DefinePK

Abstract

The aim of this study was to evaluate the effect of Chlorpyrifos application in tomato on soil nitrogen, organic matter, pH and bacterial population. The study was conducted between 2016 and 2018 at Makerere University Agricultural Research Institute at Kabanyolo in Wakiso district in central Uganda, East Africa. The findings of the research would be useful in informing policy makers of Uganda about the importance of proper application of pesticides and conservation of biodiversity, specifically bacteria so as to improve soil fertility. Soil samples were collected at 0 to 15 cm depth and analyzed to determine nitrogen, organic matter, pH and soil bacteria counts. Randomized Complete Block Design (RCBD) was used with three replications. Nitrogen was determined using Kjeldahl method, organic matter was evaluated by wet-acid oxidation, pH was measured by pH meter and bacterial population was determined by plate count technique. Results showed that Chlorpyrifos treated plots had nitrogen content varying from 0.18 % to 0.2 %. Organic matter content was 3.3 % in Chlorpyrifos treated plots, pH was between 6.0 to 6.8 in all three seasons 1, 3, 4 except season 2 with pH of 6.9. Bacterial count increased from 5.0x10⁸ cfu/g in season 1 to 10.0x10⁸cfu/g in season 2. Chlorpyrifos reduced bacterial population in all three seasons except season 2. Chlorpyrifos application in tomato had no effect on nitrogen, it increased organic matter to 3.5 %, pH was slightly acidic, (pH 6.0 to 6.5) and reduced bacterial population from 4.8x108cfu/g to 4.2x108cfu/g