摘要
采用137Cs和210Pbex双核素示踪方法,结合GIS技术,在典型黑土区面积为28.5hm2的小流域上,研究了林带对小流域土壤侵蚀和泥沙沉积的影响。结果发现:小流域内的林带能在一定程度上减少土壤流失,林带前、后特别是带前表现为泥沙沉积,而带后一定距离上,土壤侵蚀会加剧;坡面较缓和等高线与林带夹角较小的林带拦沙效益高;在小流域两条防护林带和沟口地埂的作用下,小流域呈现侵蚀-沉积-侵蚀-沉积的模式。近50年来,平均每年沉积在两条林带前后60m范围内的泥沙占小流域总泥沙沉积量的18.8%;在100年的时间尺度上,平均每年沉积在林带前后的泥沙占流域年泥沙总沉积量的7%左右。在50年和100年的时间尺度上,小流域的泥沙输移比分别为53%和78%。
Two radionuclide tracers （i. e. , 137Cs and 210Pbex） were used in combined with GIS technique to investigate the impact of shelterbelts on soil erosion and sediment deposition at a catchment with area of 28.5 hm2 in the typical black soil region, northeastern China, and some meaningful conclusions were drawn. The two shelterbelts in the catchment could reduce soil loss at a certain degree, and sediment deposition usually occurred before and behind the shelterbelts, leading to less erosion intensity before the shelterbelts. Inversely, erosion became severe behind the shelterbelts at a certain distance. In comparison to the lower shelterbelt, the upper shelterbelt with local gentle topography and less angle between the shelterbelt and the contours had higher sediment trap efficiency. Impacted by the two lines of shelterbelts and the earth bank at the catchment outlet, the catchment presented an erosion-deposition-erosion-deposition pattern. In recent 50 and 100 years, the sediment amounts annually deposited along the shelterbelts at distances of 30 and 60 meters occupied 18. 8% and 7% of the total deposited sediment in the catchment, respectively. The sediment delivery ratios derived by 13% Cs and 210 Pbox methods were 53% and 78%, respectively. Factors influencing sediment trap efficiency of shelterbelts are multiple, further study is urgently required to further discuss the impact of shelterbelts on soil erosion which affected by multiple factors.
出处
《陕西师范大学学报（自然科学版）》
CAS
CSCD
北大核心
2018年第1期104-110,共7页
Journal of Shaanxi Normal University：Natural Science Edition
基金
国家自然科学基金(41571271)
关键词
东北黑土区
农田防护林带
核素示踪
土壤侵蚀
泥沙沉积
black soil region of northeastern China
agricultural field shelterbelt
radionuclides
soil erosion
sediment deposition
