三江源区不同利用方式草地生物量及土壤养分特征

以三江源区玛多县高寒草原、退化高寒草原和垂穗披碱草人工草地为研究对象,研究了不同土地利用方式对地上、地下生物量以及土壤有机碳、全氮、全磷、有效氮、有效磷含量的影响。结果表明:总生物量的高低排序为高寒草原人工草地退化高寒草原,人工草地和退化高寒草原的总生物量分别仅为高寒草原的32.9%和22.8%,人工草地对地上植被的恢复效果较好,地上部生物量最高,为高寒草原地上生物量的359.2%,但对地下生物量的恢复并不理想,0~10cm地下生物量仅为高寒草原的11.5%。3种利用方式草地土壤碳氮磷养分含量均处于较低水平;退化和人工种植草地0~10cm土层的有机碳、全氮、全磷、有效氮、有效磷含量明显较高,而10cm以下土层的各样分含量明显下降;退化对下层土壤的全磷和有效磷含量没有明显的影响,不同利用方式草地的全磷和有效磷含量在不同土层的变异也不明显。

Study on plant biomass and soil nutrients under different land use patterns in Three-river Headwater Area

Three land use patterns in Maduo county located in Three-river Headwater Area.including alpine steppe,degraded alpine steppe and sowed grassland with Elymus nutans were selected to study the effects of land use pattern on above ground biomass,and underground biomass,soil organic carbon,total nitrogen,total phosphorus,available nitrogen and available phosphrous content.The results showed that the rank of total bio-mass in three land use patterns was alpine steppe> sowed grassland >degraded alpine steppe.The total bio-mass of sowed grassland and degraded alpine steppe accounted for 32.9% and 22.8% of that of alpine steppe re-spectively.The sowed grassland had good recovery effect on the above ground vegetation because of its highest aboveground biomass,which accounted for 359.2% of that of alpine steppe,however,the underground biomass of sowed grassland was lower,which accounted for 1 1 .5% of that of alpine steppe.Soil nutrients of three land use patterns were all lower level.Soil organic carbon,total nitrogen,total phosphorus,available nitrogen and a-vailable phosphorus in 0~10 cm soil both in degradation and artificial grassland were all higher,but these nutri-ents below 10 cm soil were all lower.Degradation had no obvious impact on soil total phosphorus and available phosphorus below 10 cm soil,and soil total phosphorus and available phosphorus under different land use pat-terns did not show obvious changes along the soil profile.