Banca de DEFESA: LARISSA BRASIL DE SOUZA CAVALHEIRO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : LARISSA BRASIL DE SOUZA CAVALHEIRO
DATA : 25/11/2019
HORA: 08:00
LOCAL: Sala 01 - PPGF
TÍTULO:

IMAZAPYR LEACHING IN SOIL FROM THE AREA UNDER RAIL INFLUENCE

PALAVRAS-CHAVES:

imazapyr, leaching, bioassay

PÁGINAS: 79
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Matologia
RESUMO:

Weed control is a challenge for rail maintenance. The main control method adopted by companies is the chemical one. One of the herbicides registered for use in railways is imazapyr. In this sense, the objective was to evaluate the control efficiency and imazapyr dynamics in soil under influence of railroad inserted in the Atlantic Forest biome. The first trial was carried out in the field with treatments T1 (control without herbicide), T2 (875 g ha-1 ea), T3 (1312.5 g ha-1 ea), T4 (1750 g ha-1 ea). , T5 (3500 g ha -1 area) in the randomized block design with four replications. Percentage of control (%) evaluations were performed at 20, 40, and 60 DAA (days after application) with 0% for absence and 100% for total control. After 60 DAA reinfestation was evaluated. The second evaluated the mobility of imazapyr in soils coming from the railroad-pierced APP area as a function of herbicide doses, soil layer depth, precipitation depth in relation to time after herbicide application (1, 7 and 14 DAA). ). The treatments were arranged in a factorial scheme (3 x 4 x 3), in a randomized block design with four replications. Factor A constituted by the control and two doses of the herbicide (1250 g ha-1 ea and 2500 g ha ha 1 ea), factor B constituted by the depths in the column and factor C by three precipitation blades: 0, 20 and 50 mm. The assay was mounted on 10 cm diameter 40 cm high PVC columns. The herbicide was applied with a pressurized costal sprayer to CO². To open the columns, the soil was removed at depths of 0-10, 10-20, 20-30 and 30-40, and transferred to 250 mL pots. To detect the presence of the herbicide was used the bioindicator species (Citrullus lanatus) for visual evaluation, giving grades of 0% to 100% for absence or death of the plant. On these same dates, chlorophyll a fluorescence was also evaluated in the bioindicator plants at 20, 30 and 35 DAS. At 35 days after sowing were evaluated the parameters of plant growth: shoot dry mass (MSPA), root dry mass (MRS), root length (CR), shoot length (CPA). The data were subjected to analysis of variance by the F test (p <0.05) and when significant interactions were performed the offsets and means compared by the Tukey test (p <0.05). In experiment I, an increase in weed control was verified at all times of evaluations due to the increase of imazapyr dose. The maximum control observed was 30% in an evaluation performed at 20 DAA. In experiment II the data showed significant interaction (p ≤ 0.05) between imazapyr herbicide doses, precipitation volume and depth for all evaluated times (1, 7 and 14 DAA) in all analyzed variables. However, regardless of the evaluated time, rainfall and precipitation time after application, imazapyr promoted compromise in the photosynthetic apparatus of the bioindicator, which showed phytotoxicity and reduced root and shoot dry mass at different soil depths. . It was concluded that imazapyr provided insufficient weed control along the railway in the study section and presented soil mobility under the evaluated conditions.

MEMBROS DA BANCA:
Presidente - 1905333 - AROLDO FERREIRA LOPES MACHADO
Externo ao Programa - 2466219 - CAMILA FERREIRA DE PINHO
Externo à Instituição - FRANCISCO CLAUDIO LOPES DE FREITAS - UFV