Effect of Different Organic Fertilizer Application Rates on Yield and Yield Attributes of Tomato (Lycopersicon esculentum)

A field experiment was conducted at the Botswana University of Agriculture and Natural Resources (BUAN) to investigate the effects of organic fertilizer on growth and yield tomato from October 2014 to March 2015. The experiment was laid out in a randomised complete block design (RCBD) with four treatments being varying levels of organic fertilizer; 0 kg m-2, 5 kg m-2, 7.5 kg m-2 and 10 kg m-2 each replicated three times. The yield attributes measured were plant height, stem thickness, canopy diameter, number of leaves, fruits and fruit weight. Organic fertilizer application rates of 7.5 and 10 kg m−2 revealed significantly (p<0.05) taller plants compared to other treatments. A highly significant difference in plant canopy was observed across the four fertilizer application rates. Higher fertilizer application rate of 10 kg m-2outperformed the rest of the treatments. A highly significant treatment effect was observed on leaf number of plants in the 10 kg m-2 application rate. The same trend was observed for stem thickness with the 10 kg m−2 application rate. A linear relationship (R2 = 0.9655) between number of fruits and fruits weight was revealed. Number of fruits and fruits weight increased with increasing organic fertilizer application rates. The 10 kg m-2 fertilizer application rate outperformed the rates for most measured parameters. Results of the study demonstrate that the use of organic fertilizer would help small-scale vegetable growers to maintain the long-term soil productivity for sustainable tomato cultivation since it is affordable and abundant in Botswana.