Genesis and Management of Sodic (Alkali) Soils

Book excerpt: Land and water, the two crucial natural resources for agriculture, are decreasing as a result of burgeoning population of the country. At the same time, various forms of degradation are taking a toll on the productivity of these resources so much so that large areas have been taken out of plough. Current assessment reveal that already 6.73 million ha area has gone out of cultivation because of excessive salts or high sodicity and this area is likely to expand to 20 million ha by 2050 because of the faulty irrigation and drainage water management practices being adopted in irrigation commands. Of the current affected area, more than 50% is sodic in nature, which requires some kind of chemical amendment for reclamation. While our knowledge and understanding of the causes, nature and harmful effects of sodic soils have tremendously increased, availability of gypsum on account of environmental problems on its mining has caused concerns. Apparently, there is a need to push for other amendments especially the industrial wastes and publish the information in practical terms for various stakeholders. This book is an attempt in this direction. Taking into account the widely varying needs of the clients, the chapters of this book have been organized to include history, origin and genesis of sodic lands, basic principles of diagnosis, nature and properties of sodic lands, amendments, reclamation package and alternate land management. Since sodic water irrigation is one of the factors in the formation of sodic lands, a separate chapter deals with this issue highlighting the extent and distribution, chemical characteristic and management options for the use of sodic water. The economic analysis procedures and socio-economic issues of sodic land reclamation are included in a separate chapter with appropriate case studies. Since latest scientific information on new technologies with case studies is included, we believe that this book is an improvement over the existing books and is a useful addition to the literature on this subject. In our view the information contained in this book would be handy to field practitioners in the Government Departments and NGOs to plan and undertake large sodic land reclamation projects. Since the basic principles and practices have been very well elucidated, the book can be used as a text book in agricultural and engineering colleges. It can also be used as a source material in training programs being organized by various scientific organizations. We believe that the book would prove to be a handy reference resource to all those interested in sustainable irrigated agriculture for the food and nutritional security of the nation.