Indian Journal of Dryland Agricultural Research and Development

Rainwater is the key input in dryland agriculture. The success to dryland agriculture lies in the efficient use of natural resources, particularly rainwater management. In a tropical country such as India which experiences more variation on rainfall, both in space and time, rain water management assumes vital importance in cutting down risks and optimizing crop production in dryland. Climate and soil are the two dominant factors in deciding whether or not runoff farming/water harvesting system will be possible and sensible. The hyper arid zone (P/PET < 0.03) is too dry for viable runoff farming, while sub humid zone (P/PET = 0.5 – 0.75) will be too wet. The runoff farming zone is primarily situated in the arid zone (P/PET= 0.03–0.2) and to some extent in the semi arid zone (P/PET = 0.2 – 0.5). Bellary region is characterized as one of the semi-arid zones of Karnataka bearing only 500 mm of average annual rainfall, confined in 35 rainy days having potential of runoff producing rain storms (5–7 days.) The study shows that the region experienced 13 meteorological droughts in the past 50 years in terms of annual rainfall. The region receives rainfall mostly from northeast monsoon and the crops are grown with conserved moisture during post rainy season (September - November). The seasonal rainfall analysis indicates the occurrence of agricultural droughts in 25 years in the past 50 years, which include 11 severe droughts. The average rainfall distribution shows that there is total failure in kharif season. However, some assured rainfall received during September and October has better prospect for rabi season. An attempt is made in this paper to analyze probability of rainfall, drought studies on various parameters and water budgeting studies etc. for designing of water harvesting system and crop planning. The findings of this study will help to plan the watershed management project in this region and similar agro climatic regions of Karnataka and A.P.