摘要
坡耕地土壤侵蚀导致土壤质量降低,并因此造成对作物产量的不利影响。利用土壤侵蚀测定的137Cs示踪技术,结合土壤理化分析,研究了川中丘陵区紫色土坡耕地土壤侵蚀所引起的土壤再分配对养分空间变异性的影响。结果表明,川中丘陵区坡耕地土壤侵蚀是水蚀和耕作侵蚀共同作用的结果,强烈的耕作导致坡上部发生最为严重的土壤侵蚀。土壤侵蚀对土壤特性的空间变异性产生深刻影响,坡上部土壤有机质和养分贫瘠,而在坡下部相对富集;土壤有机质、全N、碱解N、有效P、K以及土壤粘粒含量在不同坡位之间出现显著差异。反映净余土壤再分配速率的137Cs面积浓度与这些土壤理化特性均有密切的相关性。因此,137Cs面积浓度可以作为表征侵蚀坡地土壤综合质量的指标。
Severe soil erosion on cultivated sloping land in hilly areas of Sichuan has resulted in deterioration of soil matter （ SOM）, total N, P, K, available N, P, K and particle size fraction were collected at 10 m intervals along a transect of the hillslope. Effects of soil erosion on soil nutrient loss were studied by using 137Cs technique, and the relationships between 137Cs-derived soil redistribution rates and soil nutrients were established over the cultivated sloping land in hilly areas of Sichuan, China （30°26N, 104°28E）. SOM, total N, available N, P, K and the 〈0. 002mm soil particle size fraction were smaller at upper and middle slope positions where lower ^137Cs concentrations were present （i. e. soil erosion rates were greater） than at downslope positions where ^137Cs concentrations were higher （i. e. soil erosion rates were less）. The lowest ^137Cs concentrations were found in the hilltop, showing that besides water erosion, tillage erosion also contributed to soil losses, and intensive tillage was mostly responsible for severe erosion at upper slope positions. There were significant differences in soil OM, total N, available N, P, K and the 〈0. 002mm soil particle size fraction between different slope segments, and these properties were significantly correlated with slope length. These soil properties were also significantly correlated with ^137Cs concentration, indicating that both ^137Cs and nutrient concentrations varied with topographical changes. The variation in soil properties was strongly influenced by erosion-induced soil redistribution, and therefore ^137Cs concentrations mirroring soil redistribution rates would be considered as an integrated indicator of soil quality.
出处
《生态学报》
CAS
CSCD
北大核心
2007年第2期459-464,共6页
Acta Ecologica Sinica
基金
国家重点基础研究发展规划(973)资助项目(2003CB415202
2006CB403204)~~
关键词
^137Cs示踪
土壤侵蚀
土壤养分
坡耕地
紫色土
^137Cs technique
soil erosion
soil nutrient
purple soil
cultivated sloping land
