Phytosanitary treatment of soybean seeds associated with polymers: physiological quality, retention and absorption of active ingredients

Phytosanitary seed treatment is widely used to protect soybean seeds and seedlings during critical establishment phase. This study evaluated the physiological quality of seeds, as well as retention and absorption of active ingredients when treatments were applied alone or combined with polymers. Experiments were conducted in a completely randomized design under laboratory, seedbed, and field conditions at the Federal University of Santa Maria, Brazil, using the cultivar NEO 590 I2X. Seeds were treated with a commercial product (Standak® Top UBS: fipronil, thiophanate-methyl, and pyraclostrobin), along with four commercial polymers. Analyses included germination, seedling growth, biomass accumulation, and active ingredient leaching and absorption at the VC stage using UHPLC-MS/MS. Results showed that the effects of seed treatments on physiological quality varied depending on the treatment and evaluated variables. Polymer effects on active ingredient retention and leaching depended on treatment combinations. Leaching of active ingredients was minimal, and seedling absorption did not exceed 3.78% of the applied dose per seed, indicating limited uptake under the evaluated conditions. Overall, active ingredient behavior varied according to compound characteristics and environmental conditions, with limited uptake and mobility in the soil–plant system under evaluation. These results should be interpreted considering the cultivar and experimental conditions.