1. Key Lab. of Crop Nutrition and Fertilization; Ministry of Agriculture of China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences; Beijing China 100081
2. College of Resource and Environment, Northwest Sci-Tech Univ. of Agriculture and Forestry; Yangling Shaanxi China 712100
3. Institute of Plant Nutrition and Agricultural Resources, Henan Academy of Agricultural Sciences; Zhengzhou Henan China 450002
4. USDA-ARS, Water Management Research; Parlier CA 93648-9757