Alagha S.A and Sangodoyin A.Y
Abstract
Accurate determination of irrigation schedule is a very difficult and time consuming process. Most advanced countries with advanced agricultural systems have developed data bank from which irrigation schedules for various field crops at various vegetative stages and soil types are provided. In Nigeria, irrigation schedule has always being left at the mercies of estimation from various known methods of determining water demand or water use of a crop from various climatological and hydrological data around the production area. This is a different ball game all together when planting on soilless media like sawdust, coconut fiber, peat moss, sand and others as recently practiced in many advanced countries like Japan instead of planting directly on the soil which in turns communicates directly with the earth mass. Since irrigation schedule depends majorly on type of crop, soil or soilless medium and climate, it is reasonable to provide data and other means of determining the irrigation of some crops grown on some locally available soilless media from the existing methods of irrigation scheduling. In this study, the information adapted from FAO (1998) was modified to obtain a set of steps used to determine the irrigation schedule for tomato grown on some soilless media in Owo, Ondo state, south west of Nigeria. Tomato was irrigated with sprinkler and drip irrigation systems and water use by tomato was monitored at the various growth stages. The irrigation water need of tomato was 715mm/month while irrigation interval and numbers of application were 5days and 24 respectively for the peak season of water demand. As the soilless media will often drain away, several numbers of application of water at very small quantities were administered per day based on the calculated irrigation schedule. Volume of water/plant/day was 0.44l/plant/day. This value was adjusted for the early season and late season of tomato based on type of soilless media and daily water consumptive use. The irrigation schedule resulted in optimum performance of tomato with good quality yield and marketable tomato fruits under both irrigation systems.