Current potassium-management status and grain-yield response of Chinese maize to potassium application. - Wu, Liang-quan; Ma, Wen-qi; Zhang, Chao-chun; Wu, Liang; Zhang, Wei-feng; Jiang, Rong-feng; Zhang, Fu-suo; Cui, Zhen-ling; Chen, Xin-ping (Journal of Plant Nutrition & Soil Science, 2013)