The 8^th Dr. B.V. Mehta Memorial Lecture^†

Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute, New Delhi, 110012.

^†Delivered on 18^th December, 2004 at the Central Arid Zone Research Institute (CAZRI), Jodhpur, Rajasthan, India and organized by the Jodhpur Chapter of the Indian Society of Soil Science