长期集约经营条件下雷竹林土壤微生物量的变化

雷竹Phyllostachys praecox是一种优良的笋用竹种．长期强度经营虽然带来了显著的经济效益．但是也导致竹林提早退化。在浙江省临安市横畈镇和西天目乡的雷竹样地采样调查，选取栽植时间分别为5，10，15a的雷竹林地土壤，以及刚由水稻Oryzasativa田改种为雷竹林的土壤（1a），旨在研究长期集约经营对雷竹林土壤微生物量的影响。结果表明，横畈镇和西天目乡的雷竹林经过长期集约经营之后，均显著增加了土壤（0～20cm）中有机碳、全氮、碱解氮、全磷及有效磷的质量分数，而pH值则随着经营年限的延长而降低。长期的集约经营显著降低了土壤微生物量碳、氮质量分数以及微生物量碳／有机碳、微生物量氮／全氮的比值：土壤微生物量磷呈现出先增加后降低的趋势，而微生物量磷，全磷的比值则同样随经营年限的延长而逐渐下降。长期施肥和覆盖措施降低了土壤微生物的活性．使土壤生物学总量衰退．促使雷竹林提前退化。表4参22

Soil microbial biomass in long-term and intensively managed Phyllostachys praecox stands

Phyllostachys praecox,a favorite bamboo species with high economic value from its edible shoots,has often been intensively managed resulting in great gains for the farmers,yet compared to traditional management there is a serious bamboo degradation problem.The objective of this study was to analyze the effects of long-term intensive management on soil microbial biomass in P.praecox stands.A field survey was conducted with soil samples taken from 5-,10-,and 15-year old intensively managed bamboo stands in He...