CAJ | 학술논문

切沟侵蚀是土壤侵蚀的主要形式之一，严重威胁着土地资源。为了研究水平条带整地对切沟发育的影响，该研究基于间隔9 a的2期同时相QuickBird遥感影像，在陕西绥德县选取了32个小流域，应用GIS技术提取小流域内的沟缘线、植被覆盖度、坡度以及土地利用类型，估算研究区的切沟发育速率，并分析了水平条带整地对切沟发育的影响。结果表明：2004－2013年研究区内水平条带整地面积增加了16.96%，其中水平阶林地增加的最多，其次是水平梯田，而水平阶草地有所减少；32个小流域的切沟面积变化比例主要分布在0～6%，单位沟谷区面积增加比例为4.18%，且各小流域之间的差异明显；在该研究区内水平条带面积比例是影响切沟发育的最主要因子，相关系数达到?0.801。沟间地存在水平条带整地和植被覆盖度较高的情况下，地貌因子与切沟发育速率无显著相关性。水平条带整地类型的抑制切沟发展作用排序：水平阶林地＞水平阶草地＞水平梯田。该研究可为全面评价水平条带整地措施水土流失防治效果提供科学依据。
절구침식시토양침식적주요형식지일，엄중위협착토지자원。위료연구수평조대정지대절구발육적영향，해연구기우간격9 a적2기동시상QuickBird요감영상，재협서수덕현선취료32개소류역，응용GIS기술제취소류역내적구연선、식피복개도、파도이급토지이용류형，고산연구구적절구발육속솔，병분석료수평조대정지대절구발육적영향。결과표명：2004－2013년연구구내수평조대정지면적증가료16.96%，기중수평계임지증가적최다，기차시수평제전，이수평계초지유소감소；32개소류역적절구면적변화비례주요분포재0～6%，단위구곡구면적증가비례위4.18%，차각소류역지간적차이명현；재해연구구내수평조대면적비례시영향절구발육적최주요인자，상관계수체도?0.801。구간지존재수평조대정지화식피복개도교고적정황하，지모인자여절구발육속솔무현저상관성。수평조대정지류형적억제절구발전작용배서：수평계임지＞수평계초지＞수평제전。해연구가위전면평개수평조대정지조시수토류실방치효과제공과학의거。
Gully erosion is one of main forms of soil erosion threatening land resources. Conservation practices that can reduce rill and inter-rill erosion would be effective on control gully erosion but there is a lack of quantitative assessments. In order to access the effect of terrace on gully erosion, 32 small watersheds were selected randomly on the hilly and gully loess plateau in northern Shaanxi province, where cropland was returned to woodland or grassland in 2001 and terrace was the major conservation practices. Based on two QuickBird images with a 9-year interval and digital elevation model (DEM) with pixel size of 5 m, valley shoulder line and distribution of terrace and land-uses in the small watersheds was extracted by visual interpretation and with GIS technology. Average vegetation cover, local slope upslope drainage area and changes of the gully area from 2004 to 2013 were calculated to access the factors influencing gully growth. Gully area growth with cropland on terrace, woodland on narrow terrace, or grassland on narrow terrace on the upslope drainage area and gully area growth without terrace on the upslope drainage area were compared with statistical analysis method. The results showed that the proportion of terrace area on the upslope drainage area in the 32 small watersheds increased from 39.43% to 59.39% during the period from 2004 to 2013 with woodland on narrow terrace increased by 11.76% on average, cropland on terrace increased by 9.91% and grassland on narrow terrace decreased slightly. The gully area in 32 investigated small watersheds in 2013 increased by 0 to 6%with the average of 4.18%, as compared to 2004. Among the three factors related to gully growth rate investigated in this study, the terrace proportion in upslope drainage area was the most important. Gully area growth rate correlated significantly with terrace proportion in upslope drainage area and average vegetation coverage at the level of 0.01, with the Pearson’s correlation coefficients were-0.801 and 0.671, respectively;while the geomorphologic factors (AS2, where S is local slope gradient and A is drainage area), which was considered the predictor of gully initiation, were not related significantly to gully area growth rate owing to high vegetation coverage and high terrace proportion on the upslope drainage area, which reduced the kinetic energy of concentrated overland flow. 32 small watersheds were classified into 5 groups according to terrace proportion and vegetation types. Gully area growth rate in 5 groups of small watersheds increased in the following order:woodland on narrow terrace>grassland on narrow terrace>cropland on terrace>multiple vegetation on terrace>multiple vegetation without terrace. It indicates that the combination of engineering measures such as terrace and conservation vegetation achieves better effect than the single one. The results of this study can provide valuble information for evaluating the full effect of terrace on controlling soil erosion and making plan for gully control.