不同海拔珙桐群落乔木物种多样性与土壤因子关系研究

 为探讨珙桐(Davidia involucrata)生长的最适海拔高度及其与土壤性质的关系,研究了四川卧龙自然保护区白泥岗地带不同海拔高度的珙桐群落的植物多样性及其根际土壤性质.结果表明,海拔1700 m的珙桐群落的物种多样性最高,1500~1700 m是适宜珙桐生长的海拔高度.珙桐根际土壤速效磷、速效氮、速效钾、有机质和含水量在3个土层深度上差异显著;整个地区土壤pH值变化范围小.腐殖质层土样1500~1700m 3个海拔土壤养分含量显著高于1800 m和1850 m 2个海拔;淀积层、母质层土壤养分在5个海拔间的变化规律性不强.相关分析表明,速效磷、速效钾和pH值与群落物种多样性无显著相关性,只有淀积层有机质、腐殖质层含水量与群落物种多样性显著相关,母质层速效氮和淀积层、母质层含水量甚至与群落物种多样性显著负相关.

A study of the relation between soil characteristics and tree species diversity of Davidia involucrate communities at different altitudes

Davidia involucrata,called the Chinese dovetree or handkerchief tree,is a relic deciduous species of Tertiary period.As the sole member of the family Davidiaceae,it is endemic to Southwestern China,but now also widely introduced elsewhere.In order to find out the relation between soil characteristics and optimal altitude for Davidia involucrate growth,a study of the rhizosphere soil characteristics and plant diversity of Davidia involucrate communities at different altitudes were finished.The study area was Bainigang Region of Wolong Nature Reserve and the obtained conclusions indicate that:plant diversity of Davidia involucrate community at 1700 m is the highest and the optimal altitudes for Davidia involucrate growth are from 1500-1700 m.Differences of soil characteristics among different horizons are significant which in terms of available phosphorus,available nitrogen,available potassium,organic matter and water content.The change of pH is little.In the region,as to the soil chemical property of humus horizon,the 1500-1700 m altitudes are remarkably higher than those of 1800 m and 1850 m altitudes.Among different altitudes,variation regulations of soil nutrient of illvuial horizon and parent material horizon soil layers could hardly be concluded.The pearson correlation shows that there is no relationship between the species diversity and available phosphorous,available potassium and pH.Only the organic matte of illuvial horizon and the moisture content of humus horizon are significantly correlated with the species diversity while the available nitrogen,moisture content of illuvial horizon and parent material horizon are significantly correlated with the species diversity negatively.