Plantabilidade de soja em lavouras comerciais no município de Pato Branco - PR

Abstract

This study evaluated plantability parameters in commercial soybean (Glycine max (L.) Merr.) fields in Pato Branco, Paraná, Brazil. We analyzed seeders, operators, and operational variables with emphasis on seed placement depth, longitudinal distribution uniformity, plant stand, and fertilizer calibration. The objectives were to identify the depth ranges used by farmers and infer an optimal working range; quantify the target versus achieved plant stand and locate sources of stand errors; quantify target versus delivered fertilizer rates and potential causes of deviation; and determine the percentages of normal plants, doubles, misses, and the coefficient of variation (CV). Data collection combined field measurements (seed depth, plant stand, fertilizer distribution) and operator/operation information. Twenty-seven seeders of different brands, models, metering systems, and years of manufacture were assessed. Descriptive statistics supported exploratory analysis, and results are presented as graphs. Seeding depth ranged from 2.0 to 6.2 cm, with settings predominantly between 2.0 and 4.0 cm; higher soil moisture favored seed “enveloping” and greater heterogeneity of effective depth. Stand discrepancies between targets and outcomes were frequent across farms, linked to operational factors and the use of saved seed, which impaired germination, vigor, and spatial uniformity. Fertilizer delivery was generally well calibrated, with only punctual deviations. In longitudinal distribution, no seeder exceeded 64% acceptable spacings; mean values were low and CVs were high (60% to >100%), classifying performance from regular to unsatisfactory. Uniformity reductions >50% were associated with yield penalties. We conclude that better machine adjustment, operator training, and high-quality seed are critical to improving stand uniformity and yield potential in the region.