高寒草甸不同类型草地土壤机械组成及肥力比较

研究了青藏高原高寒草甸不同类型草地土壤机械组成和土壤养分变化特征,并用相关分析探讨了土壤理化特征、土壤机械组成对不同草地类型群落物种组成、生物量变化的响应。结果表明:不同草地类型土壤机械组成分布大致是矮嵩草草甸:粉粒>细砂粒>粘粒>粗砂粒;高山嵩草草甸:细砂粒>粉粒>粘粒>粗砂粒;藏嵩草沼泽化草甸:细砂粒>粉粒>粘粒>粗砂粒;金露梅灌丛:粉粒>粘粒≥细砂粒>粗砂粒。矮嵩草草甸、高山嵩草草甸为粉砂质粘壤土,藏嵩草沼泽化草甸为壤土,金露梅灌丛为壤质粘土。矮嵩草草甸、高山嵩草草甸和金露梅灌丛土壤颗粒分布相对比较均匀(除藏嵩草沼泽化草甸外),主要集中在<0.5mm的范围内,土壤粘粒含量普遍大于20%。土壤全量养分和速效养分以及土壤物理特征均影响着高寒草甸不同草地类型土壤质量和土壤结构。土壤结构和养分状况是判断高寒草甸生态系统生态功能维持的关键指标之一。

Comparison of soil mechanical composition and soil fertility at different grassland types in alpine meadow

Soil is a fundamental component in every terrestrial ecosystem,and the structure and function of plant community were affected by soil environment conditions,and changing of the plant species composition and species diversity resulted from difference of soil environment in plant community succession.This study was conducted to examine characteristics of soil mechanical composition,soil fertility and their relationship with plant community biomass,species composition at different alpine meadow.The results showed that soil mechanical composition distribution is thick sand>fine sand>clay>silt in Kobresia humilis meadow;fine sand >thick sand>clay>silt in K.pygmaea meadow;fine sand>thick sand>clay>silt in K.tibetica swamp meadow;thick sand>clay≥fine sand>silt in Potentilla fruoticosa shrub.The soil of K.humilis meadow belongs to silty clay loam soil,K.tibetica swamp meadow belongs to loam soil,Potentilla fruoticosa shrub belongs to loamy clay soil.The distribution of soil particles were relatively uniformity in K.humilis meadow,K.pygmaea meadow and Potentilla fruoticosa shrub except for K.tibetica swamp meadow,and mainly concentration in < 0.5 mm ranges,the content of soil clay particles > 20%.Soil quality and soil structure in different grassland types in alpine meadow were influenced by soil total nutrient,available nutrient and soil physical characteristics(soil bulk density,soil moisture etc).Soil structure and soil nutrient condition are the important factor for maintaining alpine meadow ecosystem function.Those results confirmed that the reasonable grazing intensity and the proper management measures are effective methods to protect soil quality in degradation region of alpine meadow.