Abstract

Studies were conducted in 2007/2008 cropping seasons under a tropical greenhouse (GH) and open field (OF) of the National Horticultural Research Institute (NIHORT) experimental farm. Seeds were sown into the nursery in October, 2007 and January, 2008 for the GH and OF after soil sterilization. Soil samples were analyzed for micro and macro nutrients. Organic manure: Poultry (PM) and horse (HM) wastes and irrigation water were also analyzed using standard laboratory procedures. Drip irrigation and fertilization structures were installed into the GH and OF in 2007 and 2008, respectively. Five week old tomato seedlings were transplanted into the GH in December, 2007 and OF in February, 2008. Organic manure in solution (OMS) was prepared at the rate of 4.2 KgL^-1 and NPK at 0.6 kgL^-1. Three levels of drip irrigation consisting of water and three levels of fertigation with two separate tanks containing mineral fertilizer (NPK) and poultry manure were investigated for the GH with corresponding water, NPK and HM for OF. Applications were carried out once (W₁), twice (W₂) and thrice per week in both GH and OF conditions using split-plot arrangement fitted into randomized complete block design with three replicates. Plants under PM applied at W₂ gave the highest yield (7.4 ha^-1) with significantly higher lycopene formation. Vitamin C was however best under drip irrigation in the GH. B- Carotene was highest under HM for OF. Overall result showed that plants under PM+W₂ in the GH had better yield than others. Likewise, lycopene formation was significantly best under PM in the GH which suggests preference of GH tomato production over OF.

Key words: Greenhouse, open field condition, tomatoes, drip irrigation, fertigation.