Interval between the application of metsulfuron-methyl and sowing soybean in different production environments

Naiara Guerra,Wilian Jochem,Lucas Barco Kopko,Adriano Lopes Carneiro,Jaqueline Schmitt,Antonio Mendes De Oliveira Neto

doi:10.5935/1806-6690.20200032

Abstract

The persistence of herbicides in the soil is extremely important for controlling weeds during the critical period of weed interference, and for determining which substitute crops might be sown. The aim of this study was to evaluate the effect of metsulfuron-methyl when applied at different times in relation to sowing soybean, seeking to determine a safe interval between its application and sowing the legume under different conditions of soil and climate. Two experiments were conducted, one in the district of Campo Mourao in the state of Parana (PR) (2014/15 crop) and the other in Curitibanos in the state of Santa Catarina (SC) (2015/16 crop). Both experiments were carried out in a randomised block design with four replications. The treatments were arranged in a 2 x 6 + 1 factorial scheme, where factor A represented two doses of metsulfuron-methyl (1.98 and 3.96 g ha-1), and factor B six different intervals between applying the metsulfuron-methyl and sowing the soybean (0, 15, 30, 45, 60 and 75 days after application - DAA), in addition to a control without the application of herbicide, to serve as a standard for comparison. The following were evaluated: percentage phytotoxicity, plant height, stand, number of pods per plant, 100-grain weight and productivity. A difference was seen in the persistence of metsulfuron-methyl for the experiments in Campo Mourao PR, and Curitibanos SC, and was greater for Campo Mourao. The safe interval between applying the metsulfuron-methyl and sowing the soybean was 17 days for the experiment in Curitibanos and 40 days for Campo Mourao. Precipitation volume, pH and organic matter are the main factors to possibly have influenced this interval.

Highlights

The persistence of herbicides is extremely important for controlling weeds during the critical period of weed interference, and for determining which substitute crops might be sown
The symptoms of phytotoxicity seen in the soybean plants were characterised by growth inhibition and intense chlorosis, similar to the symptoms seen by Alonso, Oliveira Junior and Constantin (2013) after sowing soybean in soil treated with metsulfuronmethyl
A difference was seen in the persistence of metsulfuron-methyl between the experiments in Campo Mourão and Curitibanos

Summary

Introduction

The persistence of herbicides is extremely important for controlling weeds during the critical period of weed interference, and for determining which substitute crops might be sown. Metsulfuron-methyl is an herbicide of variable persistence in the soil It acts in inhibiting the enzyme acetolactate synthase (ALS), and belongs to the group of sulfonylureas. It is recommended in winter cereals, rice, pasture, coffee and sugar cane (RODRIGUES; ALMEIDA, 2011), its use has been widened to include autumn weed management, such as Conyza spp (MOREIRA et al, 2010; PAULA et al, 2011), especially in southern Brazil. It is characterised by high biological activity, being effective at very low doses, and by its broad spectrum of action (VARGAS; ROMAN, 2005)

Objectives

Methods

Results