Impact of on-farm and industrial treatments on seed longitudinal distribution for soybeans

ABSTRACT Adequate seed placement is essential for consistent crop emergence and initial growth. Pneumatic seed metering systems offer superior longitudinal seed distribution accuracy compared to traditional methods, yet certain factors can influence this precision. For instance, seed physical properties may be altered by phytosanitary treatments applied either on-farm or industrially. This study examined the effects of phytosanitary treatment type and graphite addition on soybean seed deposition using an electric-driven pneumatic feeder under simulated sowing conditions. Seed distribution was monitored with an optical sensor. Four treatment groups were established: untreated without graphite, untreated with graphite added, on-farm treated with graphite, and industrially treated with graphite. Parameters assessed included average spacing between seeds, coefficient of variation, precision index, multiple and failed spacings, and percentage of acceptable spacing. Results indicate that prior seed treatment does not significantly affect overall planting accuracy. However, seed spacing varied between the untreated and on-farm treated groups, with the latter demonstrating closer proximity to optimal values. Both on-farm and industrial treatments yielded more uniform seed deposition, as indicated by a lower coefficient of variation. Regardless of seed treatment, the pneumatic feeder consistently performed effectively.