荒漠草原典型群落土壤粒径和养分的分布特征及其关系研究

Relationship between Soil Particle Size Distribution and Soil Nutrient Distribution Characteristics in Typical Communities of Desert Grassland

为了明确荒漠草原区土壤机械组成与养分的关系,以宁夏盐池荒漠草原4种典型群落为研究对象,通过对不同群落(柠条、沙蒿、蒙古冰草、短花针茅)表层(0~5cm)、亚表层(5~10cm)和深层(10~15cm)土壤粒径分布分形(PSD)、养分含量的动态变化分析,揭示荒漠草原区土壤结构与土壤养分的相关性。结果表明:(1)4种典型群落土壤PSD均呈正态分布,不同群落间的土壤PSD差异显著,粒径100~500μm颗粒含量对PSD影响最大,不同群落间的差异大于不同生境间或不同土层间。(2)4种典型群落除全磷(TP)外,其余土壤全肥均随土壤深度增加呈降低趋势,且冠下大于丛间,表现出荒漠草原区特殊的"肥岛"聚集效应,不同群落间分布特征均表现为:柠条>短花针茅>蒙古冰草>沙蒿,速效养分含量相对较高,各群落均达到适宜水平。(3)土壤养分与土壤PSD显著相关,除速效磷(AP)外,其余土壤养分与土壤分形维数(D)均呈正相关关系,粒径100~250μm、250~500μm颗粒与土壤养分呈显著或极显著负相关关系,土壤中的黏粒、粉粒在有机无机胶结过程及土壤良好的结构维持中起主要作用。

In order to define the relationship between the soil mechanical composition and the nutrient in desert grassl and ,we studied four typical grassl and communities in desert grassl and of Yanchi Country,Ningxia.We analyzing the changes of soil particle size distribution(PSD) and the nutrient content of soil surface(0-5cm),subsurface(5-10cm),deep soil layer(10-15cm)in different communities(Cara-gana korshinskii,Artemisia ordosica,Agropyron mongolicum,Stipa breviflora).We also explored the correlation of soil structure and soil nutrients.The results showed that:(1)soil particle size distribution of four typical grassl and communities showed a trend of normal distribution, and significant difference in different communities(P<0.05).The content of particle size of 100-500μm had a significant influence of PSD.The different communities showed bigger difference than that of different habitats and different layers;(2)In addition to the total phosphorus(TP),soil nutrients decreased gradually with the increase of soil depth.The canopy is greater than the plexus and showed a special'fertilizer isl and effect'in desert grassl and .And distribution characteristics of different communities showed:C.korshinskii>S.breviflora>A.mongolicum>A.ordosica.The content of available nutrient was relatively higher and all communities reached the appropriate level;(3)Soil nutrient was significantly correlated with PSD.In addition to the available phosphorus(AP),the soil nutrients were positively correlated with soil fractal dimension(D).The particle sizes of 100-250μm and 250-500μm were significantly negatively or extremely significantly negatively correlated with the soil nutrients(P<0.05 or P<0.01).The clay and silt play a main role in the process of organic and inorganic cement and maintaining agood soil structure.