Establishing the Planting Calendar for Onions (Allium cepa L) Using Localized Data on Temperature and Rainfall

Abstract

The study aimed to determine a planting calendar for a red variety of onion (Allium cepa L) in Aritao, Nueva Vizcaya utilizing the temperature and rainfall data of the locality and matched with the temperature and water requirements of the onion plant. Onion has 9 stages starting from the sowing stage to the fall-down stage that lasted for an average of 126 days. Onions require cooler weather during the early stages of growth while a dry atmosphere with moderately high temperature is necessary for bulb development up to maturation until the harvesting period. Water requirements of the onion plant also vary from every stage; lack of water, as well as excessive water, could be disadvantageous to the plant growth and development. Ten years of data on rainfall and temperature of the locality were sourced-out in the NVSU Agromet station. These data were used to forecast 12 months of data on temperature and rainfall using three forecasting methods of the SPSS, NCSS, and MS Excel. The forecasted rainfall and temperature data on weekly basis were matched to the 9 stages of onions to its temperature and water requirements starting from the sowing stage to the fall-down stage. The study was able to determine the best timing for the plant; it is on the second week of February up to the third week of June. Onions planted at this time interval have a high forecasted percentage of survival as the temperature and water requirements of the plant in its stages were all sustained.