An appropriate combination of inorganic and organic nitrogen sources and plant spacing is vital to increase the yield of tomato with minimum environmental hazards. We therefore carried out this experiment at the Crop Farm, Faculty of Agriculture, Eastern University, Sri Lanka to investigate the effects of different levels of organic nitrogen (ON) and inorganic nitrogen (IN) sources and plant spacing on growth and yield of tomato (Lycopersicon esculentum Mill.). Plants were grown at three different spacing (S1- 80 cm × 35 cm, S2- 80 cm × 50 cm and S3- 80 cm × 80 cm) and at three different levels of nitrogen sources (N1- 75% of IN + 25% of ON, N2- 50% of IN +50% of ON and N3- 25% of IN +75% of ON). The results showed significant variations on plant height, leaf area and plant biomass at harvesting time and fruit yield of tomato among treatments. Treatment N1S3 produced highest leaf area (1450.78 cm2 /plant). However, N1S1 produced highest plant biomass (2648.70 kg.ha-1) and fruit yield (27.93 Mt.ha-1). This study therefore suggests that combination of 75% of IN and 25% of ON and plant spacing of 80 cm × 35 cm is most favoured option to increase the productivity of tomato in Batticaloa region.

Keywords: Biomass, Nitrogen sources, Plant spacing, Sandy regosol, Tomato yield