Agroclimatic Characterization of SUJALA-ICRISAT Watersheds in Karnataka

1. Agroclimatic Characterization of SUJALA-ICRISAT Watersheds in Karnataka AVR Kesava Rao, SP Wani, Piara Singh, K Krishnappa and BK Rajashekhara Rao Importance of Agroclimatology Watershed locations Anchatgeri, Dharwad • Scientific crop planning is possible through an understanding of agroclimatic potential • Climate characterization helps to Identify management practices to take advantage of the favourable weather conditions • Risks due to adverse weather conditions can be minimized through climatic information • Long period weather data is analyzed to characterize agroclimate of the watersheds • Annual PET is 1594 mm • Annual average rainfall is 697 mm • Annual probability rainfall is 273 mm • Rain>PET is in two periods • Seasonal rainfall is 549 and PET is 659 mm • Water harvesting 1st half of October • Moisture stress in 1st half of Sep • Seasonal IMA is 79% Huthur, Kolar • Annual PET is 1638 mm • Annual average rainfall is 711 mm • Annual probability rainfall is 180 mm • Rain>PET is in mid-Sep to Oct • Seasonal rainfall is 549 and PET is 740 mm • Water harvesting 2nd half of Sep • Moisture stress in 1st week of Sep • Seasonal IMA is 71% Kanakapura, Tumkur • Annual PET is 1937 mm • Annual average rainfall is 543 mm • Annual probability rainfall is 66 mm • Rain>PET is in mid-Sep • Seasonal rainfall is 429 and PET is 918 mm • Seasonal IMA is only 47% Methods Summary • Potential evapotranspiration (PET) estimated by FAO-Penman-Monteith method • Water balances computed by Thornthwaite and Mather method • LGP, dry and wet spells calculated based on Index of Moisture Adequacy (IMA). • Analysis indicated wide variation in the agroclimatic potential across the watersheds • In Dharwad and Haveri districts, bimodal rainfall distribution is observed • Dharwad and Haveri districts have good potential for runoff water harvesting and structures while, Chitradurga, Kolar and Tumkur have relatively lower water harvesting potential • Kanakapura has little scope for water harvesting. Only 47% of crop water requirements are met by rainfall as indicated by seasonal IMA, crops often experience moisture stress and in situ moisture conservation measures play a greater role • There is more variation in the beginning of growing period compared to the end. At Hubli and Haveri, it is as early as 10 Jun; as late as 20 Aug at Kanakapura. • Extends up to 20 Dec at Gudibanda and Sidlaghatta; Ends by 25 Nov at Kanakapura • Hiriyur has great risk of dry conditions during crop vegetative phase Variability in the length of growing period (LGP) at watersheds International Crops Research Institute for the Semi-Arid Tropics, Patancheru, 502 324, Andhra Pradesh