国家高技术研究发展计划项目No.2013AA06A206;中国科学院地理科学与资源研究所优秀青年人才基金项目No.2012RC203;国家自然科学基金项目No.41271339;中国公益性行业农业科研专项No.201403015Supported by the National High Technology Research and Development Program of China No.2013AA06A206, the Science Foundation for the Excellent Young Talents of Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science CAS No.2012RC203, the National Natural Science Foundation of China No.41271339 and the Special Fund for Agro-scientific Research in the Public Interest No.201403015