1. School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU, U.K., Department of Soil Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh, Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, U.K., Department of Soil, Water & Environment, University of Dhaka, Dhaka 1000, Bangladesh, and Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China