Irrigation_in_India

INTRODUCTION Irrigation is an age-old practice and in fact as old as man's first attempt at crop growing. The beginning of agriculture revolutionised the way of living of primitive man who was till then dependent only on hunting and food gathering. Agriculture heralded the era. of development of human civilization. Early agriculture involving mainly food production changed slowly to modern agriculture through a continuous evolution of agricultural technologies. This transformation gave a strong structural and economic base to the human society for its existence and progress. Irrigation has dictated and decided largely the pace and the process of agricultural development. Human civilization grew up near natural water resources and there are many records of the practice of irrigation from rivers and from man-made canals, wells and tanks. Excavation of the ruins of Mohenjo-Daro of the Indus valley civilization that flourished and reached its peak in 3000 BC illustrates the existence of a network of well-designed water supply and drainage systems. The Egyptian dam on the Nile river to store water for drinking and irrigation is claimed to be 5000 years old. In many other countries like Japan, Syria, China, Java and Italy, there are references of ancient irrigation works, some of which are still in service and some others have been transformed and improved upon with advancement of technological knowledge. Climate, soil and water are three basic natural resources that decide the nature, scope and extent of successful crop growing. Climates decide the availability of water and the type of crops to be grown in a region, while soil serves as a storehouse of water and nutrients for plants. Water is vital for any life process and there can be no substitute for it. There is a heavy demand of water for industry, domestic work, sanitation and recreational activities, which largely affects the availability of water for agriculture. Inadequacies of rainfall in most places make irrigation water also more scarce. The effectiveness of rainfall, even in high rainfall areas, is again vitiated by its erratic occurrence and uneven distribution. Droughts alternating with floods in one or the other regions cause immense damage to crop production processes. The main concern productive agriculture is the effective and efficient supply of water to crop fields. The general inadequacy of irrigation water and growing demand for crop production including remunerative cropping in modern times need a systematic study of irrigation problems and methods of efficient and economic use of water. Since irrigation potential is created at a huge cost, it is necessary to derive maximum benefit from the created potential. Often, a gap exists between irrigation potential created and its utilization, and that makes the situation more serious. A large amount of water is wasted in conveyance and distribution systems where lining of canal, distributaries and water courses has either not been undertaken or has been ill-maintained. Improper irrigation scheduling, land grading and levelling and faulty method of irrigation lead to waste of water in crop land. Two situations may arise in deciding the course of water management. When the arable land is large as compared to water available for crop growing, the objective of efficient water management would be to maximize crop production per unit of water. On the other hand, when, the land is limited as compared to available water, the aim would be to maximize production per unit of land without wasting water.