Banca de DEFESA: LUIZ ALBERTO DA SILVA RODRIGUES PINTO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : LUIZ ALBERTO DA SILVA RODRIGUES PINTO
DATA : 20/02/2020
HORA: 09:00
LOCAL: Instituto de Agronomia
TÍTULO:

Organic matter and chemical attributes of aggregates in no-tillage areas in the Cerrado mineiro.

PALAVRAS-CHAVES:

Conservationist systems, Organic carbon, Aggregation formation pathways.

PÁGINAS: 123
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Ciência do Solo
ESPECIALIDADE: Gênese, Morfologia e Classificação dos Solos
RESUMO:

Measuring the impact of change in land use and management over time has been evaluated using soil quality indicators. Among them, aggregation (stability, genesis and/or formation pathways) and soil organic matter (SOM) (accumulation, protection and/or origin) stand out, always highlighting the close correlation that exists between them. The present stuy was divided into 2 chapters with different objectives: Chapter I, to evaluate physical and chemical attributes, pathways formation and organic carbon levels and forms in aggregates of areas under direct no till system (SPD), conventional planting system (SPC) and Cerrado area (AC); and Chapter II, to evaluate the different fractions of SOM in psychogenic and biogenic aggregates in areas of SPD with 6 and 18 years of age (SPD6 and SPD18) of installation under different plant cover in the Cerrado of Minas Gerais, Uberaba. In Chapter I, three managed areas (management systems) and a reference area without anthropic action were evaluated, totaling four different sample areas: SPD with 6 years (SPD6), SPD with 18 years (SPD18), SPC with 20 years (SPC20) and a Cerrado area (AC). For Chapter II, two areas managed under SPD with different adoptions times and plant coverings and a reference area were evaluated, configuring seven sample areas: SPD6, millet (SPD6MI); SPD6, brachiaria (SPD6BR); SPD6, crotalaria (SPD6CR); SPD18, millet (SPD18MI); SPD18, brachiaria (SPD18BR); SPD18, crotalaria (SPD18CR); and Cerrado area (AC). In each sample area five pseudopetitions were collected in 0.00-0.05 and 0.05-0.10 m depth entirely randomized delineation. After collection the samples were air-dried and later submitted to screening using a set of 9.7 and 8.0 mm mesh sieves, being selected only the aggregates retained in this interval. In these, the percentage of each type of aggregate was quantified from their identification and separation into physiogenic and biogenic. Subsequently, total organic carbon (TOC) and soil organic matter fractionation (SOM) analyses were performed: chemical (C-FAF, C-FAH and C-FHUM), particle physics (COP and COAM) and densimetric physics (CFLL). Among the management systems, the first chapter concludes that the biogenic aggregates contributed more effectively in the protection and stabilization of MOS, mainly of the most labile fractions (COP and CFLL), reducing their decomposition rates and increasing the potential for soil carbon sequestration. In the second chapter the biogenic aggregation presented higher protection, stabilization and accumulation capacity of both the most labile fractions (COP and CFLL) and the most stable (C-FAH, C-FHUM and COAM) of MOS. The results of MOS among the formation pathways were more influenced by the time of adoption of SPDs and their plant cover, than of the different soil management systems.

MEMBROS DA BANCA:
Presidente - 1060711 - MARCOS GERVASIO PEREIRA
Externa ao Programa - 1412091 - ERICA SOUTO ABREU LIMA
Externo à Instituição - THADEU RODRIGUES DE MELO