Banca de DEFESA: JULIA RODRIGUES NOVAIS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : JULIA RODRIGUES NOVAIS
DATA : 27/02/2023
HORA: 08:00
LOCAL: Google Meet
TÍTULO:

DYNAMICS OF PYROXASULFONE IN SOILS WITH CONTRASTING TEXTURES

PALAVRAS-CHAVES:

herbicide, bioindicators, leaching, residual

PÁGINAS: 61
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitossanidade
ESPECIALIDADE: Defesa Fitossanitária
RESUMO:

The use of herbicides contributed to the expansion of agriculture, which are diverse for weed control and their behavior in the environment is influenced by factors. Prolonged stay can cause environmental maintenance and excessive leaching of herbicides. The pyroxasulfone environment recently and the pyroxasulfone environment are information pyramids in Brazil and are not part of their behavior. In this sense, the use of bioindicator plants an affordable and effective alternative in the determination is herbicides in the soil. The objective of this work was to evaluate the sensitivity of lettuce, cucumber and whey to the herbicides pyroxasulfone and flumioxazin in order to determine a species with bioindicator potential in soils with different textures. Subsequently, when determining a bioindicator species, a study was carried out on the behavior of pyroxasulfone and pyroxasulfone + flumioxazin in the environment, through the analysis of the leaching potential, carried out in sandy loam soil and residual effect, in soils with contrasting textures. For the selection of bioindicators, four experiments were carried out with two types of soils (Red Latosol and Quartzarenic Neosol). The treatments consisted of doses of pyroxasulfone (3.1; 6.2; 12.5; 25; 50 and 100 g a.i. ha^-1) and pyroxasulfone + flumioxazine (3.1 + 2.07; 6.2 + 4 .13; 12.5 + 8.33; 25 + 16.67; 50 + 33.33; 100 + 66.67 g a.i. ha^-1) applied pre-emergence and a control without application. The analysis of the leaching potential was performed using a soil column bioassay (Neossolo Quartzar) using cucumber as a bioindicator. Irrigations of 0, 30, 60 and 90 mm were simulated after an application of pyroxasulfone (100 g a.i. ha^-1) and pyroxasulfone + flumioxazin (100 + 66.67 g a.i. ha^-1). The study on the residual effect will be carried out in two types of soils (Red Latosol and Quartzarenic Neosol). Two doses of pyroxasulfone (100 and 200 g a.i. ha^-1) and pyroxasulfone + flumioxazin (100 + 66.67 and 200 + 133.33 g a.i. ha^-1) will be used, seven times of application (0, 15, 30, 45, 60, 75 and 90 days between herbicide application (DAA) and bioindicator sowing), one control without application and four replications. The sowing of the cucumber bioindicator will be carried out at 0 DAA. For both experiments, phytotoxicity assessments were performed at 7 and 14 DAA, while plant height, root length, green biomass and dry biomass of both bioindicators were evaluated at 21 DAA. It was found that lettuce was the most sensitive species selected for both herbicides, however, its high sensitivity to adverse weather conditions may make its use in practical tests difficult. However, cucumber and sorghum also proved to be potential candidates as bioindicators and could be used in bioassays for these herbicides. For the leaching experiment, it was found that increasing irrigation depths provided displacement of herbicide molecules to a depth of 20-25 cm for pyroxasulfone alone and in association with flumioxazin. When water depths of 90 mm were applied, greater interference was observed in the development of cucumbers in the deeper layers, evidencing the greater leaching of herbicides when subjected to intense rainfall. Regarding the residual effect, it is expected that pyroxasulfone and pyroxasulfone + flumioxazin have a superior residual effect in clayey soil, compared to sandy loam texture, and that they cause phytotoxicity in bioindicator plants, making it possible to determine the period that the herbicides remain assets in the environment.

MEMBROS DA BANCA:
Presidente - 221918004 - MIRIAM HIROKO INOUE
Interno - 138379001 - DEJANIA VIEIRA DE ARAUJO
Externo à Instituição - KASSIO FERREIRA MENDES - UFV