锡林浩特土壤颗粒分形特征与草原植物生物量的相关性研究

为研究土壤分形维数是否会影响草原植物生长,本文多角度地剖析了草原土壤分形维数与植物生物量的相关性。2012年在锡林浩特地区采集了88个土样,分别计算分形维数值,采用线性回归、相关性分析等统计方法,分析土壤分形维数与土壤各粒级颗粒含量、植物生物量之间的关系。结果表明：①土壤分形维数与粗砂粒含量存在显著负相关,与细砂粒含量不相关,与粉粒、黏粒含量呈显著正相关,说明土壤分形维数对于各粒级含量的反映程度不同,主要反映黏粒含量;②根据植物的形态特征和适应方式,将草原植物划分为不同类型的功能群,生活型功能群中多年生丛生禾草、小半灌木、一、二年生植物的生物量与土壤分形维数呈正相关（R值分别为0.345,0.674,0.238,P<0.05）,说明土壤分形维数可以表征这三类功能群植物的生物量累积情况;生态类型功能群中,旱生植物、旱中生植物与分形维数并无直接相关性,而旱生植物生物量与黏粒含量呈正相关,旱中生植物生物量与粉粒含量呈显著正相关,鉴于颗粒含量与分形维数间的关系,即其生长与土壤分形维数呈正相关,多年生根茎禾草、多年生杂类草、中旱生植物、中生植物的生物量与土壤分形维数并无明显相关性。

Correlation between fractal characteristics of soil particles and biomass of steppe plants in Xilinhot

In order to determine whether soil fractal dimension affects the growth of steppe plants,we analyzed the correlation between soil fractal dimension and plant biomass. Eighty-eight soil samples were collected in the Xilinhot area in 2012 and we used linear regression,correlation analysis and other statistical methods to analyze the relationship between soil fractal dimension and particle content,soil fractal dimension and plant biomass. We found that soil fractal dimension had a significant negative correlation with coarse sand content,no significant correlation with fine sand content,and an extreme significant correlation with silt and clay. To some extent,soil fractal dimension could reflect the content of soil particles,especially clay content;according to morphological characteristics and the ways adapted to the natural environment,grassland plants were divided into different functional groups,among life-form functional groups the biomass of perennial bunch grasses,semi-shrubs,annuals and biennials were positively correlated with soil fractal dimension （R was respectively 0.345,0.674 and 0.238） and indicates that soil fractal dimension probably impacts the accumulation of biomass in these three functional groups. Among functional groups of water ecological types,xerophytes and intermediate mesophytes had no significant correlation with soil fractal dimension,but xerophytes were positively correlated with clay particle content and intermediate mesophytes biomass was positively correlated with silt content. In view of the relationship between particle content and fractal dimension,the growth of these plants were positively correlated with soil fractal dimension. Perennial rhizome grasses,forbs,intermediate xerophytes and mesophytes had no significant correlation with soil fractal dimension.