Tropical Africa escaped from the glaciers that covered the temperate parts of the world during the Ice Age. The legacy is that most of the parent materials of the soils of tropical Africa are old, highly weathered and devoid of bases and phosphate-bearing minerals. Traditional farming systems which were relatively stable and sustainable relied on long fallow periods after one to two years of cropping to maintain the productive capacity of the soils. In recent times and especially in densely populated areas, a sizeable class of 'landless' farmers have begun to cultivate marginal lands or to invade the 'forest reserves' thereby exacerbating the problems of land and environ mental degradation. of soil fertility that will facilitate the production of adequate quantities of the principle Maintaining a level staples has become a major challenge to agricultural scientists in tropical Africa. To increase the nutrient supplying power of soils requires the inputs of fertilizers. These can be organic or inorganic. The efficiency with which these externally supplied inputs can increase agricultural production and reduce soil and environmental deterioration is dependent on the ability of scientists to determine the right types and quantities of the products to apply to each soil, crop and cropping system as well as the ability of farmers to acquire requisite farm manage ment skills.

This book presents systematic scientific appraisal, classification, genesis and viable technologies for reclamation and management of salt-affected soils and marginal quality waters across India and several other countries. Nature, solubility and geo-chemical mobility of salts have been provided as basis for the development of alkali and saline soils and groundwaters under specific agro-hydro-ecological regions. Chemical amendment (gypsum) based reclamation technology of alkali soils and related pre and post-reclamation water, nutrient and crop management interventions, including re-sodification issues have been comprehensively addressed. Features and operational guidelines of surface, subsurface, vertical and bio-drainage systems have been thoroughly discussed; likewise, amelioration of irrigation induced saline soils in inland and coastal regions and preventive measures for control of salinity and waterlogging along with environmental trade-offs. Practical approaches for amelioration and judicious use of saline, alkali, high SAR- saline and waste waters have been synthesized for different cropping and agro- forestry systems. Emerging issues on use of industrial by-products as amendments for alkali soils, physiological aspects of salt resistance, anatomical and biochemical mechanism of submergence tolerance, specific ion effects of poor quality waters, crop diversification, groundwater recharge, rejuvenation of tsunami affected coastal soils, safety against occurrence of poisonous gas in tube well pits, paddy straw burning and others have been adequately deliberated upon. Combining scientific principles with field experiences, the book is expected to serve as a useful knowledge base for research workers, teachers and students of soil science, agronomy, plant breeding, forestry, irrigation engineering, extension workers, environmentalists and planners associated with reclamation and management of salt affected soils and waters on sustainable basis in developing and developed countries.

Can a continuous growth of agriculture be achieved in the sub-Sahara region without inducing irreversible damage to the ecosystem? Until now, doubts have been expressed as to the actual capacity of the soils to sustain a desirable increase of production which can match the requirements of a fast-growing population. Thirty years of investigation and a renewed comprehensive interpretation of research data on soil fertility show that a sustainable agriculture growth could be a practical possibility in a savannah region.

This book provides a synthesis of current agricultural research in Africa with the aim of presenting evidence based information that can be directly applied into improving the African smallholder farmers’ food security. It presents positive scientific research that has been undertaken in Africa, in simpler terms, thus driving the research for development agenda contributing to the attainment of SDG 2. Numerous research that targets resource poor African smallholder farmers has been published, yet the region faces very low productivity levels. This lack of translation from research to food security and increased agricultural incomes is due to the poor uptake of scientific research by farmers, which is partly due to poor presentation of this body of knowledge into simpler forms that extension workers and farmers can directly adopt. Therefore, this book offers research information in an easy, digestible and application oriented style, so as to enable transformation of the African agricultural sector by effectively driving agricultural productivity in Africa. This book is of interest to African extension workers, who will translate the simplified knowledge into lessons that can be useful to smallholder farmers. The book is also beneficial for policy makers as well as academics, researchers and other science based professionals.

Food insecurity is a fundamental challenge to human welfare and economic growth in Africa. Low agricultural production leads to low incomes, poor nutrition, vulnerability to risk and threat and lack of empowerment. This book offers a comprehensive synthesis of agricultural research and development experiences from sub-Saharan Africa. The text highlights practical lessons from the sub-Saharan Africa region.