放牧强度对帕米尔高原草毡表层及草地营养和水分利用的影响  

Effect on incrassation of mattic epipedon and pasture nutrient- moisture using by grazing in Pamir meadow

作　　者：赵翠珍 

机构地区：[1]克州环境监测站,新疆阿图什845350

出　　处：《干旱环境监测》2015年第3期130-134,共5页Arid Environmental Monitoring

摘　　要：在帕米尔高原高寒草原地区,选择了4个自然放牧梯度、处于3种典型退化阶段的草地为研究对象,进行了土壤草毡表层加厚引起的系统氮、磷分配和水分利用的变化过程的研究。结果表明,随着放牧强度的增加,草地禾本科植物逐渐减少,蒿类植物成为优势种群,土壤草毡表层逐渐加厚,从新疆银穗草+硬叶苔草群落的3.02±0.53 cm发育到高山绢蒿、西藏亚菊群落阶段的8.24±0.53 cm;矮生嵩草群落使系统生长需要的氮、磷养分数量急剧增加,分别从12 g/m2到23 g/m2、0.84 g/m2到1.7 g/m2,成为生物养分固定累积于土壤;同时致密加厚的、特别是老化死亡的草毡表层的存在,使土壤水分的渗透速率从新疆银穗草+硬叶苔草群落的1.94 mm/min降低到小嵩草群落的1.38mm/min,使系统接受自然降水的能力大大减弱,水分的利用效率极低,而根系数量的急剧增长导致需水量的增加,土壤湿度逐渐降低,降幅最大达到18.85%。草毡表层加厚导致的营养供求失调、干旱胁迫是引起高寒草地退化的内在原因之一。The distribution of N - P and the moisture variation caused by incrassation of the mattic epipedon together with its relationship to pasture degradation by grazing in Pamir meadow were studied at the Pamir. From 2010 -2014, the plot pasture was maintained with a relatively stable grazing intensity and had formed Obvious differences in surface character and species component. As grazing intensity increased the Sagebrush gradually replaced the Gramineae as the dominant community, the depth of mattic epipedon increased, driven by the special biological characteristics of Sagebrush. It developed from 3.02 ± 0. 53 cm in the Leucopoa olgea ＋ Carex moocroftii community to 8.24 ± 0.53 cm in the Pamir community. Meanwhile the N - P nutrient amount needed by the system rose rapidly from 12 to 23 g/m^2 and from 0.84 to 1.7 g/m^2 respectively. The nutrients were mostly used for root growth which became biologically fixed and accumulated in the soil. The ratio of saturation was reduced froml. 94 mm/min in the Leucopoa olgea ＋ Carex moocroftii community tol. 38 m/min in the Pamir community due to compaction and incrassation , especially of the dead attic epipedon, which resulted in a considerable decrease in the ability to accept precipitation . The rapid growth and quantity of roots caused an increase in the water requirement, so that soil moisture was gradually reduced with the smallest amplitude reachingl8. 85%. The maladjustment of nutrient supply and demand together with drought enhancement caused by the thickening mattic epipedon maybe one reason for degradation in Pamir meadows.

关 键 词：高寒草地 草毡表层 放牧强度 土壤养分 渗透速率 

分 类 号：X176[环境科学与工程—环境科学]