近50年冀北高原土地利用变化的土壤生境效应

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

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 5 0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 .5 0年中 ,该区土壤有机质 ,N、P、K全量及速效态量分别以 36 90 %、6 7 77%、4 4 4 4 %、34 15 %、32 2 2 %、5 8 90 %、35 2 9%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 2 4 %、19 5 5 %和 12 2 9%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 。

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.