黄土丘陵区柳枝稷生物量与土壤水分的动力学研究

通过在黄土高原半干旱地区种植柳枝稷，构建生物量与土壤水分的动力学关系模型。结果表明：在年降水量大于328mm的安塞地区，柳枝稷生长稳定；当年降水量少于328mm，柳枝稷收获（降水量580mm）每年超过1．4次，柳枝稷会衰败。当植被与土壤水分的相互作用较强时，植被会衰败，因此引种时必须选择与土壤水分作用相对较弱的植物。模型两个稳定状态共存表明，气候改变（干旱）或人类活动（放牧）对植被将产生不可逆的影响。

Dynamic research on relationship between switchgrass (Panicum virgatum) biomass and soil water in hilly region on loess plateau

The dynamic relationship between the biomass of switchgrass and the soil water content in arid and semiarid area was investigated in this paper. The analysis of the model indicated that with the precipitation r>328 mm, the growth of switchgrass in Ansai county was stable. The switchgrass would decline when the annually precipitation was less than 328 mm, or it was harvested more than 1.4 times a year. The dynamic analysis indicated that the flora would decline if the interaction between the flora and soil water were strong. The species that interacted with soil water comparatively weaker must be paid more attention in the introducing planting experiments. The coexistence of stable states suggested that climatic changes (like drought) or human activities (like overgrazing) would lead to a long and possibly irreversible degraded state.