Pennisetum glaucum in reducing ecotoxicity in soil with tebuthiuron, thiamethoxam and vinasse

Abstract

The purpose of this study was to evaluate the ecotoxicological effects on soils containing associations of the herbicide tebuthiuron (TBT), the insecticide thiamethoxam (TMX), vinasse (VIN), and millet (Pennisetum glaucum) cultivation. We conducted the experiment under greenhouse conditions using a completely randomized design with five replications. Treatments consisted in soil application of tebuthiuron (1000 g ha-1 a. i), thiamethoxam (330 g ha-1 a. i), vinasse (113 m3 ha-1) with or without P. glaucum cultivation. The monitoring extended to 50 days after sowing (DAS) and evaluated the ecotoxicological potential from Lactuca sativa seeds as test-organism. Seed germination and root development determined the germination index (GI) concerning the negative control, which was prepared with water. Thus, P. glaucum highlighted a beneficial influence on soil health, thereby mitigating the ecotoxicological effects of TBT and TMX. Results emphasized the importance of the timing in soil sample collection, where early collections after plant seeding result in higher germination rates and rapid soil health improvements. Furthermore, vinasse reduced the ecotoxicological impact of pesticides and TBT presence presented harmful effects to test-organism. The interaction between P. glaucum growth period and soil sampling had a profound impact on ecotoxicity bioassays, which highlighted the importance of early intervention. Therefore, P. glaucum and vinasse can be valuable components in effective phytoremediation strategies, pointing towards future research and enhancement of approaches for sustainable treatment strategies of agricultural soils with pesticides.