Determination of Optimal Water Requirement for Sweet Corn Crop Based on Meteorological Data and Plant Growth Parameters

Maize (Zea mays L.), or corn, is the world’s leading cereal crop and ranks third in importance after rice and wheat. It is a primary food source for humans and livestock and a raw material in various industries. To reduce dependence on corn imports, Malaysia has initiated large-scale local cultivation. However, the maize industry faces challenges from waterlogging and water scarcity due to the tropical climate, which causes droughts and floods, impacting maize production. This study aims to improve crop water requirement (CWR) estimations for maize using CROPWAT, considering growth stages and soil variability, and validate irrigation management strategies. Based on 30 years of climatic data from MetMalaysia, evapotranspiration (ETc) was estimated using CROPWAT V8. Experimental plots with four irrigation water application (IWA) treatments were used to validate ETc: T1 (50% ETc), T2 (75% ETc), T3 (100% ETc), and T4 (125% ETc). Crop growth parameters were assessed at four growth stages: plant height, stem diameter, shoot fresh weight, and kernel moisture. Results showed T4 (451.07 mm/season) had the highest growth rate and met all hybrid corn growth standards set by the Department of Agriculture, Ministry of Agricultural and Food Security (MAFS). In contrast, T3 (100% ETc) was insufficient for sweet corn, failing to meet several standards. Thus, T4 (125% ETc) proved the most effective IWA practice, particularly for areas within a 30 km radius of the Subang weather station.