Water Balance In The Bicol Region

Flaviana de Leon Hilario

The water balance was computed for four weather stations in the Bicol Region over a period of ten days or a decade. The parameters used were crop evapotranspiration, effective rainfall and change in soil water content. The Penman equation was used to get the potential evapotranspiration and by multiplying it by the appropriate crop coefficient, the crop evapotranspiration was computed. The relation between the average rainfall was used to get the effective rainfall. Computing the water balance for different growing periods for each station shows that in general, there is adequate water supply in the region. The optimum planting dates for rice production are December 1 for Legaspi and Virac, December 21 for Virac for the 2nd cropping and June 1 for Daet and Virac, July 1 for Legaspi for the 1st cropping. However, Masbate was found to be suitable for rice based on crop water requirement. Corn production is highly suitable in Masbate where 3 croppings are possible. The optimum planting date is anytime during the month of December and May 1. Other places in the Region can be planted with corn one or two times a year. The main problem in the Region are typhoons, rains for long duration of time, floods and lack of water, when and where it is needed.