B. B. Basak, Sharmistha Pal and S. C. Datta* Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute, New Delhi 110 012, India Present address: Directorate of Medicinal and Aromatic Plant Research, Boriavi, Anand 387 310, India Present address: Central Soil and Water Conservation Research and Training Institute, Research Centre, Madhya Marg, Chandigarh 160 01...