1. Soil Science Department, College of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia
2. Chromatographic Analysis Unit, Soil Science Department, College of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia
3. Faculty of Agriculture, Sultan Sharif Ali Islamic University, Sinaut Campus, Km 33, Jln Tutong, Kampong Sinaut, Tutong TB1741, Brunei
4. Department of Microbiology and Plant Pathology, University of California Riverside, Riverside, CA 92507, USA