东祁连山高寒草地返青期不同草地型土壤磷的分布特征

Distribution Characteristics of Soil Phosphorus at Turning Green Stage in Different Alpine Grasslands in the Eastern Qilian Mountains

试验在东祁连山选择代表性的七种高寒草地型为研究对象,在返青期对其土壤微生物量磷(MBP)、全磷和速效磷及其相关性进行了研究。结果表明,土壤全磷和速效磷分别介于1.0～2.0g/kg和14.3～52.9mg/kg,样地间差异较大,且速效磷上层高于下层,除禾草草地外草本草地显著高于灌丛草地(P<0.05);土壤微生物量磷及其对土壤全磷贡献率分别介于22.46～64.27mg/kg和1.75%～4.59%,且上层高于下层;微生物量磷与微生物量碳氮除嵩草草地外均呈极显著正相关(P<0.01),草地型对该相关性的影响不明显,该相关性由土壤微生物本身或其群落结构决定;土壤微生物量磷与土壤化学性质关系密切,植物群落对此相关性影响不明显;微生物量碳磷比和微生物量氮磷比分别介于4.38～21.50和1.07～3.88,草地型间差异显著(P<0.05),说明在不同草地型间土壤微生物量及群落结构均有差异。

Rhododendrons brushland （DJ）, Salix cupularis brushland （GL）, Dasiphoru fruticosa brushland（JI.）, Polygonum vivi parum grassland（ZY）, Grass steppe（HC）, Swamp grassland（ZZ） and Kobresia grassland（SC）, which delegated seven different alpine grassland types in the Eastern Qilian Mountains of the Qinghai-Tibetan Plateau, west of China, were selected to investigate their soil phosphorus （including microbial biomass phosphorus（MBP）, total soil phosphorus and available phosphorus ） and their correlationship. The total soil phosphorus and the available phosphorus which were different between the types of grassland varied from 1.0-2.0g/kg and 14.3-52. 9mg/kg, respectivaly. The content of available phosphorus were more at the upper layer than those at lower layer and there were significant difference between the grassland and brushland （P〈0.05） except HC. The MBP and the contribution of MBP to total phosphorus, which were more at the upper layer than those at lower layer, ranged from 22.46 -64.27mg/kg and 1.75 %-4.59%. respectively. The MBP showed significant positive correlation at P 〈0.01 with microbial biomass carbon and nitrogen under seven sites, which showed that the grassland types was not important for the correlation and the microorganism themselves or their community structure were key to the correlation. The MBP showed significant correlation with soil chemical property, but the plant community affected a little on the correction. The MBC/MBP and the MBN/MBP that varied from 4. 38-21.50 and 1.07-3.88 respectively were significant difference among the sampling sites （P〈0.05）, which showed that the values of soil microbial biomass and the community structure were different between the grassland types.