Assessment of climatic risk and coping techniques in two major corn production areas [Isabela and Bukidnon, Philippines]

Climate is one of the most important factors in field crop production and management. Directly and indirectly, it affects crop growth and development. Different crop physiological processes are highly influenced by climate. Build-up, spread, and the biological cycles of different crop pests and diseases, which are determinants of crop survival and productivity, are also climate-related. Climate variability (El Niño and La Niña) and climatic extremes (typhoon, drought, etc.) are major sources of climate risk in crop production resulting in variable yield and possible yield losses. In consideration of all these concerns, Lansigan (UPLB) [University of the Philippines Los Baños, College, Laguna, Philippines] conducted from April 2008 to June 2009 a study to determine the optimal planting period in two major corn growing areas - Isabela and Bukidnon [Philippines], considering climate variability. The optimum or best planting date would be the date that will give the highest possible yield with the lowest possible variance. The study used the eco-physiological or process-based crop simulation model (CERES-Maize model) to determine corn yields given the observed as well as synthetic weather data obtained using a weather data generator (SIMMETEO) for the specified climate scenarios. The crop model is parametized using the crop genetic coefficients for IPB 911 corn variety. Corn yields and crop yield probabilities under normal year (average year), dry year (El Niño year), and wet year (La Niña year) were determined for the two provinces. Simulation results showed that corn yield during wet and dry years in Isabela vary significantly. In Bukidnon, however, the differences and variability in yields were not distinct since the effects of El Niño in the province were not serious. The optimum planting date for each of the site during normal, El Niño, and La Niña year was determined using the mean variance analysis.