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为了系统研究黄土高原丘陵沟壑区土壤侵蚀演变过程及其规律,以黄土高原纸坊沟流域为例,在GIS的支持下,运用RUSLE估算了该流域1938—2010年间18个年份的年侵蚀量和侵蚀强度,分析了70多年来流域土壤侵蚀时空演变过程。结果表明:1)纸坊沟流域的土壤侵蚀随时间呈四次抛物线变化,侵蚀模数由1938年的7 584.39t/(km2.a)猛增到1958年的4万6 392.56 t/(km2.a),随后总体呈递减趋势,到2010年侵蚀模数降至5 150.80 t/(km2.a)。2)1938年中度以下侵蚀面积占流域总面积的52.99%;1958—1978年以剧烈侵蚀为主,占流域总面积的67.05%,其中1958年高达78.61%;1978—1998年侵蚀强度有所下降,微度侵蚀面积占流域总面积比例达到29.27%;1999年以来,微度侵蚀面积达到3.85 km2,剧烈侵蚀面积仅占流域总面积的8.96%。经过30多年的综合治理,该流域生态环境明显改善,但沟谷陡荒坡侵蚀依然严重,是今后水土流失治理的重点区域。
In order to systematically study the process and law of soil erosion evolution in the hilly and gully regions of the Loess Plateau, taking the area of the Zhifanggou watershed in the Loess Plateau as an example, RUSLE was used to estimate the annual erosion amount and the soil erosion in 18 years from 1938 to 2010 Erosion intensity, and analyzed the spatial and temporal evolution of soil erosion over the past 70 years. The results showed as follows: 1) Soil erosion in the area of Qifanggou watershed changed quadratically with time, and the erosion modulus increased sharply from 7 584.39 t / (km 2.a) in 1938 to 46 392.56 t / (km 2 .a), followed by an overall decreasing trend. By 2010, the erosion modulus has dropped to 5 150.80 t / (km2.a). 2) The area under moderate erosion accounted for 52.99% of the total area of the basin in 1938; the area was dominated by severe erosion in 1958-1978, accounting for 67.05% of the total area of the basin, of which 78.61% in 1958; and the erosion intensity in 1978-1998 As a result, the area of micro-erosion accounts for 29.27% of the total drainage area. Since 1999, the area of micro-erosion has reached 3.85 km2, and the area of severe erosion accounts for only 8.96% of the total area of the basin. After more than 30 years of comprehensive management, the ecological environment of the basin has been significantly improved. However, erosion on the steep slopes of the valleys is still serious, which is a key area for soil and water loss control in the future.