Institute for Integrated Development of Agriculture;
Beijing Academy of Ago-forestry Sciences;
Beijing 100097;
P.R.China;
Institute of Resource;
Beijing Normal University;
Beijing;
100875;
P.R.China;
College of Agronomy and Biological Technology;
China Agricultural University;
Beijing 100094;
P.R China;
Institute of Geographial Sciences and Natural Resource Resarch;
CAS;
Beijing 100094;
P.R.China;