Effects of the expressway on the soil-plant systems in the Longitudinal Range-Gorge Region

Abstract

Taking Da-Bao expressway in the Longitudinal Range-Gorge Region (LRGR) as an example, the effects of the expressway on three kinds of soil-plant systems along the road are analyzed by seven types of indexes, which are soil nutrient, heavy metals of soil, soil moisture and pH of soil, plant nutrient, heavy metal of plant and plant diversity. Firstly, through comparing typical sampling points and their contradistinguished points, the effects of the expressway on single index is analyzed and discussed; secondly, interactions among the expressway and all kinds of indexes are discussed with correlative analysis; finally, the range and intensity of effects on three systems are analyzed with gray related analysis. All results show that 1) within the range of effect by expressway, the forms of expression of all indexes are different to the interference of expressway. 2) Expressway can cause the accumulation of HMS and HMP, especially in the farmland system; and bring a little alkalization of the soil, especially in the shrub system. 3) Expressway is the most important influencing factor of HMS, SM, HMP and PD in the forest and shrub systems, but only HMS and HMP in the farmland system. To the indexes of insignificant correlation with road, expressway works indirectly through the effect chains of the system. Comparing with three kinds of soil-plant systems, effects mostly concentrate on the areas of 10 m from the expressway in the forest and farmland systems, and on the area of 30 m on the shrub system.