Differential tolerance of eucalyptus clones to sulfentrazone applied in different soil textures

This study aimed to evaluate the visual injury and concentrations of chlorophyll in two eucalyptus clones submitted to sulfentrazone application, at different doses and in soils with different textures. Experiments were performed utilizing two soil textures (sandy and clayey). The treatments were arranged in a factorial scheme of two (clones) x four (sulfentrazone doses), in a completely randomized experimental design with four replications. Two eucalyptus clones were utilized: Eucalyptus urophylla (472) and Eucalyptus urograndis (132), and were tested at doses of 200, 400 and 600 g of sulfentrazone ha-1 and one control without herbicide application. The different herbicide doses were applied onto the soil, and then the plants were transplanted to pots. Visual injury evaluations occurred at 15, 35, 62 and 90 days after application of the different sulfentrazone doses whereas leaves and soil were collected on days 15, 45 and 90 after herbicide application to determine the chlorophyll levels. At 90 days after application, the plants were harvested and their respective dry masses determined. Both eucalyptus clones presented higher intoxication levels in sandy soil while the E. urophylla clone proved more sensitive in relation to sulfentrazone application. The visual injury levels observed in the two clones was proportional to the sulfentrazone dose in both soils, while sulfentrazone availability was much greater in sandy than clayey soil. The highest sulfentrazone doses in both soils promoted diminished levels of chlorophyll.