AN EVALUATION OF ECONOMIC WATER PRODUCTIVITY AND WATER BALANCE OF DRY SEASON IRRIGATED RICE UNDER DIFFERENT IRRIGATION REGIMES IN NORTHERN GHANA

Abstract

The major limiting factor for irrigated rice cultivation is water. As the demand for effective management of water increase due to climate change, future rice production will depend heavily on developing and adopting strategies and practices that use efficient water application. The objectives were to evaluate effects of different irrigation regimes on crop and economic water productivities as well as water balance for dry season irrigated rice production. This was to enable rice farmers and irrigation management to make an informed decision on the most economic and efficient water use regime for rice production. Two experiments were conducted using a randomized complete block design with 4 replications at On-Station (SARI) and On-Farm (Bontanga Irrigation Scheme) in 2012/2013 and 2013/2014 dry seasons. The treatments were, surface irrigation with applied water equal to: the Field Capacity (FC) moisture content (W1); Saturated soil moisture content (SC) (W2); Continuous flooding (CF) up to 10 cm level, used as control (W3); 10ETc (W4) and 15ETc (W5). A 115 days rice variety, Gbewaa (Jasmine 85) was used for the experiments. Seedlings were transplanted at spacing of 20 cm × 20 cm and one seedling per stand in a 1 m2 microplots On-Station and 7 m 2 plots on-farm. Data was collected on plant growth parameters and grain yields from four (4) replications. The results showed that grain yield of the On-Station as well as the On-Farm experiments showed significant difference between Field capacity and the rest of the treatments at p=0.05 level of significance. FC gave the highest water productivity (0.311 kg/m3) while SC gave the highest value of Economic Water Productivity (0.084 $/m3). In terms of water use, it is more economic to produce rice under saturated culture in the Northern Region of Ghana.