Development of a Mechanically Assisted Pneumatic Metering Mechanism for High-Speed Planting of Soybean

A planter for planting soybean seeds up to 1.94 m∙s−1 (7 km∙h−1) was designed. In this machine, a hybrid metering mechanism was developed in which singulation was done with the help of vacuum pressure and conveying of seeds was done by cellular ring. The metering mechanism was evaluated for seed plates with three different numbers of holes (64, 74 and 84); three vacuum pressures (2, 3 and 4 kPa) and at three forward speeds (0.83, 1.39 and 1.94 m∙s−1). The effects of forward speeds on different indices were found insignificant at 5% confidence level. The optimum value of different indices i.e., miss index, multiple index, quality of feed index and precision index were observed for 84 number of seed holes at 3kPa vacuum pressure for 0.83, 1.39 and 1.94 m∙s−1. In field evaluation of the machine, the average width of operation, plantto plant spacing, depth of operation, field capacity, and field efficiency were 2.1 m, 9.7 × 10−2 m, 5.2 × 10−2 m and 0.9ha∙h−1, 72% at 1.94 m∙s−1 speed of operation and 0.1 m plant to plant spacing setting. The metering mechanism was foundsuitable for planting soybean up to 1.94 m∙s−1 (7 km∙h−1).