Weed interference period and economic threshold level of ryegrass in wheat

Gismael Francisco Perin,Camile Thaís Castoldi,Felipe José Menin Basso,César Tiago Forte,Carlos Orestes Santin,Thalita Pedrozo Pilla,Leonardo Chechi,Milena Barretta Franceschetti,Leandro Galon,Maico André Michelon Bagnara

doi:10.1590/1678-4499.20180426

Gismael Francisco Perin, Camile Thaís Castoldi + Show 8 more

Open Access

https://doi.org/10.1590/1678-4499.20180426

Copy DOI

Abstract

ABSTRACT The study of weed interference periods and the economic threshold level (ETL) of weeds on crops allows the adoption of management methods and the rationalized use of herbicides. The objective of this study was to determine the periods of interference and to test mathematical models to determine the economic threshold level of ryegrass in the wheat crop. Two experiments were carried out in a randomized block design with four replications. The first experiment was conducted in the 2014/2015 agricultural season. The periods of interference and control of ryegrass were studied in wheat. The periods of interference and/or control were: 0, 10, 20, 30, 40, 50 and 120 days after emergence (DAE). The second experiment was conducted in the 2016/2017 agricultural season. The ETLs were studied, being the treatments composed of wheat cultivars and 12 populations of ryegrass, in competition with the respective cultivars. The results allowed concluding that the management methods of weed ryegrass must be adopted in the period between 11 and 21 days after crop emergence, which is described as a critical period of control of this weed. The wheat grain yield loss competing with ryegrass reached 59% when grown with ryegrass. For ETL, the linear regression model of the rectangular hyperbola adequately estimates grain yield losses in the presence of ryegrass. The cultivar presenting the lowest values of ETL, that is, less capacity to live with the weed, was TBIO Alvorada. The other cultivars presented similar ETL values.

Highlights

Wheat (Triticum aestivum L.) is one of the most grown cereals in the world, occupying the third place in total production
The objective of this work was to establish the periods of interference and to test mathematical models to determine the economic threshold level (ETL) of ryegrass in the wheat crop
The results showed leaf area of 42.33 and 44.70 cm2.plant–1 at 40 and 50 days after crop emergence (DAE) in the control period, in which the crop was maintained without ryegrass competition (Fig. 2)

Summary

Introduction

Wheat (Triticum aestivum L.) is one of the most grown cereals in the world, occupying the third place in total production. It is used mainly for human and animal feeding (FAO 2018). In Brazil, wheat crop is grown in the South region, being Rio Grande do Sul (RS) the second largest producer state, responsible for approximately 1.3 million tons in the 2017 agricultural season. Some factors may limit wheat yield potential, with weed plants being the main crop injury (Meulen and Chauhan 2017). It is estimated that weed plants reduce approximately 18.6% of wheat grain yield (Gharde et al 2018). It causes loses to the productivity and quality of the harvested grains, besides increasing the costs of harvesting operations, transport, and drying process of grains (Lamego et al 2013)

Objectives

Methods

Results