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利用137Cs示踪技术,研究了宁南黄土高原阳洼流域土壤137Cs的空间分布和侵蚀特征。研究结果表明,流域137Cs背景值为1966.99Bq/m2,流域内不同土地利用方式下土壤137Cs比活度不同,且有比较明显的137Cs比活度分异。流域内林草地土壤剖面137Cs呈现指数分布模式,坡耕地剖面的137Cs则呈均匀分布模式。不同土地利用方式下土壤137Cs的面积活度表现为沟台>林草地>农耕坡地,其中农耕坡地、沟台地土壤侵蚀、沉积表现出较大的变异,变异系数达65%以上。阳洼流域土壤侵蚀模数与137Cs比活度呈现出相反的分布趋势,但都明显具有斑块状和条带状分布的特点。流域土壤以中、强度侵蚀为主,中、强度侵蚀面积占流域总面积的46%,在流域土壤侵蚀防治中坡耕地仍是治理的关键。
The 137Cs tracing technique was used to study the spatial distribution and erosion characteristics of 137Cs in Yangwa Watershed, South Ningxia. The results showed that the 137Cs background value of the basin was 1966.99Bq / m2. The specific activity of 137Cs in different land use patterns in the basin was different, and the specific activity of 137Cs was significantly different. The 137Cs in the grassland soil profile in the basin showed an exponential distribution pattern, and the 137Cs in the sloping landform showed a uniform distribution pattern. The area activities of soil 137Cs under different land use patterns showed as follows: Ditchi> grassland> agro-grassland. Soil erosion and sediment of agro-grassland and gully landform showed great variation with a coefficient of variation of over 65%. The soil erosion modulus and 137Cs specific activity in Yangwa Watershed showed the opposite trend, but both of them had the characteristics of plaque and banded distribution. Soil erosion in the watershed is mainly medium and intensive, and the medium and strong erosion areas account for 46% of the total drainage area. In the prevention and control of soil erosion in the watershed, sloping lands are still the key to harnessing.