Tetflupyrolimet is a novel herbicide that inhibits dihydroorotate dehydrogenase in susceptible weeds, including those in warm-season turfgrass and rice. Given that warm-season species are managed alongside cool-season species that may be sensitive to tetflupyrolimet, research on its lateral movement within turfgrass is warranted. Field experiments were conducted in spring 2023 and 2024 at North Carolina State University to evaluate the potential downslope movement of tetflupyrolimet (400 g ai ha−1) compared with that of pronamide (1,160 g ai ha−¹), an herbicide that is known to move downslope. The studies took place on a 9.5% sloped plot of hybrid bermudagrass that had been established on Cecil sandy loam soil, under two moisture regimes at application: field capacity (≈34% volumetric water content) and saturation (≈46% volumetric water content). Before experimentation, the aboveground hybrid bermudagrass canopy was mechanically removed, and perennial ryegrass was planted as an indicator species. Herbicides were applied to treated areas (2.2 m2) upslope of data collection areas (8.6 m2), with subsequent irrigation and rainfall (2.5 cm total) 24 h after application. Downslope movement was assessed at 2, 4, 6, and 8 wk after treatment via perennial ryegrass mortality assessments made via grid (15 cm2) count. Downslope distances associated with a 50% probability of perennial ryegrass mortality (mortality50) were 1.2 to 3.6 times greater for pronamide compared to tetflupyrolimet. The maximum distance tetflupyrolimet moved was 1.1 m (regardless of soil moisture condition) each year. Comparatively, maximum downslope movement distances for pronamide were 1.5 to 1.65 m under saturated conditions and 1.5 to 1.8 m at field capacity. Overall, these findings suggest a 1.1-m buffer from sensitive species is likely sufficient to prevent undesirable injury following tetflupyrolimet applications to hybrid bermudagrass under conditions similar to this study.

Resolving the carbon (C) balance in the Amazonian forest depends on an improved quantification of production and losses of particulate C from forested landscapes via stream export. The main goal of this work was to quantify litterfall, the lateral movement of litter, and the export of coarse organic particulate matter (>2 mm) in four small watersheds (1–2 ha) under native forest in southern Amazonia near Juruena, Mato Grosso, Brazil (10°25′S, 58°46′W). Mean litterfall production was 11.8 Mg ha−1 y−1 (5.7 Mg C ha−1 y−1). Litterfall showed strong seasonality, with the highest deposition in the driest months of the year. About two times more C per month was deposited on the forest floor during the 6-mo dry season (0.65 Mg C ha−1 mo−1) compared with the rainy season (0.3 Mg C ha−1 mo−1). The measured C concentration of the litterfall samples was significantly greater in the dry season than in the rainy season (49% vs. 46%). The lateral movement of litter increased from the plateau (upper landscape position) towards the riparian zone. However, the trend in C concentration of laterally transported litter samples was the opposite, being highest on the plateau (44%) and lowest in the riparian zone (42%). Stream-water exports of particulate C were positively correlated with streamflow, increasing in the rainiest months. The export of particulate C in streamflow was found to be very small (less than 1%) in relation to the amount of litterfall produced.