岷江柏林下土壤养分特征及种群间差异分析

Characteristic and Population Difference Comparison of Soil Nutrients Under Cupressus Chengiana Forests

对现存于川西6个县的岷江柏林下土壤养分状况及其空间差异性比较研究表明,土壤表层(0～20cm)有机质、全N、全P、碱解N、速效P、速效K和阳离子交换量均以马尔康居群最高,其次为金川、小金、丹巴居群,理县和茂县居群较低,土壤全K和土壤pH恰好相反,茂县居群较大,马尔康居群较小.从土壤的垂直变化看,除全K和土壤pH外,其它土壤养分均为表土层大于底土层.从相关性分析看,岷江柏林下土壤全N、全P、碱解N、速效P和CEC与土壤有机质呈极显著相关,土壤速效养分主要受全量养分控制,土壤养分指标地理空间差异较大,通过岷江柏林土壤养分指标的相关性分析,马尔康岷江柏居群土壤养分指标综合性能最好,其次为理县、金川、丹巴、小金岷江柏居群,最差的为茂县岷江柏居群.岷江柏林下养分差异是植被状况、地形条件、保护管理措施和人为干扰状况等多种因素综合作用的结果.

The study was conducted in Cupressus chengiana forests in western Sichuan （6 counties） with relation to geographical distribution. Soil organic matter （OM）, total N, total P, alkali-hydrolyzable N, available P, available K and cation exchange capacity （CEC） in topsoil （0--20 cm） in Cupressus chengiana forests were the highest in Barkam （MRK） population, and Jingchuan （JC）, Xiaojing （XJ）, Danba （DB） populations were in the next place, Lixian （LX） and Maoxian （MX） popalations were lowest. Yet the change trend of soil total K and pH were reverse with other nutrients in all populations, that is to say, soil soil total K and pH were the highest in MX population and were the lowest in MRK population. Other nutrients except total K and pH were higher in topsoil than that in downsoil. Soil total N, total P, alkali-hydrolyzable N, available P and CEC were significantly correlative with soil OM, soil available nutrients were mainly controlled by soil total nutrients. Soil nutrients had significantly spatial difference in all Cupressus chengiana populations. Based synthetical analy- sis on soil nutrients, soil integrated fertility in Cupressus chengiana forests was the highest in MRK population, JC, XJ, DB populations were in the next place, LX and MX populations were the worst. Spatial differences of soil nutrients under Cupressus chengiana forests were mainly affected by conditions of vegetation, topographic condition, measures of protection and management and conditions of human-induced disturbance.