AGRO-CLIMATIC ANALYSIS FOR IRRIGATION WATER MANAGEMENT OF ANDHRA PRADESH

Abstract

Agro-climatic characterization of AP for dry land Cultivation was performed using Rainfall and Potential Evapotraspiration indices in a GIS environment. Based on the total quantity and distribution of rainfall, irrigation, soil types and cropping patterns the state of AP is broadly divided into 22 agro-climatic zones. Using the criteria of Moisture Adequacy Index (MAI), AP, in general is classified as moderately moisture deficit semi and state. Moisture Adequacy Index (MAI) as suggested by Hargreaves (1971) using Precipitation and Potential Evapo Transpiration (PET) was used to delineate the climatic variability over AP. Weather data from the new LocClim of FAO was used to develop the Moisture Adequacy Index for States of AP. Contours were plotted on the map of AP using ArcGIS software. The contours thus developed indicated that most of the stations were falling under the class/category of moderately deficit moisture (0.34 — 0.67). Pockets of high variability in the districts of Vizainagaram, west Godavari, Nizamabad, Srikakulam and Adilabad were observed. Sites of the pockets of very high MAI variability were identified through Google Earth and found that they were rich in water bodies and vegetation. Thus the pockets of intense MAI variability could be attributable to the presence of water bodies like minor irrigation tanks and reservoirs (small and large) in the context of AP.The small irrigation tanks frequently distributed in the district affected the variability pattern in Moisture Adequacy Index of a given location. The AP in general classified as semi and tropic zone. In order to make available the water to different sectors viz, agriculture, drinking, industry etc a large number of major and minor reservoirs are constructed. Since the staple food of people in AP is rice, whenever and wherever farmers get irrigation water opt for cultivation of rice. The spread of rice field in the state is also viewed as affecting the micro climatic condition in the state. Identification of this micro level variability is difficult to see with routine data being collected in different observatories. agro climatic zones classified for different crops in different (Kharif and Rabi) seasons were classified based on crop productivity of AP. Keywords: Agro-climatic zoning, Climate, Precipitation, GIS, Evaptransiration, Moisture Adequacy Index (MAI), Crop Productivity, crop suitability Agro-Climatic Zoning.