土地退化方法应用初步研究——以闽西沙县东溪流域为例

综合运用^１３７Ｃｓ、土壤磁测等新技术手段,结合土壤结构水稳性、ＣＥＣ等部分土壤理化指标,对闽西沙县东溪流域坡地不同部位的土地退化特征进行初步的定量研究,结果表明：①土壤中^１３７Ｃｓ含量与坡度呈很强的对数关系（Ｒ＝－０８３）,表明土地退化随坡度的增加而加剧；②土壤表层磁化率富集系数与坡度呈较强的对数关系（Ｒ＝－０６３）,表明土地退化随坡度的增加而加剧；③不同地貌部位以及不同的土地利用类型之间,其土壤部分理化指标,在不同的显著性水平上,呈现一定的退化特征。

THE APPLICATION OF THE NEW METHODS ON LAND DEGRADATION STUDY A CASE STUDY ON DONGXI RIVER BASIN, WESTERN FUJIAN, CHINA

The attempts which apply the alternative methods for estimating rapidl soil erosion rates to elusidate the relationship between the land use types and land degradation has been made. The 137Cs measurement, magnetic susceptibility, aggregate stability, and the soil properties have been employed in Dongxi River Basin, a mountainous area of western Fujian. The results reveal that: (a)A plot of 137Cs inventory(Y) against slope angle(X) showing a strong inverse log log relationship(r=-0 83) indicates that much stronger soil erosion occurs on steeper slopes;(b)average soil loss(in thichness of top soil per year) in the past 30 years for arable slope crest, arable slopes and tea plantation slopes are 1.6, 10.4 and 8.0 mm/year respectively; (c)the surface layer enrichment factor of magnetic susceptibility(Y) in soil also shows an inverse log log relationship(r=-0 63) which indicates a similar tendency with the relationship between the 137Cs inventory(Y) against slope angle(X); and (d)the physical and chemical properties of soil among different land use types show different degraded characteristics at different significance levels.