Weed Control J 2021; 20: e202100729

Research Article

Sourgrass control after preemergence herbicide application in soil with increasing levels of soybean and corn straw

DOI: 10.7824/wcj.2021;20:00729

Abstract

Background

Straw, common in areas where no-till was adopted, can become a barrier for the applied herbicides to reach their destination, the soil. There is no information on the ability of the new herbicide pyroxasulfone to overcome this barrier and promote effective preemergence weed control.

Objective

To evaluate the effectiveness of pyroxasulfone in weed control when applied in different levels of straw, comparing it with herbicides available in the Brazilian market.

Methods

Two different experiments were carried out in a greenhouse. The experimental design used was completely randomized in a 4 x 4 factorial scheme, with six replications. The treatments consisted of the application of pyroxasulfone (100 g ha-1), S-metolachlor (1960 g ha-1) and trifluralin (1125 g ha-1) on different levels of soybean and corn straw (0, 1, 3 and 5 t ha-1). The weed used was sourgrass (Digitaria insularis). The pots received a 30 mm slide of water. The control effectiveness of treatments was verified at 7, 14, and 28 days after application.

Results

The herbicide pyroxasulfone was able to transpose up to 5 t ha-1 of soybean and corn straw after precipitation of 30 mm. S-metolachlor and trifluralin showed a reduction in the control efficacy when applied to soils with higher amounts of straw.

Conclusions

The ability of the herbicide pyroxasulfone to transpose soybean or corn straw after a 30 mm precipitation and promote the control of sourgrass was ≥ S-metolachlor and > trifluralin.