Agroclimatic Characterization of APRLP-ICRISAT Nucleus Watersheds in Nalgonda, Mahabubnagar and Kurnool Districts :Global Theme on Agroecosystems Report no. 30 uri icon

abstract

  • Knowledge on agroclimatology of a region is a valuable tool in crop planning. Agroclimatic analysis of the APRLP nucleus watersheds in three target districts (Nalgonda, Mahabubnagar and Kurnool) has been carried out on the basis of agromet data for the period 1971?2003. During the southwest monsoon season, more than 1000 mm rainfall was received at Nemmikal and Appayapally, while it was as low as 143 mm at Nandavaram. More than 85% of the annual rainy days occur during the five-month period ? June to October. Though all the locations have a semi-arid type of climate, there is a tendency for the climate to temporarily shift towards the drier side. About 45% of the study period now shows an arid type of climate. Among the watersheds, Malleboinpally has the most stable climate with 85% of the total years in its normal semi-arid climate. At Nemmikal, there appears to be a slight trend towards dryness in the past 25 years, after 1978, as the climate was never the dry sub-humid type, and it has slowly been tending towards the arid type. Analysis of water balances in extreme rainfall years indicated that many locations recorded water surplus even in dry years. Between the wet and dry years, variation in the water surplus is much higher compared to the water deficit. Nemmikal (medium-deep Vertisol) and Nandavaram (deep Vertisol) watersheds provide greater opportunity for double cropping. Appayapally, Thirumalapuram and parts of Nemmikal watersheds with medium-deep Alfisols, provide opportunity for double cropping with relatively short duration crops, but are more suitable for intercropping with medium-duration crops such as pigeonpea and castor. Watersheds in Kacharam, Mentapally, Sripuram, Malleboinpally and Karivemula have medium-deep Alfisols and provide greater potential for sole cropping during rainy season with crops of 120?130 days duration, and intercropping with short to medium-duration crops to make better use of soil water availability. Early season drought occurs at Karivemula and Thirumalapuram and early and mid-season droughts occur at Nandavaram. These sites would require crop/varieties tolerant to early or mid-season droughts depending upon the location.It is also observed that Mentapally, Malleboinpally, Nemmikal and Appayapally have greater potential for water harvesting. Assured rainfed crop-growing season is about 165 to 175 days for the Vertisols areas and about 130 to 150 days for the Alfisols areas. There is variation in both the beginning and ending of the season; however, the end is more variable compared to the start. No definite relationship exists between the beginning and length of the growing season

publication date

  • 2006