Banca de DEFESA: JACIARA DIAVÃO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JACIARA DIAVÃO
DATE: 08/04/2022
TIME: 08:00
LOCAL: INSTITUTO DE ZOOTECNIA
TITLE:

Strategies for recovery and reform of degraded Urochloa decumbens pasture in Zona da Mata of Minas Gerais

KEY WORDS:

Liming and pasture fertilization. Morphological composition. Soil density. Forage mass and accumulation. Leaf ratio: culm. Soil resistance to penetration. Nutritional value of forage. Soil chemical variables.

PAGES: 110
BIG AREA: Ciências Agrárias
AREA: Zootecnia
SUBÁREA: Pastagem e Forragicultura
SUMMARY:

DIAVÃO, Jaciara. Strategies for recovery and reform of degraded Urochloa decumbens pasture in Zona da Mata of Minas Gerais. 2022. 102p. Thesis (Doctorate in Animal Science). Institute of Animal Science, Department of Animal Nutrition and Pastures, Federal Rural University of Rio de Janeiro, Seropédica, RJ, 2022. The aim of the present study was to evaluate different fertilization strategies for the recovery and reform of degraded pasture in the chemical and physical properties of the soil, mass, accumulation and nutritional value of forage and canopy structure. Five treatments with four replications (blocks) each were used. The treatments were: control (T1) – degraded Urochloa decumbens pasture without fertilization; T2 – surface application of limestone; T3 – superficial application of limestone and phosphate fertilization; T4 – actions applied to T3 added to fertilization with nitrogen and potassium; T5 – the actions applied to T4 associated with the reform with implantation of Megathyrsus maximus cv. BRS Quênia. For soil chemical and physical variables, the effects of soil depths (0 to 5, 5 to 10, 10 to 20 and 20 to 40 cm) were also tested. All variables were analyzed in a randomized complete block design, being those chemical and physical soils in a split-plot arrangement with treatments in the plot and soil depths in the subplot, and the other variables of canopy and forage under repeated measures in time. in five seasons (summer 1, autumn 1, spring 1, summer 2 and autumn 2). Data were analyzed by SAS® under specific procedures for the variables studied. Higher levels of Ca, Mg, K S, V and organic carbon were obtained at the lowest depth (0 to 5 cm). Lower soil density, weighted mean diameter and geometric mean diameter were obtained at the greatest depth. Greater resistance of the soil to penetration was obtained in the depth of 15 to 20 cm. Higher volumetric soil water content was obtained in the summer. There was an interaction effect between treatment and season of the year for the variables of canopy structure, mass, accumulation and nutritional value of the forage. Higher height, shorter interval between cuts, better leaf:stem ratio, higher NDF, CP and IVDMD and lower SPAD chlorophyll index were obtained for the treatment with the BRS Quênia (T5) cultivar. Higher total accumulated forage mass was observed for T5 and T4 in the seasons autumn 1 (+ 1376 kg ha-1), summer 2 (+ 1352 kg ha-1) and autumn 2 (+ 913 kg ha-1), in addition to superiority of 2368 kg ha-1 and 3984 kg ha-1 for T5, in relation to the other treatments, in the seasons summer 1 and spring 1, respectively. The use of limestone, associated with phosphate, nitrogen and potassium fertilization does not promote changes in the physical variables of the soil. However, these associations improved all chemical properties, especially in the lowest soil depth (0 to 5 cm). The association between lime application and maintenance fertilization with NPK positively affects the recovery of degraded pasture of U. decumbens, promoting increased production and accumulation of forage, and the reform of this pasture with implantation of M. maximus cv. BRS Quênia, promoted greater production and accumulation of forage, in addition to better morphological composition, which best nutritional value of the forage, when compared to other strategies of recovery of degraded pastures of Urochloa decumbens.

BANKING MEMBERS:
Externo à Instituição - CARLOS EUGÊNIO MARTINS - EMBRAPA
Externo ao Programa - 3157825 - ADENILSON JOSE PAIVA
Externo ao Programa - 3058101 - ANDRE MORAIS MOURA
Presidente - 1322816 - CARLOS AUGUSTO BRANDAO DE CARVALHO
Externa à Instituição - VANESSA ZIRONDI LONGHINI - UNESP