Influence of soil class, straw and rainfall choice on pyroxasulfone leachate

• Grant number: 22/00949-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2022
• End date: April 30, 2023
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Pedro Luis da Costa Aguiar Alves
• Grantee: Vitor Adriano Benedito
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

It is of great importance to understand the behavior of herbicides in different soils, relating it to the characteristics of these soils, the presence of straw in cover, and rainfall to achieve an efficient positioning in the management of weeds. In view of this, the objective was to verify if pyroxasulfone, a herbicide recently registered in Brazil, will present different percolation depending on the type of soil, straw, and rainfall. For that, four experiments will be developed, each one corresponding to a type of soil, which will be used to fill the PVC pipes. Once the filling is completed, they will be moistened to 65% of their saturation capacity and the sugarcane straw will be deposited on the exposed surface of the tubes in amounts equivalent to 0, 5, and 10 t/ha, when it will be done the application of pyroxasulfone at a dose of 200 mL pc/ha. After 24 hours after application, rainfall simulations will be carried out in amounts equivalent to 10, 20, and 40 mm. After 72 hours of the last rainfall simulation, the straws will be removed from the surface of the columns and the tubes will be placed in a horizontal position and opened longitudinally and the sowing of Cucumis sativus will be carried out at 1 cm intervals. For each experiment, the experimental design will be completely randomized, with the treatments arranged in a 4x3+T factorial scheme, in 4 replications, in which the four amounts of sugarcane straw are submitted to three rainfall simulations with absolute control, totaling 52 experimental plots (PVC tubes), which after opening will result in 8 replications per treatment. Daily after application, until the emergence of the indicator plant is stabilized, the number of emerged seedlings will be counted. During this period, visual phytotoxicity scores will be assigned according to the EWRC (1964) rating scale. At the end of the experimental period, the remaining aerial parts will be cut close to the soil surface, bagged, identified, and placed to dry in an oven at 60ºC for 96 hours, to determine the dry mass. The results obtained will be submitted for analysis of variance by the F test. When significant, the means will be submitted to regression analysis as a function of the amounts of straw and/or precipitation versus the sowing distance. (AU)