Field dissipation ofS-metolachlor in organic and mineral soils used for sugarcane production in Florida

摘要

Dissipation ofS-metolachlor, a soil-applied herbicide, on organic and mineral soils used for sugarcane production in Florida was evaluated using field studies in 2013 to 2016.S-metolachlor was applied PRE at 2,270 g ha(-1)on organic and mineral soils with 75% and 1.6% organic matter, respectively. The rate of dissipation ofS-metolachlor was rapid on mineral soils compared with organic soils. Dissipation ofS-metolachlor on organic soils followed a negative linear trend resulting in half-lives (DT50) ranging from 50 to 126 d.S-metolachlor loss on organic soils was more rapid under high soil-moisture conditions than in corresponding low soil-moisture conditions. On mineral soils, dissipation ofS-metolachlor followed an exponential decline. The DT(50)ofS-metolachlor on mineral soils ranged from 12 to 24 d. The short persistence ofS-metolachlor on mineral soils was likely attributed to low organic matter content with limited adsorptive capability. The results indicate that organic matter content and soil moisture are important for persistence ofS-metolachlor on organic and mineral soils used for sugarcane production in Florida.