1. State Key Lab. of Plant Physiology and Biochemistry; Key Lab. of Crop Cultivation and Farming System; China Agricultural Univ.; Beijing 100193 China
2. Ministry of Agriculture Key Lab. of Plant Nutrition and Fertilizer; Institute of Agricultural Resources and Regional Planning; Chinese Academy of Agricultural Sciences; Beijing 100081 China
3. Dep. of Soil Science; Faculty of Agriculture; Univ. of Calabar; Calabar 540213 Nigeria
4. Cotton Research Center; Shandong Academy of Agricultural Sciences; Jinan 250000 China