Effects of highway construction on soil quality in the Longitudinal Range-Gorge Region in Yunnan Province

The impact of highway construction upon surrounding ecosystems in the Longitudinal Range-Gorge Region of Southwestern China was detected based on field survey and experimental analysis. We conducted a study on Dali (from Dali City to Lijiang City) provincial road, Dabao (from Dali City to Baoshan City) highway and Baolong (from Baoshan City to Longling County) highway in the Longitudinal Range-Gorge Region to detect the effect of highway construction on surrounding soil quality using the method of space-for-time substitution, and predicted remediation of surrounding soil quality. The results showed that: (1) The effect of highway construction on both natural and cultivated soil quality is significant, and the effect is more significant in the period of highway construction than the period of highway in use. (2) The effects of highway construction is more apparent on downslope than upslope, and effect range was 200 m on downslope, while 150 m on upslope. (3) Soil remediation is mainly related to effect extent of highway construction, highway service time, vegetation restoration, soil organic matter and soil total nitrogen, among which, highway construction is the most important factor. (4) When vegetation coverage can be restored to 30% of the original condition, soil quality can be remedied to 44% of the original condition after 10 years, indicating that soil fertility remediation is rather difficult once it is destroyed.