油蒿与臭柏沙地生物结皮对土壤理化性质的影响

根据沙地固定情况和生物结皮发育程度选取油蒿(Artemisia ordosica)群落中半固定沙地初期阶段发育的生物结皮(SF-E)、半固定沙地较厚的生物结皮(SF-L)、新固定沙地生物结皮(NF)、中期固定沙地生物结皮(MF)、老固定沙地生物结皮(OF)和苔藓结皮(MOSS)6种类型生物结皮和臭柏(Sabina vulgaris)群落中丘间地(IV)和丘顶(TV)2种生物结皮,比较了不同类型生物结皮对土壤理化性质的影响。结果表明:不同类型生物结皮表层土壤有机质、总N及土壤粒度组成存在差异。随着生物结皮从MS—SF-E—SF-L—NF—MF(MOSS)—OF—IV—TV的发育,表层土壤有机质、总N及粉粒质量分数呈现递增的趋势,而土壤粗砂粒质量分数随生物结皮的发育而递减;表层土壤富集的养分及细颗粒组分有向下位移的现象,导致表层下10 cm处土壤养分质量分数及颗粒组成也随生物结皮的发育程度而发生与表层土壤趋势相同的变化。总之,生物结皮的发育能显著增加表层土壤有机质、总N及土壤细颗粒成分。

Influences of Biological Soil Crusts on Physicochemical Properties of Soil in Artemisia ordosica and Sabina vulgaris Communities

Six kinds of biological soil crusts were selected in Artemisia ordosica community according to the situation of sand surface and the stage of biological soil crusts,namely early-successional biological soil crust in semi-fixed sand dune(SF-E),later-successional biological crust in semi-fixed sand dune(SF-L),new fixed sand dune(NF),medium-term fixed sand dune(MF),old fixed sand dune(OF) and biological soil crust dominated by moss(MOSS).Moreover,two kinds of biological soil crusts in inter dune(IV) and sand top(VT) were selected in S.vulgaris community.Moving sand dune(MS) was selected as the control to compare the influences of different kinds of biological soil crusts on soil physical and chemical properties.Results showed that organic matter,total nitrogen and grain size both in surface soil and in 10 cm soil depth were different.Organic matter,total nitrogen and silt content in the surface soil increased with the development of biological soil crusts from MS to SF-E,SF-L,NF,MF(MOSS),OF,IV,and TV,while the coarse sand content in the soil decreased.Nutrients and fine particles in topsoil were enriched by biological soil crusts downward,which leaded to the same changing trend of soil nutrients and particle composition at 10 cm below the surface as the surface soil changing with the development of biological crusts.The development of biological soil crusts could significantly increase the contents of organic matter,total nitrogen and fine particles accumulated in the top soil.