近50年冀北高原土地利用变化的土壤生境效应

区域性土壤生境的变化，很大程度上取决于该区土地利用及其覆被的变化．通过冀北高原近50年不同时段的资料分析证实，大片天然草场无序垦为耕地的利用变化及伴随的管理粗放，致土壤生境发生系列负面效应，土壤养分逐年下降．50年中，该区土壤有机质，N、P、K全量及速效态量分别以36．90％、67．77％、44．44％、34．15％、32．22％、58．90％、35．29％的降幅趋势性地下降；砂、粉、粘三项表征土壤物性特征的不同土粒含量则以18．24％、19．55％和12．29％升降皆有的幅度变化．这一结果揭示，为确保区位重要、生境脆弱区的土地质量不因利用变化和随时间推移而下降，永续处于动态平衡，务必科学管理，技术举措到位。

Effect of land-use change on soil habitat in north Hebei plateau during last 50 years

The change of soil habitat in an area depends on the land-use and cover change in the area to a great extent.Analysis of soil data in north Hebei plateau during last 50 years confirmed that the land-use change,i.e.,the disorder reclamation of a large stretch of natural grassland into cultivated land and the extensive farming,had a series of negative effects on the soil habitat,and made the soil nutrients decreased.During last 50 years,the total and available amount of soil organic matter,N,P,and K decreased by 36.90%,67.77%,44.44%,34.15%,32.22%,58.90% and 35.29%,respectively,and the granulometric contents of sand,silt and clay also varied by 18.24%,19.55%,and 12.29%,respectively,which revealed that in order to ensure the land quality in the regionally important but vulnerable habitat area against the effect of land-use change and its possible degradation with time and to be in sustained dynamic equilibrium,it is necessary to take reasonable fertilization and reliable technical measures.