陕北无定河流域土壤侵蚀时空演变

发布时间：2018-05-06 07:13

  本文选题：降雨侵蚀力 + 土壤侵蚀　； 参考：《环境科学研究》2017年09期

【摘要】：为了深入认识陕北无定河流域土壤侵蚀时空演变过程及其与降雨和植被NDVI变化的关系,采用基于RUSLE(修正通用土壤流失方程)的土壤侵蚀评估方法,开展流域土壤侵蚀时空分布及其与降雨、植被NDVI的关系研究.结果表明:(1)2000—2014年无定河流域多年均土壤侵蚀模数为457.90 t/(km2·a),呈波动增加过程.流域土壤侵蚀以微度侵蚀为主,占流域总面积的88.35%,其他土壤侵蚀等级面积比例随等级升高而减少.研究时段内除微度侵蚀面积比例减少外,其他土壤侵蚀等级面积比例均呈增加过程,并且侵蚀面积年变化速率也由微度侵蚀的0.52%降至剧烈侵蚀的0.01%.(2)无定河流域西北部土壤侵蚀程度最低,西南部其次,东南部最高,与其地貌类型及降水量沿东南—西北方向递减有关,但均反映出流域2000—2014年土壤侵蚀的增加过程.研究时段内流域不同土壤侵蚀等级间面积及比例转移主要由低等级土壤侵蚀类型转为相邻高等级土壤侵蚀类型.(3)无定河流域土壤侵蚀与降水量、侵蚀性降雨量、降雨侵蚀力呈显著正相关(P0.01),相关系数分别为0.90、0.95和0.98,而与植被NDVI的关系不显著.研究显示,降雨变化尤其是侵蚀性降雨(≥12 mm/d)增加是陕北无定河流域土壤侵蚀增强的主要原因.
[Abstract]:In order to deeply understand the temporal and spatial evolution of soil erosion and its relationship with rainfall and vegetation NDVI changes in Wuding River basin of Northern Shaanxi, a soil erosion assessment method based on RUSLE-based modified universal soil loss equation was adopted. The temporal and spatial distribution of soil erosion and its relationship with rainfall and vegetation NDVI were studied. The results showed that the average modulus of soil erosion in Wuding River Basin from 2000 to 2014 was 457.90 t/(km2 a ~ (-1), which showed an increasing process of fluctuation. Soil erosion in the watershed was dominated by micro-erosion, accounting for 88.35% of the total area of the basin, and the proportion of other soil erosion grade areas decreased with the increase of the grade. The proportion of soil erosion grade area was increased in the period of study except for the decrease of the proportion of micro-erosion area. And the annual change rate of erosion area also decreased from 0.52% of micro-erosion to 0.01% of severe erosion. The soil erosion degree in the northwest of Wuding River Basin was the lowest, followed by the southwest and the southeast, the highest in the southwest, the highest in the southeast, and the lowest in the northwest of Wuding River Basin. It is related to the geomorphologic type and precipitation decreasing along the southeast-northwest direction, but all reflect the increasing process of soil erosion in the basin from 2000 to 2014. During the study period, the area and proportion transfer between different soil erosion grades in the basin mainly changed from low grade soil erosion type to adjacent high grade soil erosion type. 3) soil erosion and precipitation and erosive rainfall in Wuding River Basin. There was a significant positive correlation between rainfall erosivity and vegetation NDVI, and the correlation coefficient was 0.90,0.95 and 0.98, respectively, but there was no significant relationship between rainfall erosivity and vegetation NDVI. The results show that the change of rainfall, especially the increase of erosive rainfall (鈮，

本文编号：1851316