典型黑土区地形与垄作特征对切沟发育的影响

Effects of topography and tillage characteristics on gully development in the Mollisol region

【目的】明确黑土区坡耕地切沟分级特征,明晰地形条件与耕作垄向对切沟发育的影响,揭示自然条件与人类耕作扰动下切沟侵蚀发育机理,为切沟侵蚀精准防控与黑土地保护利用提供关键科学支撑。【方法】文章以典型黑土区坡耕地为研究区,基于2018年高分一号遥感影像数据和地形数据,采用目视解译结合野外详查的方法,获取研究区切沟长度、坡度、垄向角、垄作坡长、垄作坡度等指标,结合地貌学水系分级原理划分切沟等级,并分析人为垄作因素与自然因素对切沟发育的影响。【结果】(1)研究区发育的234条切沟可分为4个等级,其中1级切沟数量最多,沟长随着切沟等级提升而呈增加趋势;(2)斜垄耕作占比最多、横垄(80~100°)次之,1级沟主要分布在横垄耕作(38%),0~300 m垄长(81%)和0~2°垄作坡度范围内(48%);(3)切沟数量随着海拔的增加出现先增加后减小的趋势,在海拔210~220 m切沟最多,随着海拔的增加,垄作坡长和垄向角呈增大趋势,而垄作坡度呈现减小趋势;(4)切沟数量在坡度2~4°最多,随着切沟坡度的增加,垄向坡长和垄向角度减小,垄作坡度增大。【结论】分析黑土区切沟分级特征、空间分布及其影响因素,探究地形条件与垄作因素对切沟发育的影响,为切沟精准防控和黑土地保护与可持续利用提供了重要依据。

[Purpose]This study aims to clarify the gully classification characteristics in typical sloping farmland in the Mollisol region,clarify the influence of topogtaphy and tillage characteristics on gully development,reveal the gully erosion mechanism under the effect of natural forces and anthropic tillage disturbance,and provides basis for the prevention and control of gully erosion and the protection and utilization for the Mollisol region.[Method]The article taked typical sloping farmland in the Mollisol region as the study area.Based on 2018 GF-1 remote sensing images and 1∶10000 DEM,we manually visualized the indexes of furrow length,slope,ridge length,and slope,by the combination with detailed field investigation,and the gully system was also classified.[Result](1)The 234 gullies can be divided into 4 grades,among which the number of grade 1 gullies was the largest,and the average length of gullies increases with the increasing grade;(2)The proportion of askew tillage was the highest,followed by horizontal tillage(80~100°),and grade 1 trench gully was mainly distributed in horizontal tillage(38%),0~300 m tillage length(81%)and 0~2°(48%);(3)The number of gullies increased first and then decreased with the increasing altitude,and reached the maximum at 210~220 m.Tillage length and angle increased with the increasing altitude,while tillage slope increased and then decreased;(4)The number of gullies reached the maximum at a 2~4°slope.With the increase of the gully slope,the tillage slope length and angle decreased,and the tillage slope increased.[Conclusion]Analyzing the classification characteristics,spatial distribution,and influencing factors of gullies in the Mollisol region,exploring the effects of topography and tillage factors on the gully development,provides significant support for further gully prevention and control and the protection and sustainable utilization of the Mollisoil.