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1、生态与农村环境学报2008,24(3):39-44JournalofEcologyandRuralEnvironment雨季红壤坡地油茶林土壤水势变化特征及耗水规律1,21①1田日昌,陈洪松,王克林(1.中国科学院亚热带农业生态研究所,湖南长沙410125;2.中国科学院研究生院,北京100049)摘要:利用野外定位观测数据,研究了雨季红壤坡地油茶林土壤水势变化特征及耗水规律。结果表明,土壤水势及其变异系数均为坡上大于坡下,坡上深度50cm、坡下深度40cm以上土层显著受到土壤蒸发和植物蒸腾的双重
2、影响,坡上、坡下深度90cm附近土壤水势变化大于相邻层次。土壤物理性质、根系分布对土壤水势影响显著,深度40、90cm分别为黏土层向砾石层、砾石层向网纹层的转变,水分容易积聚,根系易于向此靠近;吸水根(根直径<1mm)根干重与土层深度呈显著指数型相关,且在深度90cm处所占比例最大,达46.95%;吸水根干重所占比例与深层(70—110cm)土壤水势变化量呈明显正相关。通过零通量面分析,雨季持续干旱时段深层水分整体向上蒸发,但深度90cm处水势变化最大,证实土层深度90cm附近为雨季油茶林主要耗水
3、区域。关键词:红壤坡地;油茶林;土壤水势;根系;耗水中图分类号:S153.6文献标识码:A文章编号:1673-4831(2008)03-0039-06SoilWaterPotentialDynamicsandWaterConsumptionofOil2TeaCamelliaWoodsonSlopeLandofRedSoil1,211DuringRainySeason.TIANRi2chang,CHENHong2song,WANGKe2lin(1.InstituteofSubtropicalAgri
4、culture,Chi2neseAcademyofSciences,Changsha410125,China;2.GraduateUniversityofChineseAcademyofSciences,Beijing100049,China)Abstract:Basedonfixedfieldmonitoringdata,soilwaterpotentialdynamicsandwaterconsumptionintheoil2teacamel2liawoodsonslopelandofreds
5、oilwerestudied.Resultsshowthatduringtherainyseasonin2007soilwaterpotentialanditsvariationcoefficientattheupperslopewasgreaterthanatthelowerslope.Soils,0-50cmindepthintheupperslopeand0-40cminthedownslopewereobviouslyexposedtodualimpactsofevaporationand
6、transpiration,andthesoilwa2terpotentialat90cmindepthvariedmoresharplythaninothersoilhorizonsnearby.Soilphysicalpropertiesandrootdis2tributionaffectedsignificantlywaterpotentialandwaterconsumption.At40and90cmindepth,wherethesoilwasturn2ingfromclayhoriz
7、onintogravelhorizon,andfromgravelhorizontomottlinghorizon,respectively,watertendedtoaccu2mulateandrootswereapttoextendtowardsthere.Asignificantexponential2correlationbetweendryweightoffineroots(dr<1mm)anddepthofsoillayerwasobservedandabout46.95%ofthef
8、inerootsweredistributedinthe90cmsoillayer.Theproportionoffinerootswassignificantlyandpositivelyrelatedtosoilwaterpotential(70-110cm).Zerofluxplaneanalysisrevealedthatduringthecontinuousdryperiodintherainyseason,watermovedupwardsfromthedeeplay2
