摘要
土壤流失程度与人类对土地的干扰程度和干扰方式息息相关。本文通过测定不同耕垦时间、不同退耕时间及不同植被恢复方式的黄土坡面137Cs的含量,研究137Cs流失程度与坡面利用历史之间的相关关系。结果表明,不同时期开垦的坡耕地上137Cs含量与开垦时间、坡度呈线性关系,与坡长的相关性不明显,其回归方程为:X=2356.79?22.77t?35.53S;不同时期的撂荒地坡面上137Cs含量的变异系数为80.11%。137Cs含量与退耕时间、坡度、坡长等因素分析表明,137Cs含量与退耕时间的关系最为密切。退耕坡面上不同植被恢复方式也直接影响坡面137Cs浓度。本研究中137Cs的流失情况从总体上来说,自然恢复<直接还生态林<直接还经济林。可见坡面137Cs含量主要与土地利用历史关系密切。
There are close linkages between soil loss degree and soil disturbance degree by human. So it is a key problem to know that how human activity affects soil loss. In this paper, to analyse the correlation of ^137Cs loSS degree with hillslopes＇ cultivated histories, the concentrations of ^137Cs on different kinds of loessial hillslopes with different cultivated histories, abandoned ages and different patterns of reforestation are studied. The result shows that there is a linear relationship among ^137Cs areal concentrations, cultivation ages and slope gradients. The regressive equation is as follows： X=2356.79-22.77t-35.53S. Variant coefficient of ^137Cs areal concentration is 80.11% among hillslopes with different abandonment ages. It is also deduced that ^137Cs areal concentration is affected primarily by abandonment ages of hillslopes. The ^137Cs loss rates of hillslopes with different vegetation restoration manners show significant differences, as a whole, autogenic restoration 〈 constructing ecological forest 〈 constructing economic forest in Yangou watershed. The history of land utilization is therefore considered to be the main cause that affects ^137Cs area concentrations on hillslopes.
出处
《核技术》
EI
CAS
CSCD
北大核心
2005年第8期607-612,共6页
Nuclear Techniques
基金
中国科学院"知识创新"项目(KZCX1-06)
中国科学院"西部之光"项目及长沙理工大学基金资助
