草原化荒漠草本植物对人工施加磷素的响应  

Response of herbaceous vegetation to phosphorus fertilizer in steppe desert

作　　者：苏洁琼[1,2] 李新荣[1] 冯丽[1,2] 回嵘[1,2] 黄磊[1,2] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所沙坡头沙漠试验研究站,兰州730000 [2]中国科学院研究生院,北京100049

出　　处：《生态学报》2012年第1期93-100,共8页Acta Ecologica Sinica

基　　金：中国科学院重要方向项目(KZCX2-EW-301);国家自然科学基金资助项目(40930636)

摘　　要：利用人工外源施加磷素的野外试验研究了荒漠区草本植物群落物种丰富度、多度、盖度、生物量、优势种株高等生态学特征对不同磷素水平的响应。试验结果表明:在水肥充足的施肥当年,物种丰富度和多度均随着施磷水平的提高而下降,50 g/m2的高肥处理下二者均显著低于不施肥的对照(P<0.05)。盖度和地上部生物量在施肥当年均随着施磷水平的提高而增加,50g/m2的高肥处理下二者与对照相比其增幅分别达到了47.59%和360.49%(P<0.05)。而在干旱的年份,即施肥后第2年,物种丰富度、多度、盖度和地上部生物量在不同磷素水平下其和对照间的差异均不显著(P>0.05)。另外,外源磷素的施加会降低荒漠区草本植物的地下部生物量;而优势种草本植物茵陈蒿、多根葱、无芒隐子草和锋芒草株高对不同水肥耦合模式的响应存在种间差异。可见,在湿润的年份,外源磷素的施加会降低荒漠区草本植物群落的物种多样性,但会提高其种群生产力;而在干旱的年份,水分的缺乏抑制了磷肥残效的作用,外源磷素施加后对荒漠区草本植物群落物种多样性和种群生产力的影响不显著。表明水分为荒漠区草本植物生长的第一非生物限制性因子,水、肥可共为限制性因素。In desert ecosystems,low soil moisture and high soil alkalinity decrease phosphorus（P） bioavailability,which results in a scarcity of soil P.Low soil P availability limits plant growth,development and reproduction,and consequently P is one of the most important limiting factors for vegetation growth and restoration in desert ecosystems.Furthermore,productivity of most plant communities increases following nutrient addition,while species diversity shows different responses to nutrient addition.Nevertheless,little attention has been directed towards identification and quantification of P pools in water-limited desert ecosystems,and results of P fertilization experiments in non-arid regions are not applicable to arid regions receiving 200 mm annual precipitation.The aim of this study was to understand the effects of artificial P addition on the vegetation structure of herbage synusia and to offer a solid basis for long-term restoration and scientific management of desert ecosystems.We selected the herbaceous vegetation in steppe desert on the southeastern margin of the temperate Tengger Desert,northern China,as a case study and collected data through field surveys after artificial addition of P fertilizer in spring.Phosphorus fertilizer was added in the first year,in which the annual precipitation was 271 mm（1.4 times the average annual precipitation）.In the second year,no P was applied and the annual precipitation was 127 mm.The species,number of individuals,height and coverage were recorded monthly.Using these data,we analyzed the response in species richness,abundance,coverage,biomass and the height of frequent species of the desert herbaceous vegetation community to artificially amended P under ambient precipitation.Species richness and abundance decreased gradually with increasing level of P fertilization in the first year,and both variables did not change significantly in response to 12.5 and 25 g/m2 fertilization（P 0.05）,but decreased significantly with 50 g/m2 fertilization treatment,compared wit

关 键 词：草原化荒漠 草本层片 磷肥 物种多样性 生物量 

分 类 号：Q948[生物学—植物学]