东北漫岗黑土区防护林带分布对浅沟侵蚀的影响

东北漫岗黑土区坡耕地浅沟侵蚀非常严重,防护林带体系作为坡耕地的重要组成部分,势必会对浅沟侵蚀过程产生影响。本文以漫岗黑土区黑龙江鹤山农场典型小流域为研究对象,基于Quickbird高精度遥感影像和数字高程模型,结合实地调查结果,对小流域内防护林带的分布规律和浅沟侵蚀规律进行了分析,并探讨了防护林带布局对坡面浅沟侵蚀的影响。结果表明:在横坡耕作的坡面上,临界汇水区范围内林带的个数与临界坡长、临界汇水面积呈显著正相关,即增加林带个数、减小林带间距可以增大临界坡长和临界汇水面积,而研究区防护林带间距过大,大于该区浅沟发生的临界坡长,并且防护林带间断有利于浅沟的发育;同时,坡耕地垄向由于受到防护林带影响而与其走向一致,使垄沟笔直穿过低洼水线,形成局部顺坡垄,间接诱发浅沟侵蚀。因此,通过增加横坡耕作坡面上防护林带个数、缩小林带间距、加强林带的管护和更新,同时对不合理的防护林带进行必要的调整,才能有效防治坡面浅沟侵蚀。

Effect of Shelterbelts Distribution on Ephemeral Gully Erosion in the Rolling-hilly Black Soil Region of Northeast China

The ephemeral gully erosion in cultivated slope lands in rolling-hilly black soil region of northeast China is very serious.As one of the most important parts of cultivated slope lands,the shelterbelt system would inevitably affect the process of ephemeral gully erosion.Based on the Quickbird high-precision remote sensing and digital elevation model,and combination with field survey results,the rules of shelterbelts distribution and ephemeral gully erosion in a small watershed of rolling-hilly black soil region in Heshan Farm of Heilongjiang Province were analyzed.The results showed that the critical slope length and catchment area for the ephemeral gully development in the region were positive linearly correlated with the number of shelterbelts in the catchment of the ephemeral gully,which means increase of the number of shelterbelts and decrease of the distance between the shelterbelts could increase the critical slope length and catchment area,then decrease the possibility of ephemeral gully erosion occurrence.The distance between the shelterbelts in the study area was too large to prevent the slope from ephemeral gully erosion,and the breaks of shelterbelts benefited the development of ephemeral gully.In addition,ridge culture was adopted in the region,the direction of furrows were affected by the shelterbelts,some of the furrows straight through low-lying water line,and some furrows along slope were formed,which induced the ephemeral gully erosion.Thus increase of the number of shelterbelts in the slope lands,decrease of the distance between shelterbelts,enhancing the management and update of shelterbelts,and adjusting unreasonable distribution of shelterbelts could be the way to prevent ephemeral gully erosion.