EVALUATION OF THE EFFICACY OF PRE-EMERGENCE HERBICIDES FOR THE CONTROL OF COLONY GRASS IN DIFFERENT SOWING FLOWS WITH DIFFERENT RESIDUES FROM THE SUGARCANE INDUSTRY

• Grant number: 24/11050-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2024
• End date: September 30, 2025
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Patrícia Andrea Monquero
• Grantee: Arthur José Brumatti
• Host Institution: Centro de Ciências Agrárias (CCA). Universidade Federal de São Carlos (UFSCAR). Araras , SP, Brazil

Abstract

The presence of weeds that are difficult to control in a crop has direct negative effects on its growth and development, competing for water, light and nutrients, as well as making harvesting difficult. Normally, in sugarcane cultivation, herbicides are used in pre-emergence conditions, in order to achieve a greater spectrum of action, a long residual effect and a reduction in costs. It is therefore interesting to know how long these herbicides are effective in controlling weeds and how different residues such as vinasse, straw and filter cake can affect the effectiveness of herbicides. The aim of this study is to evaluate the efficacy of the herbicides pyroxasulfone + flumioxazin, sulfentrazone, s-metolachlor and pendimethalin (registered for sugarcane) at different germination rates, when applied pre-emergently to Panicum maximum in different situations: bare soil, with sugarcane straw, with vinasse and with filter cake. The experiments will be carried out in a greenhouse following a completely randomized experimental design for each herbicide applied at a commercial dose (pyroxasulfone + flumioxazin, sulfentrazone, s-metolachlor and pendimethalin) in a 4 x 6 factorial scheme, with four replications. The first factor will be made up of 4 application situations: applied directly to the soil; applied to 10 t ha-1 of straw on the soil; soil with the presence of vinasse; soil with the presence of filter cake, and the second factor will be made up of 6 sowing periods for Panicum maximum (colonião grass) - 0, 7, 15, 30, 45 and 60 days after application, and a control without the use of chemical control in each period. The plants will be assessed for phytotoxicity at 7, 14, 21 and 28 days after sowing (DAS). At 30 DAS, the plants will be cut off close to the ground and dried in a forced-air oven at 65°C for 48 hours in order to obtain the dry mass of the aerial part.