Agronomic, Water Productivity and Economic Analysis of Irrigated Rice under Different Nitrogen and Water Management Methods
The most limiting factors for irrigated rice farming are water and nitrogen. Efficient water and nitrogen management has remained critical for sustainable rice production in irrigated rice farming system. Due to rapid global population growth and climate change, future rice production will depend heavily on developing strategies and practices that use water and nitrogen efficiently. The study therefore set to evaluate agronomic, water productivity and economic analysis of irrigated rice under various nitrogen and water management methods. To achieve the set objectives, field and pot experiments were carried out at the Soil and Irrigation Research Centre, University of Ghana, Kpong in 2015 and 2016 cropping season. The field experiment was laid in a split plot design with water management treatments as main plots and N fertilizer as subplot treatment. The pot experiment was carried out in a randomized complete block design with five replications. The water management treatments were; continuous submergence (SC), alternate wet and dry soil condition (AWD) and moist soil condition (MC). Nitrogen fertilizer rates were; no N fertilizer (N0), 60 kg N/ha (N1) and 90 kg N/ha (N2). Data such as yield and yield parameters of rice, water use, water productivity, costs and returns were recorded. Results obtained from both pot and field experiments revealed that rice yields were at par in AWD and SC but yields were lower in MC treatment. With N fertilizer, higher yields were observed with 90 kg N/ha. The interaction effect of submerged with 90 kg N/ha gave the highest grain yield. N fertilizer effect on water use and water productivity was ranked as N2 > N1 > N0 while water management effect on water use and water productivity was ranked in this order: SC > AWD > MC and MC > AWD > SC respectively.