An Interview with Prof. Dr. Rattan Lal “You cannot continue taking money out from the bank without putting it back. So improvement of soil on the basis of what has been taken out from harvesting must be replaced in a scientific manner,” stressed Prof. Dr. Rattan Lal, a distinguished university professor in soil physics and tropical soils from Ohio State University. Either chemically or organically “Applying manure or using bio-soil is the best option, but sometimes it is not strategically a very good option because manure requires a bulk amount. We require 10 ton/hectare of manure, which is the equivalent to100 kg of chemical fertilizer. So sometimes it is a question of logistics” he added. “A judicious combination of both organic and inorganic fertilizers is required because many times the organic matter is not adequate – it is called integrated nutrient management.” Sub Saharan soils are marginalized “I think Africa is the continent where the green revolution has by-passed because the soils in Sub Saharan Africa are really marginalized. They are depleted, denuded and degraded. Soil erosion and nutrient depletion of soil organic matter content have been very serious problems in Sub Saharan Africa. For sustainability, soil quality must be improved,” he concluded.