Design, Construction and Evaluation of a Semi-Automatic Seeder for Seedling Tray

Transplantation is one of the most effective ways to increase economic efficiency of some agricultural products like rice and vegetables. The aim of this study was to design, construct and evaluate a simple and inexpensive seeder for fast and accurate seeding in transplant trays. Modeling was performed using CATIA software. The prototype consists of a cylindrical vacuum distributor with holes of 1 and 2 mm diameters, pressure brake mechanism, the cam & forwarding mechanism for pushing tray step by step, and a power transmission mechanism (consisting of the sprocket and belt). To evaluate the machine and determine the optimum conditions, average operating errors including none-planting and multiple-planting errors were obtained for two kinds of seeds (cucumber and lentil). A factorial experiment based on a completely randomized design was applied. Independent variables were the diameter of holes (1 and 2 mm) and pressure (-8 and -15 kpa for cucumber and -7 and -13 KPa for lentils). The results showed that the better performance was achieved under higher vacuum condition and smaller diameter. The optimum condition was obtained at diameter of 1 mm and pressure of -15 and -13 KPa for the seeds of cucumber and lentil, respectively. The optimal capacity was 240 trays (25200 seed) per hour and an average of none-planting and multiple-planting errors were 19.1% and 8.9%, 16.13% and 7.81% for the seeds of cucumber and lentil, respectively.