增温和隔离降雨对杉木幼林土壤养分和微生物生物量的影响

摘要

在全球气候变化背景下,中国亚热带地区独特的地理位置决定了该地区在气候变暖的同时还会伴随干旱,但对于增温和隔离降雨的研究多集中在中高纬度地区,对亚热带等低纬度地区的研究较少.本研究通过设置对照、增温、隔离降雨和增温+隔离降雨4种处理,探讨增温和隔离降雨对杉木幼林表层土壤养分和微生物生物量的影响.结果表明:增温和隔离降雨均可使土壤养分有效性发生变化,增温使土壤可溶性有机碳、可溶性有机氮、有效磷浓度有所增加,而隔离降雨主要影响了N有效性,表现为土壤铵态氮浓度显著下降(P<0.05).增温后微生物生物量碳、氮均显著下降(P<0.05),增温和隔离降雨的交互作用对微生物生物量磷影响显著.在亚热带地区,氮磷养分有效性有可能是全球气候变化背景下影响土壤微生物生物量的重要因素,未来还需结合野外原位实验做进一步的研究.%Under the background of global climate change,the unique geographical location of subtropical zone in China determines that the region will be drought while warming.However,studies on soil warming and precipitation exclusion are mainly set in the middle and high latitudes,with few researches been done in low latitude areas.We investigated how soil warming and precipitation exclusion influenced soil nutrients and microbial biomass of surface soil of young Chinese fir(Cunninghamia lanceolata)plantation.Four treatments were set up,viz.control(CT),warming(W),precipitation exclusion(P),warming and precipitation exclusion interaction(WP).Results showed that warming and precipitation exclusion changed the soil nutrient availability.Warming increased the concentrations of dissolved organic C(DOC),dissolved organic N(DON)and available phosphorus,which can be absorbed and utilized easily by microorganisms.Precipitation exclusion mainly affected the N availability,which showed a significant decrease of ammonium N concentration(P<0.05).Microbial biomass C,N and P decreased significantly under warming(P<0.05).The interaction of soil warming and precipitation exclusion influenced soil microbial biomass P(MBP)significantly.Under global change background,the nutrients availability of N and P may be the important factors which affect the soil microbial biomass in the subtropical regions.