Banca de DEFESA: LUIZ ALBERTO DA SILVA RODRIGUES PINTO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUIZ ALBERTO DA SILVA RODRIGUES PINTO
DATE: 01/04/2024
TIME: 09:00
LOCAL: Sala 24 do Departamento de Solos
TITLE:

Sandy Soils in the Western Region of Paraná: Aggregation and Organic Matter as Quality Indicators

KEY WORDS:

Fragile soils. Production systems. Biogenic aggregates. Sustainable agriculture.

PAGES: 153
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SPECIALTY: Manejo e Conservação do Solo
SUMMARY:

Agricultural production systems with a wide variety of plant species can maintain or improve the quality of soils, especially those with a sandy texture. Monitoring the impact of these forms of use and management can be done by analyzing soil properties that can act as quality indicators. This monitoring makes it possible to assess the changes in soil attributes resulting from the adoption of these agricultural systems and the environmental sustainability that can be promoted by them when they are carried out correctly. The study of the formation pathways (or origins) of aggregates and the attributes associated with aggregation (soil organic matter, SOM) has been used to assess the quality of soils in production areas. This study was divided into three chapters with different objectives: Chapter I verified whether soil use and management affects the proportion of biogenic (Bio) and physicogenic (Phy) aggregates; and whether Bio aggregation promotes improvements compared to Phy aggregation. Chapter II assessed whether Bio aggregation provides greater stabilization of macro- and microaggregates; and whether Bio aggregates are associated with higher levels of labile organic carbon and glomalin. Chapter III aimed to i) quantify the chemical attributes associated with the fertility of Bio and Phy aggregates; and ii) evaluate the total carbon, nitrogen, phosphorus and potassium contents and their respective stoichiometric ratios and the phosphorus fractions with different degrees of lability and availability. Three areas under different production systems and one reference area were evaluated, namely: permanent pasture (PP); no-tillage system (NT); no-tillage system + Brachiaria (NT+B); and a forest fragment in the Atlantic Forest biome (NF). In each sampling area, undeformed samples were collected from the surface layer of a Argissolo Vermelho-Amarelo Distrófico, with a sandy texture in the surface horizons. The samples were air-dried and then sieved using two sets of sieves with mesh sizes of 9.7-8.0 and 8.0-4.0 mm, selecting the aggregates retained in these intervals. The aggregates were separated, identified and classified according to their origin by analyzing their morphology. Chapter I found that the quantity of plant residues was more important than the diversity of species in the formation of Bio aggregates; that the beneficial effect of Brachiaria was observed when adopted in a consortium with maize; and that the Bio aggregates favored higher values of the more labile fractions of SOM, which suggests an improvement in soil quality in the surface layer. Chapter II found that grain production systems, pasture and environments with a low degree of anthropization had a different influence on aggregation and the content of organic fractions associated with aggregate stability. Chapter III found that the chemical attributes of the Bio and Phy aggregates were affected differently between the agricultural production systems; and that the results found for the Bio aggregates reiterate the importance of studying the pathways of formation in assessing the chemical quality of the soil in conservation management areas.

COMMITTEE MEMBERS:
Presidente - 1060711 - MARCOS GERVASIO PEREIRA
Externo ao Programa - 2136627 - NIVALDO SCHULTZ - UFRRJExterno à Instituição - DAVID VILAS BOAS DE CAMPOS - EMBRAPA
Externo à Instituição - FABIANO DE CARVALHO BALIEIRO
Externo à Instituição - JOSE LUIZ RODRIGUES TORRES