寒山地灌丛草甸土壤水文效应特征

Characteristics of soil hydrological effects of alpine shrub meadow in western Sichuan

土壤入渗和持蓄水分的水文功能是森林保持水土、涵养水源的基础.为揭示不同海拔和坡向土壤理化性质及水文效应的差异,选择折多山高寒山地灌丛草甸土壤为研究对象,测定土壤基本物理性质、持蓄水性能和入渗性能.结果表明:(1)坡向和海拔对土壤物理性质的影响主要作用于淋溶层;土壤容重总体表现为淀积层>淋溶层,半阴坡>半阳坡,最大为4000 m半阴坡(1.21 g/cm^(3)),最小为4000 m半阳坡(0.77 g/cm^(3)),土壤总孔隙度则表现出相反规律.(2)土壤自然贮水量、最大持水量、毛管持水量和最小持水量表现为淋溶层>淀积层,土壤涵蓄降雨量和有效涵蓄量表现为半阴坡<半阳坡;土壤最大持水量、毛管持水量、涵蓄降雨量和有效涵蓄量均表现为4000 m半阳坡淋溶层最高,分别为1336(±24.66)、1016(±14.14)、710(±26.98)和390(±14.14)t/hm^(2).(3)土壤初渗速率和稳渗速率总体表现为淋溶层>淀积层,半阴坡<半阳坡;土壤渗滤系数K10最大为4200 m半阳坡淋溶层(7.41 mm/min),最小为4000 m半阴坡淀积层(0.57 mm/min).可见,不同海拔和坡向间土壤物理性质及水文功能有明显分异特征,土石混合介质土壤水文功能研究可能是今后该地区土壤水文的研究重点.

The hydrological functions of soil infiltration and water retention are foundational to forest water and soil conservation.In order to investigate the differences in soil physical and chemical properties and hydrological effects at different altitudes and slope aspects,alpine shrub meadow soil from Zheduo Mountain,China,was selected for characterization.The basic physical properties,water holding capacity,and infiltration performance of the soil were studied.The results were as follows:(1)The influence of slope aspect and altitude on soil physical properties was mainly observed on the leached layer.Soil bulk density was generally higher in the sediment layer and semi-shady aspects than in the leaching layer and semi-sunny aspects;it was maximal in the 4000 m semi-shady slope samples(1.21 g/cm^(3)),and minimal in the 4000 m semi-sunny slope samples(0.77 g/cm^(3)),whereas total soil porosity showed the opposite pattern.(2)The natural soil water storage capacity,maximum water holding capacity,capillary water holding capacity,and minimum water holding capacity were higher in the leaching layer than in the sedimentary layer,whereas soil storage rainfall and effective storage capacity were higher in semi-sunny aspects than in semi-shady aspects.Soil maximum water holding capacity,capillary water holding capacity,cumulated rainfall,and effective cumulated storage capacity were highest in the leached layer at semi-sunny slope aspects below 4000 m,with values of 1336(±24.66),1016(±14.14),710(±26.98),and 390(±14.14)t/hm^(2),respectively.(3)The initial soil infiltration rate and steady infiltration rate were generally higher in the leaching layer and semi-sunny slope than in the sedimentary layer and semishady slope.The maximum value of the soil infiltration coefficient,K10,was observed in the 4200 m semi-slope leaching layer(7.41 mm/min)and the minimum value was observed in the 4000 m semi-shady slope sediment layer(0.57 mm/min).We observed a clear differentiation of soil physical properties and hydrological functions under different altitudes and slope aspects.Research on soil hydrological functions of soil-rock mixed media may be the focus of future research on soil hydrology in this area.