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

Abstract

Dissipation of S-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 of S-metolachlor was rapid on mineral soils compared with organic soils. Dissipation of S-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 of S-metolachlor followed an exponential decline. The DT50 of S-metolachlor on mineral soils ranged from 12 to 24 d. The short persistence of S-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 of S-metolachlor on organic and mineral soils used for sugarcane production in Florida.

Modeling volatilization emissions of soil-applied pesticides under agricultural field conditions

“…Metolachlor is semi-volatile and slightly immobile in soil. High fluxes of metolachlor could occur when wet soil condition increases the soluble concentrations and drives the flux across the boundary layer ( Gish et al, 2009 ; Fernandez et al, 2020 ). Dry soil conditions allow the metolachlor concentrations to accumulate in the soil that cannot overcome the boundary layer resistance in absence of a significant upward evaporation rate.…”

Effect of depth of flooding on growth and fecundity of fall panicum (Panicum dichotomiflorum)

“…The trays were kept in a greenhouse maintained at a maximum of 30 C under natural light before being transplanted into round 2.36-L (17 cm top diameter and 16 cm height) pots filled with Dania muck (Euic, hyperthermic, shallow Lithic Haplosaprists) soil, pH 7.3, with 74% organic matter from fields used for rice production at the EREC. Soil pH and organic matter content were determined using the method described by Fernandez et al (2019).…”

Influence of soil water content on growth and panicle production of fall panicum (Panicum dichotomiflorum)

“…The soil was Dania muck (Euic, hyperthermic, shallow Lithic Haplosaprists) with 7.3 pH and 74% organic matter. Soil pH and organic matter content were determined using the method described by Fernandez et al (2019). The soil was air-dried and passed through a 13-mm sieve to remove debris prior to use.…”