国家科技支撑计划项目2014BAD11B03;国家测土配方施肥补贴资金项目财农[2009] 211号;恩施州科技计划项目XYJ2014000039资助 This work was supported by the National Science and Technology Support Plan2014BAD11B03;the National Project of Soil Testing and Fertilizer Recommendation Subsidies[2009] 211;the Science and Technology Plan of Enshi Autonomous PrefectureXYJ2014000039