Banca de DEFESA: GIOVANE LEAL DE SOUZA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : GIOVANE LEAL DE SOUZA SILVA
DATE: 23/07/2024
TIME: 13:30
LOCAL: Sala 1 PPGF
TITLE:

Effects of straw management, soil preparation and sugarcane harvesting systems on soil micronutrient content

KEY WORDS:

ssoil conservation, boron (B), copper (Cu), iron (Fe), manganese (Mn), zinc (Zn), sugarcane straw, long-term experiment

PAGES: 120
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Manejo e Tratos Culturais
SUMMARY:

Sugarcane cultivation has changed through the use of soil conservation practices, the implementation of mechanized harvesting without burning and the use of straw as a product to generate energy. Such changes bring agronomic impacts in the short, medium and long term, especially on soil fertility. There are studies in the literature regarding the impacts on pH, soil organic carbon, nitrogen, phosphorus, potassium, calcium, magnesium and sulfur content. However, regarding interference with soil micronutrients – boron, copper, iron, manganese and zinc, there are no studies. Another aspect is long-term experimentation in sugarcane, which, due to the fact that it is a semi-perennial crop, has little work evaluating the impacts of new agricultural practices beyond a crop cycle. Therefore, the objectives of this project are: To evaluate, in a long-term experiment, the influence of the sugarcane harvesting system, and the influence and interaction of the soil preparation system and the sugarcane harvesting system on incidence of diseases and the levels of micronutrients and organic carbon in the soil. Two experiments were studied, installed in the State of Espírito Santo in 1989, in an area made available by Linhares Agropecuária S. A., which was in 2021 with the cultivar RB965917 being cultivated in the sixth harvest (5th ratoon) of the fourth cycle, 32 years after installation, after 29 harvests and three renewals were carried out (1997, 2005 and 2015). The first experiment had as treatments the burning and not previously burning the sugarcane field to carry out the harvest and its alternation throughout the cycles, presented in chapter I. In chapter II the treatments were conventional soil preparation and direct planting combined with burning and not previously burning the sugarcane field for harvesting. In both experiments, the incidence of diseases, the productivity of segments of the aerial part of sugarcane, the technological parameters of the juice and stem, the levels of micronutrients boron, copper, iron, manganese and zinc, and carbon soil organic matter. Earth samples were collected at depths of 0-0.05; 0.05-0.1; 0.1-0.2; 0.2-0.3; and 0.3-0.4 m. In chapter I, the results demonstrate that the harvesting systems did not influence the health of the plots, with no symptoms of leaf and stem diseases being observed. The productivity of dry leaves, tips and stems, and the technological parameters of the juice and stem were statistically equal between the treatments. The average boron and iron levels obtained were adequate, while the other micronutrients were too low for the full development of sugarcane. Copper, iron and manganese showed significant differences between harvesting systems. The soil carbon content was obtained in the harvest without burning in all cycles in the surface layer, from 0.05 to 0.1 m and from 0.2 to 0.3 m, not different from the harvest with burned sugarcane in all cycles. . In chapter II it was observed that the health of the sugarcane field was not impacted by the proposed treatments. An interaction was observed between the soil preparation and harvesting systems for the productivity of pointers, where within raw cane, conventional tillage had greater productivity and within conventional tillage, raw cane had greater value. A simple effect was observed for the raw sugarcane harvesting system, which had higher stalk productivity than burned sugarcane, with a value of 16.64 Mg ha-1 higher. For the technological parameters of juice and stalk, higher fiber and purity values were obtained for burned cane and reducing sugars for raw cane. Only simple effects were obtained for soil preparation and harvesting system on the copper, iron, zinc and organic carbon contents of the soil. It is therefore concluded that the levels of micronutrients and organic carbon were impacted by the harvesting systems and types of soil preparation throughout the cycles, without interaction between them, mainly the levels of copper, iron and organic carbon.

COMMITTEE MEMBERS:
Externo à Instituição - CARLOS FREDERICO DE MENEZES VEIGA
Externo à Instituição - HEROLDO WEBER - UFPR
Externo ao Programa - 1282206 - JULIANO BAHIENSE STAFANATO - UFRRJExterna à Instituição - LETICIA PASTORE MENDONCA
Presidente - 1213072 - MARGARIDA GORETE FERREIRA DO CARMO