1. College of Resources & Environment; Northwest A&F University; No. 3 Taicheng Road Yangling Shaanxi 712100 China
2. Shaanxi Land Construction Group; Xi'an Shaanxi 710075 China
3. Department of Soil Science and Soil Water Conservation; PirMehr Ali Shah Arid Agriculture University Rawalpindi; Rawalpindi 46300 Pakistan
4. Department of Soil Science; College of Food & Agriculture; King Saud University; POB 2460 Riyadh 11451 Saudi Arabia