Department of Scienttfic Research;
Sichuan Normal University;
Chengdu 610068;
P. R. China;
College of Chemistry and Materials Science;
Sichuan Normal University;
Chengdu 610068;
P. R. China;
Engineering Research Center for the Development of Farmland Ecosystem Service Functions;
Sichuan Province Institutions of Higher Education;
Chengdu 610068;
P. R. China;