1. National Engineering Lab. for Efficient Utilization of Soil and Fertilizer Resources and National Engineering & Technology Research Center for Slow and Controlled Release Fertilizers; College of Resources and Environment, Shandong Agricultural Univ.; Taian Shandong 271018 China
2. Dep. of Soil and Water Sciences; Tropical Research and Education Center, IFAS, Univ. of Florida; Homestead FL 33031 USA
3. Agricultural and Biological Engineering; Institute of Food and Agricultural Sciences, Univ. of Florida; Gainesville FL 32611 USA
4. Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang Provincial Key Lab. of Agricultural Resources and Environment, Zhejiang Univ.; Hangzhou 310058 China
5. Coastal Plains Soil; Water and Plant Research Center, USDA-ARS; Florence SC 29501 USA
6. State Key Lab, of Nutrition Resources Integrated Utilization; Kingenta Ecological Engineering Group Company; Linshu Shandong 276700 China
7. Key Lab. of Humic Acid Fertilizer of Ministry of Agriculture; Shandong Agricultural Univ. Fertilizer Technology Company; Feicheng Shandong 271600 China