吉林省侵蚀沟分布与环境要素的关系

目的]探求与侵蚀沟空间分布密切的环境因子,揭示其分布特征,为侵蚀沟发育规律研究及治理提供理论依据。方法]利用遥感调查和抽样调查相结合的方式,基于GIS分析功能,对吉林省6个区域共23个调查单元(小流域)内侵蚀沟进行了调查与汇总分析,研究沟壑密度、沟壑裂度等与环境要素关系。结果](1)6个区域沟壑密度大小顺序为:敦化(16.30km/km~2)辽源(6.51km/km~2)梅河(5.55km/km~2)伊通(4.67km/km~2)九台(3.54km/km~2)前郭(2.21km/km~2);(2)敦化地区沟壑裂度随坡度增加先稳定后急剧降低;前郭地区沟壑裂度随坡度的增加而增加;辽源、梅河、伊通、九台4个地区沟壑裂度均随坡度的增加呈现先增加后减少的趋势,沟壑裂度最大值除辽源发生在6°~9°外,其他3个地区均发生在3°~6°;(3)沟壑密度随坡度的增加而增加,二者存在较强的线性关系,相关系数达0.755,研究中符合这一规律的样本占总体的83%。(4)集水区形状系数对沟壑密度具有一定的规律性影响,但这只体现在九台地区,主要表现为沟壑密度随形状系数的增加而增加;(5)6个地区沟壑密度与集水面积呈一元二次函数关系,29.39hm~2为沟壑密度发生变化的临界值。结论]吉林省内分异特征总体表现为由西向东和由北向南增加的趋势。不同地区沟壑裂度随坡度变化呈现出不同规律,集水区长度、平均宽度与侵蚀沟各特征指标均无显著相关性。

Relationship Between Distributions of Erosion Gully and Environmental Factors in Jilin Province

Objective] The distribution characteristics of erosion gully in Jilin Province and the environmental factors that are relevant with the spatial distribution were explored to provide theoretical bases for gully evolution and its harness.Methods] Using methods of remote sensing and field investigation, gullies in 23 small watersheds distributed in six districts of Jilin Province were analyzed by GIS, mainly referred to the indices of the gully density and gully crack degree. Whereby, their relationships with environmental factors were studied.Results] (1) The gully density in the six districts had a size rank as:Dunhua(16.30 km/km²) > Liaoyuan(6.51 km/km²) > Meihe(5.55 km/km²) > Yitong(4.67 km/km²) > Jiutai(3.54 km/km²) > Qianguo(2.21 km/km²). (2) Gully crack degree had different regional associations with slope steepness:in Dunhua district, with the increase of slope steepness, the gully crack degree was stable initially and then drastically reduced; In Qianguo District, it kept an increasing tendency. In districts of Liaoyuan, Meihe, Yitong and Jiutai, variation characterized with preceding increase and later decline was more normal. The maximum of gully crack degree was found at slopes of 6°~9° in Liaoyuan district, at slopes of 3°~6° in other three districts. (3) About 81% of the investigated gullies, its density was found closely dependent upon slope steepness, their correlation coefficient was 0.734. (4) In Jiutai District, the gully shape was found associated with the gully density,the gully density exhibited an increasing tendency with slope steepness increasing. (5) Evolution of gully with respect to the density obey a quadratic function with catchment area as independent variable, in all the six districts, the point of inflection was at 29.39 hm² of catchment area.Conclusion] The gully densities increased from the west to the east and from the north to the south of Jilin Province. The dependence of gully crack degree upon slope steepness varied in different districts. No significant correlations between gully density and indices as gully length, gully width, and other gully indicators were found.