Development of a low-cost multi-hybrid variable rate system for horizon- tal disk planter
Authors:   , Dambroz Giovani Prates Bisso 
Published: October 2023

Food security and the environmental issues are two main challenges of modern times. Due to the economic growth of societies, there is an increase of meat consumption. As a result, demand of feed for livestock is drastically increasing. Plant breeding, fertilizer technology, soil biology, and precision agriculture are some of the areas that could contribute to the improvement of agricultural output efficiency, which is imper- ative. Seeding operations can become more efficient by using precision agriculture technologies such as variable rate seeding and multi-hybrid seeding. However, there are currently no technologies for multi-hybrid seeding compatible with horizontal disk seed meters, which are vastly used in emerging countries. This study aims to develop a low-cost, electric-driven multi-hybrid variable rate system for row crop planters equipped with horizontal disk seed meters, and to compare the developed system’s planting performance with that of a ground-wheel-driven seed meter. The multi-hybrid system was developed based on a product design methodology. A pro- totype of the system was manufactured in PETG using a desktop 3D printer. The multi-hybrid system has three working positions - open for seed type A, open for seed type B, and closed - operated by a servomotor. The controller is composed of a single-board computer and other electronic components, and operates the multi- hybrid system and an electric-driven horizontal disk seed meter in fixed or prescrip- tion map-based variable rate. Total cost of the electric-driven multi-hybrid variable rate seed meter (MVSM) was under USD400. Four experiments were conducted to evaluate the MVSM. The first compared the MVSM with a factory-built, ground- wheel driven seed meter (GWSM) at three seeding rates (3, 3.5, and 4.1 seeds per meter) in terms of planting performance. The second compared the planting perfor- mance of four positions of the MVSM - open A, B, and closed A, B - at three seeding rates. The third evaluated the transition distance from one seed type to the other at three seeding rates. The fourth evaluated the planting performance of the devel- oped electric-driven variable rate seed meter without the multi-hybrid system (VSM) at three seeding rates. All experiments were conducted at 4 km · h − 1 with corn seed. Data from the first and fourth experiments show a tendency of decrease in planting performance as seeding rate increased across all systems tested and a higher dispersion of seed spacing distribution produced by the MVSM. The GWSM outperforms the MVSM in terms of planting performance. An increase in seeding rate negatively affects planting performance regardless of the system. The open B and closed B po- sitions of the MVSM have the lowest planting performance. An increase in seeding rate negatively affects planting performance regardless of the position. The switch be- tween seed types B to A produces mean transition distances under seven meters. Seed type switching from A to B is unsatisfactory. The multi-hybrid system negatively af- fects the electric-driven seed meter’s performance at all seeding rates. Although seed type switching needs improvement, the MVSM could potentially replace the GWSM with the advantage of on-the-go seeding rate adjustment. Keywords: Multi-hybrid. Variable rate seeding. Seed spacing.