Growth and yield responses of tomato to irrigation in screenhouse-potted soil amended with varying levels of poultry manure

The need for production of high value crops has increased over the years, hence the need to more appropriately determine irrigation water levels in water-scarce scenarios. The Aim of this research was to 1) determine the effect of deficit irrigation on growth and yield of tomato, and 2) determine how poultry manure amendments of soil would interact with irrigation to influence the observed growth and yield responses. There were two irrigation levels namely 0.75 and 1.5 l per plant per week, combined with 0, 34 and 68 g/plant poultry manure, in a 2 x 3 factorial design with three replicates. Growth and yield parameters were measured till maturity. Data were analysed through RTANOVA in a GLM at α=0.05. Results showed that the combination of 0.75 l irrigation water per plant per week with 34 g poultry manure per plant significantly increased number of leaves, branches and collar diameter.  At low levels of irrigation (0.75 l/plant/week) the highest number of flowers (196) is produced under fertilization with 68 g poultry manure per plant, with a reproductive success rate of 18.37%. When the irrigation rate doubles, the highest number of flowers (126 /plant) is produced in plants fertilized with 34 g/plant poultry manure, with a reproductive success rate of 42.06%., representing the best combination of treatments for maximum fruit yield; doubling manure rates to 68 g/plant results in increased flower abortion and reduced reproductive success.