应用定位小区段面法实验和稀土元素示踪剂检测,选择吉林省长春市净月开发区和永吉县的两块黑土实验小区进行土壤侵蚀过程研究,探讨了稳定性稀土元素示踪法应用于黑土区土壤侵蚀、沉积、分布和发生过程研究的可能性,并计算出坡面不同部位的侵蚀量与相对侵蚀量,较好地描述降雨对坡面的侵蚀过程。实验表明,坡面的土壤侵蚀率随降雨时间而加大;7°~12°坡面的最大土壤侵蚀量出现在坡面中部和下部(为Nd、Sm和Eu所标记的坡段)。降雨时间和地形坡度大小影响土壤颗粒运动的速度和方向,是土壤侵蚀发生的主要因素。
By using fixed field profile experiment and Rare Earth Elements (REE) tracer technique, we studied the course of soil erosion on two parcels of black soil in Jingyue Economic Development District, Changchun City, and Yongji County, Jilin City, Jilin Province. The stable REE were used in tracing soil erosion, sedimentation, distribution and the possibility of erosion process in black soil area, soil erosion and the relative soil erosion of different parts of the slope were worked out, and effect of rainfall on the slope of soil erosion process described successfully. Experimental method is to trace elements evenly mixed with the soil, laid on the slope of the different terrain under test site, so that the entire process of rainfall runoff silt be done together with the relocation of its acquisition of sediment samples. The content of REE was tested in neutron activation method. Then soil erosion and the relative soil erosion of different parts of the slope were calculated according to concentrations of trace elements added into different parts of the slope and sediment collected after rainfall respectively. The experiment results show that the rate of soil erosion on the slope increases with rainfall period. Rain duration and slope are the two factors influencing soil erosion by affecting the movement speed and direction of soil particles. This paper concluded that: 1) artificial rainfall and natural rainfall field experiment showed that the slope erosion often turned around 10 min after rainfall, after that, the slope erosion rate became more stable, larger with the time increase. It could be considered that 10-15 min after rainfall is the best observation period for slope soil erosion study; 2) soil erosion occurred mainly in the middle and lower slope part (marked with Nd, Sm and Eu in the slope) in 7?-12 ? slope, which indicated that soil erosion is closely related to the slope and bands structure; and 3) the adoption of tracer REE for quantitative determination of the relative erosion in different terrain positions can provide an alternative method for vertical soil erosion. This method can not only monitor slope relative erosion in different terrain positions accurately, but also describes their distribution character objectively. Generally, the paper reveals the law of slope soil erosion intensity and provide new methods for the black soil erosion study.
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