降水量及N添加对宁夏荒漠草原土壤C∶N∶P生态化学计量特征和植被群落组成的影响  

Effects of precipitation and N addition on soil C∶N∶P ecological stoichiometry and plant community composition in a desert steppe of Ningxia, northwestern China

作　　者：朱湾湾 王攀 樊瑾 牛玉斌 余海龙[1] 黄菊莹[2] ZHU Wan-wan;WANG Pan;FAN Jin;NIU Yu-bin;YU Hai-long;HUANG Ju-ying(College of Resources and Environment,Ningxia University,Yinchuan 750021,China;Institute of Environmental Engineering,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学资源环境学院,宁夏银川750021 [2]宁夏大学环境工程研究院,宁夏银川750021

出　　处：《草业学报》2019年第9期33-44,共12页Acta Prataculturae Sinica

基　　金：宁夏高等学校科学研究项目(NGY2017003);国家自然科学基金项目(31760144和31360111)资助

摘　　要：为了解降水格局改变和大气氮(N)沉降增加背景下土壤碳(C)∶N∶磷(P)平衡关系的改变是否会影响到荒漠草原植被群落组成,基于2017年在宁夏荒漠草原设立的降水量(降水量减少50%、降水量减少30%、自然降水量、降水量增加30%和降水量增加50%)、N添加(0和5 g·m^-2·yr^-1)及其交互作用的野外试验,初步分析了土壤C∶N∶P生态化学计量特征和植物群落组成的变化趋势以及二者的关系。结果表明,增加降水量降低了土壤有机C、全N和N∶P。N添加及其与降水量的交互作用对土壤C∶N∶P生态化学计量特征的影响较小;适量增加降水量刺激了多数植物生长,提高了群落多样性。过量增加降水量导致猪毛蒿种群生物量急增,且N添加对降水量效应有促进作用,从而降低了群落多样性;土壤含水量、全N、有机C和N∶P与种群生物量关系较为密切,土壤含水量、有机C、C∶P和C∶N与多样性指数存在较强的相关关系。以上结果意味着降水量会通过调控土壤水分有效性,改变土壤与植物之间N和P的满足程度,从而对植物生长策略和群落多样性产生影响;短期N添加对土壤养分有效性影响较小。因此,还需通过长期的原位试验,对N添加及其与降水量交互作用下土壤C∶N∶P计量平衡与植物群落组成的关系进行深入探讨。Change in precipitation pattern and increase in atmospheric nitrogen(N)deposition are two important consequences of global change.Soil carbon(C)∶N∶phosphorus(P)ecological stoichiometry could reflect soil organic C level and N and P supply and thus would be closely related to plant growth.Previous studies have reported that both of the changes in precipitation and N deposition may lead to the decoupling of soil C∶N∶P ecological stoichiometry.In order to better understand whether the changes in soil C∶N∶P ecological stoichiometry could affect plant community composition under changing precipitation regimes and increasing atmospheric N deposition,we conducted a field experiment in a desert steppe of Ningxia,northwestern China,involving five precipitation treatments(50%reduction in precipitation,30%reduction in precipitation,natural precipitation,30%increase in precipitation,and 50%increase in precipitation)and two N addition treatments(0 and 5 g·m^-2·yr^-1)in 2017,and primarily explored the changes in both soil C∶N∶P ecological stoichiometry and plant community composition and their relationships in August,2018.It was found that increased precipitation led to decreases in soil organic C,total N,and N∶P,whereas N addition and its interaction with precipitation had little influences on soil C∶N∶P ecological stoichiometry;a moderate increase in precipitation stimulated the growth of most plants and thus increased community diversity.An excessive increase in precipitation resulted in a sharp increase of Artemisia scoparia biomass,combined with the positive effects of N addition,resulting in a reduction of community diversity.To a certain extent,soil water content,total N,organic C,and N∶P were closely related to plant population biomass,while soil water content,organic C,C∶P,and C∶N had closer relationships with diversity indices.Taken together,the results above indicate that precipitation could change N and P relationships between soil supply and plant demand through regulating soil water

关 键 词：干旱半干旱区 降水格局改变 大气N沉降增加 植物群落多样性 土壤C∶N∶P 

分 类 号：Q94[生物学—植物学]