WATER USE PATTERN AND WATER PRODUCTIVITY OF SWAMP TARO IN TUBE-WELL COMMANDS

Abstract

Results reveled that reference crop evapotranspiration (ETc) for swamp taro was 955.9 mm in 267 days. At early growth period daily water demand was low (1.95mm) and it increased to 5.2 mm during March-May and thereafter demand for water decreased in wet period. Total field water supply (FWS) was 1977 to 2196 mm irrigation during non rainy days and 946.6 to 1216.8 mm rainfall over the total crop period during 2000 and 2001. Periodical FWS was like that for puddling operation 156-225 mm, rooting period (20 days) 75-100 mm, formative period (60 days) 838-850 mm, stolon production period (March-May) 1027-1158 mm. Total number of irrigation was 52-56 and the depth of irrigation varied from 25mm at early stage to 58 mm at peak summer period and irrigation was given at 3-5 days interval depending upon atmospheric demand. Crop growth was very much influenced by the crop age. Stolon production gradually increased from March to June. Total stolon production was 30.91 t ha-1 with an economic return of Rs. 78.7 thousands. The water productivity(WP) of swamp taro was 0.97 kgm-3 in physical term and Rs 2.48 m-3 in economic term.