ABSTRACT
This project produced and evaluated a Self-propelled boom sprayer for small and medium scale herbicide application; with reduced drudgery and better effective herbicide application than the commonly used application machine in Nigeria, the knapsack sprayer. The knapsack sprayer was developed for spot spraying and its small coverage limits it to effectively attend to sized farms. Apart from exposing the operator to poisonous chemicals, using knapsack sprayer is very laborious as the operator is required to carry the chemical tank at the back while pumping at a steady rate and ensuring regular walking steps for efficient application. The alternative imported self-propelled herbicide boom sprayers are very costly coupled with lack of spare parts and maintenance technicians when imported. Hence the need for an appropriate boom sprayer for small and medium scale herbicide application in Nigeria. The sprayer was developed using locally available materials. A Daihatsu Hijet mini-truck, which spare parts are all locally available and maintenance technicians also readily available with fuel consumption of about 0.27 liters per hour, was deployed as the prime mover and converted to farm vehicle by the installation of 25:1 ratio gear reducer in-between its gearbox and axle to deliver operational farm spraying speeds at the wheels. Other components which include a spray pump, an herbicide tank, five impact nozzles, hoses and strainers amongst others, were also sourced locally. Laboratory and field performance evaluation of the sprayer were carried out. For the laboratory evaluation, two factors namely the height of nozzles above target and pumping pressure; which influence spray parameters were varied at three levels in a completely randomized experiment while the spray parameters of flow rate, spray volume distribution pattern, droplet size and swath were determined. The experiment were carried out at pumping pressures: (100 kPa, 200 kPa, 300 kPa) and at heights of nozzles above target: (30 cm, 45 cm, 60cm), while the spray parameters were determined. Analysis of Variance (ANOVA) with Duncan Multiple Range Test (DMRT) of the experimental results were done using Statistical Analysis Software (SAS). Linear regression model was also employed to further understand the results using MS Excel 2010. Employing impact nozzles, while spraying at 100 kPa and nozzle height above target of 45 cm setting, the machine achieved the most uniform deposition and produced the requisite droplet range of about (300 400 Âตm VMD) recommended for herbicide application. Field evaluation at nozzle height above target of 45 cm and at the three speeds indicate the maximum Application Rate, Effective Field Capacity and Field Efficiency are respectively 1,625 l/ha, 0.43 ha/h and 67%. The least Application Rate, Effective Field Capacity and Field Efficiency are respectively 1,156 l/ha, 0.3 ha/h and 47%. The cost estimate for the construction of the prototype is one million five hundred and three thousand two hundred naira (?1,503,200:00), only. The introduction of this machine into the agriculture mainstream offers our farmers an alternative herbicide applicator with less drudgery and more uniform deposition and coverage than the knapsack sprayer and at an affordable rate compared to imported large scale herbicide boom sprayers.
