【摘要】 探讨基于乌苏里江流域土地利用结构变化对乌苏里江界河的水土流失的影响,无疑对于乌苏里江界河的国土防护具有极其重要的意义。本文以地形图、MSS和TM影像数据提取乌苏里江流域1954年、1976年和2000年土地利用结构信息。应用一个改进型的土地利用结构的特征指标,分析了乌苏里江流域近50年来土地利用结构变化对于乌苏里江的水土流失的影响。近50年来,由于以沼泽地为代表的水土保持权重值高的地类面积日益缩小、破碎化程度呈增高趋势,而旱地等低权重值地类面积迅速扩张、连通性增强,改进型土地利用结构特征指标呈下降趋势,3个时期的指标值分别是18.21937、9.72415、2.57338,表明近50年来乌苏里江流域的土地利用结构变化朝不利于乌苏里江界河的水土保持发展,乌苏里江界河承受日益增大的水土流失危险性。更多还原

【Abstract】 The effects of land use structure on soil and water loss of national boundary river basin is very important for territory protection.Applying a redesigned index of land use structure,the effect of land use structural change on water and soil loss in Wusuli River basin was analyzed.There are many researches about the simple relationship between single land use type and soil erosion.But there are few researches about relationship between multiple land use types and soil erosion.To analyze quantitatively the effects of land-use structure on soil erosion,a characteristic index for land use structure is proposed by Ni Jin-ren to reflect the comprehensive impacts of various types of land use,which is defined as the sum of products of the weight assigned to each type of land use and its corresponding area percentage over the total for the region under concerned.Land-use structure includes not only the percentage but also the fragmentation of each land use type.In addition,previous researches show that one land use type may have different effects on a river because of the different distance between the river and the land.So the authors redesigned the characteristic index for land use structure,and the formula isSII=∑ni=1[β_iA_i/(F_i×D_i)×100] which SII is the redesigned index,β_i is the weight assigned to each type of land use,A_i is area percentage of each type of land use,F_i is the fragmentation index of each land use type,and D_i is the distance between each type of land use and the central line of the research river. Information of land use structure in Wusuli River watershed during last 50 years was extracted from relief map,MSS and TM.Results show that the redesigned index of land use structure is decreasing.The reason is that the land cover types with high conservation weight such as marsh have been reduced with ascending fragmentation degree,while the land cover types with low conservation weight such as arid land have been extended with descending fragmentation degree.The redesigned indices of land use structure of Wusuli River are 18.21937,9.72415 and 2.57338 in the year 1954,1976 and 2000,respectively.So it is concluded that the soil and water loss in Wusuli River is becoming serious because of the dynamic change of land use structure.At the same time,reducing the area of farmland is not the only way to conserve the soil and water in Wusuli River;reducing the fragmentation of land use types such as wetland and grassland is a way out.更多还原