Combined effects of climate, restoration measures and slope position in change in soil chemical properties and nutrient loss across lands affected by the Wenchuan Earthquake in China

摘要

The MS 8.0Wenchuan Earthquake in 2008 caused huge damage to land cover in the northwest of China's Sichuan province. In order to determine the nutrient loss and short term characteristics of change in soil chemical properties, we established an experiment with three treatments (‘undestroyed’，'destroyed and treated', and 'destroyed and untreated'), two climate types (semi-arid hot climate and subtropical monsoon climate), and three slope positions (upslope, mid-slope, and bottom-slope) in 2011. Ten soil properties-including pH, organic carbon, total nitrogen, total phosphorus, total potassium, Ca~(2+), Mg~(2+), alkaline hydrolysable nitrogen, available phosphorus, and available potassium-were measured in surface soil samples in December 2014. Analyses were performed to compare the characteristics of 3-year change in soil chemical properties in two climate zones. This study revealed that soil organic carbon, total nitrogen, Ca~(2+) content, alkaline hydrolysable nitrogen, available phosphorus, and available potassium were significantly higher in subtropical monsoon climate zones than in semi-arid hot climate zones. However, subtropical monsoon climate zones had a higher decrease in soil organic carbon, total nitrogen, total phosphorus, total potassium, and alkaline hydrolysable nitrogen in 'destroyed and untreated* sites than in semi-arid hot climate zones. Most soil chemical properties exhibited significant interactions, indicating that they may degrade or develop concomitantly. 'Destroyed and treated* sites in both climate types had lower C:P and N:P ratios than 'destroyed and untreated* sites. Principal component analysis (PCA)