1. College of Resources and Environment/Key Laboratory of Eco-Environments in Three Gorges Region (Ministry of Education), Southwest University, Chongqing 400715, China
2. Key Laboratory of Arable Land Conservation (Southwestern China), Ministry of Agriculture, Chongqing 400715, China
3. State Cultivation Base of Eco-Agriculture for Southwest Mountainous Land, Southwest University, Chongqing 400715, China