Jenny C. Calabio, Maria Luisa Z. Albacete, Esperanza P. Armada and Crisanto S. Lopez, Jr.
The efficient utilization of essential rice nutrients, particularly nitrogen, depends on the availability of water. Field experiments were conducted in farmers’ fields in Pototan, lloilo, for two dry seasons, to evaluate the best location-specific fertilizer management strategy suited for irrigated lowland rice under different water regimes. The verification trials were conducted in irrigated rice fields in 2002-2003 dry season at barangays Cahaguikican and /gang, both in Pototan town Province of Iloilo. In 2003-2004 dry season, the test was only conducted in Igang, Pototan. The treatments were laid out in a Randomized Complete Block (RCB) design with four replications using a plot size of 30 square meters. Treatments were tested as to (a) farmer’s actual practice, (b) growth stage-based N application (120 kg N/ha, 40 kg P,OJha, and 40 kg K,Olha), (c) leaf color chart (LCC) – based N application. Results in Cahaguikican, Pototan showed that the LCC-based nitrogen application is suited for the site. In /gang, Pototan, the farmer’s fertilizer management practice is cost-efficient under continuously flooded condition. However, if irrigation is done once a week, the LCC-based nitrogen application of fertilizer is recommended.