Banca de DEFESA: RITA DE CÁSSIA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RITA DE CÁSSIA SILVA
DATE: 10/03/2022
TIME: 08:30
LOCAL: Online
TITLE:

Straw x precipitation relation on the mobility of pre-emergent herbicides

KEY WORDS:

soybean; rainfall, residual; interceptation

PAGES: 62
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Manejo e Tratos Culturais
SUMMARY:

Understanding the different ways in which herbicide molecules interact with the characteristics of the environment is essential to predict the dynamics of these molecules in the soil in different production systems. Therefore, the objective of this research was to analyze the interference of corn straw and precipitation on the mobility and residual effect of pre-emergent herbicides diclosulam, trifluralin, flumioxazin, s-metolachlor and sulfentrazone. The experiments were conducted one for each herbicide, as follows: diclosulam (35 g ai ha-1), flumioxazin (60 g ai ha-1), s-metolachlor (1800 g ai ha-1), sulfentrazone (600 g ai ha-1), ha-1) and trifluralin (1800 g ai ha-1) with experimental design used in randomized blocks with four replications. The treatments were constituted in a 3 x 3 factorial scheme, being the levels of corn straw (0, 50 and 100% - corresponding to 3 t ha-1) and the periods of precipitation after herbicide application (1, 10 and 20 days) in addition to controls without application of herbicides, in the presence and absence of straw. Herbicide application was carried out with the aid of a backpack sprayer, equipped with CO2, coupled to a bar with two TT110.02 tips, spaced at 50 cm, working at a pressure of 2.8 bar and calibrated to apply 150 L ha-1 of syrup. After the application of herbicides, a simulation of 20 mm of precipitation was performed through a system installed in the greenhouse, according to the precipitation periods defined above. The experimental unit consisted of pots with a capacity of 5L of soil, where weeds were sown as indicators of the herbicides used, being the ragweed (Commelina benghalensis L.), for the herbicides flumioxazin, sulfentrazone, diclosulam and s-metolachlor and the crow's foot (Eleusine indica), for the herbicide trifluralin. Control evaluations were performed at 14 and 21 DAA and at 42 DAA the shoot dry mass was evaluated. Soil and straw samples were collected for ultra performance liquid chromatography (UHPLC) analysis at 42 DAA. And a new seeding was performed at 42DAA to evaluate the residual effect with control evaluations at 21 and 35 DASR. The data generated in the experiment were submitted to analysis of variance - ANOVA (p≤0.05) by the R Studio program and the graphs made by the SigmaPlot program. In the application directly to the soil and on the straw, diclosulam, sulfentrazone and trifluralin presented higher percentages of control in all periods of precipitation. On the other hand, flumioxazin and s-metolachlor showed lower percentages of control in the presence of straw, regardless of rainfall periods. The residual effect of diclosulam and sulfentrazone was lower when it received rain after 1 day of application than in longer periods of drought. The presence of straw did not promote a prolonged residual effect for flumioxazin, s-metolachlor and trifluralin, regardless of the different rainfall conditions.

BANKING MEMBERS:
Externo à Instituição - RUBEM SILVÉRIO DE OLIVEIRA JUNIOR
Interno - 1905333 - AROLDO FERREIRA LOPES MACHADO
Presidente - 2466219 - CAMILA FERREIRA DE PINHO