东北黑土区不同垄向耕地沟蚀与地形耦合规律

The Coupling Laws Between Gully Erosion of Cultivated Lands with Different Ridge Directions and Terrain in Northeast Black Soil Region of China

东北黑土区在长期高强度开垦连作下,侵蚀沟切割耕地地表现象严重。以黑龙江省宾县的两个典型乡镇为研究区,基于GIS和RS技术,采用全局空间自相关、样方网格等方法,综合垄向、侵蚀沟、地形数据探究区域尺度下垄向分布及不同垄向耕地沟蚀与地形因子耦合规律。结果表明:(1)不同乡镇沟蚀空间集聚程度不同,主导性垄向耕地内的侵蚀程度最高;(2)垄向在耕地上的分布有很强的空间自相关性,不同的垄向空间分布是对地形条件的反馈体现,合理的垄向空间分布会起到降低沟蚀密度的作用;(3)除糖坊镇斜垄外,不同垄向耕地沟蚀密度随海拔的升高呈现先增大后减小的趋势。糖坊镇不同海拔级优势垄向规律性不强,三宝乡整体上任意海拔级斜垄耕作最优;(4)坡度与坡长交互作用显著。两乡镇表现为"小坡度"+"小坡长"或"小坡度"+"大坡长"条件横垄耕作最优,"大坡度"+"小坡长"或"大坡度"+"大坡长"条件斜垄耕作最优;(5)黑土区漫川漫岗地带斜垄耕作更具水土保持作用。

With the long-term over-cultivating and continuous cropping in the northeast black soil region of China,it has been a severe problem that the erosion gullies cut up the cultivated land surface.We took two towns in Bin County of Heilongjiang Province as the typical areas.The spatial distribution and the coupling laws between gully erosion of cultivated lands with different ridge directions and terrain in regional scale were studied based on the GIS and RS technology,integrated ridge direction,erosion gully,DEM data,global spatial autocorrelation,sample of grid and so on.The results showed that：first,the spatial agglomeration of gully erosion was not the same in different towns,erosion degree of the dominant ridge direction in cultivated land was the most serious;second,the distribution of ridge direction in cultivated land showed an obvious spatial autocorrelation,the different spatial distribution of ridge direction was the feedback toward the terrain conditions,and the reasonable spatial distribution of ridge direction played a role in reducing gully density;third,gully density of different ridge directions in cultivated lands increased first and then decreased with the elevation rising in addition to askew ridge of Tangfang Town.The regularity of optimal ridge direction in different elevation levels was not obvious in Tangfang Town,askew ridge tillage in any elevation level was optimal in Sanbao Town;fourth,the interaction between slope length and slope gradient was significant,showing that the horizontal ridge tillage was optimal under the condition of‘small slope gradient＇＋‘small slope length＇or‘big slope gradient＇＋‘small slope length＇,and the askew ridge tillage was optimal under the condition of‘small slope gradient＇＋‘big slope length＇or‘big slope gradient＇＋‘big slope length＇in both towns;fifth,askew ridge tillage has significant effect on water and soil conservation in rolling hill regions of black soil area.