Development of a Metering Device for a Garlic Planter

Planting has the highest input cost in garlic production and is done manually. A metering device was designed and built for a two-wheel, push-type garlic planter. The metering mechanism consists of gathering cups attached to a moving chain, which is driven by a pair of 16-tooth sprockets. These sprockets are in turn driven by a spiked rear wheel. The average planting distance was 21.25 cm. An optimal picker speed was found to be 0.037 m/s. Tests revealed that the singulation efficiency achieved was 69.65%, close to the predicted value of 71.27%. However, there was a relatively high missed hill percentage of 19.9%, in contrast to the predicted value of 5.88%. This was attributed to garlic cloves bouncing out of the gathering cup due to vibration, leading to a significant difference in missed hill percentages between the actual and predicted values. It is recommended to improve the design of the gathering cup in releasing the cloves to address this issue.