Detalhes bibliográficos
| Ano de defesa: |
2020 |
| Autor(a) principal: |
Dias, Fabiane Pereira Machado
 |
| Orientador(a): |
Leandro, Wilson Mozena
|
| Banca de defesa: |
Silva Neto, Carlos de Melo e,
Fernandes, Paulo Marcal,
Brasil, Eliana Paula Fernandes,
Oliveira Júnior, Juarez Patrício de,
Leandro, Wilson Mozena |
| Tipo de documento: |
Tese
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Universidade Federal de Goiás
|
| Programa de Pós-Graduação: |
Programa de Pós-graduação em Agronomia (EA)
|
| Departamento: |
Escola de Agronomia - EA (RG)
|
| País: |
Brasil
|
| Palavras-chave em Português: |
|
| Área do conhecimento CNPq: |
|
| Link de acesso: |
http://repositorio.bc.ufg.br/tede/handle/tede/10502
|
Resumo: |
The expansion of agriculture in the Brazilian Cerrado occurs at the expense of an accelerated process of deforestation. In a scenario in which land use change corresponds to two thirds of the total greenhouse gas emissions, however, it is possible to manage them in order to maintain and/or increase C stocks in the soil in the most different management systems. Assuming that this change in land use causes changes in the natural cycle of nutrients and having organic matter as a key element in maintaining and improving soil structure, considering the productive potential of this important biome, this study sought to understand the mechanisms of inputs and outputs of organic matter in the soil and the dynamics of P in different management systems in the Cerrado region of Goias. The study was carried out at Fazenda Nossa Senhora Aparecida, located in the municipality of Hidrolândia-GO, in a Ferralsol with a sandy loam texture. The following management systems were evaluated: pasture, no-tillage, organic cultivation with different years of management (2, 6, 8 and 10 years) and a conventional production system. In addition, an area under native Cerrado (tropical savanna) was selected and used as a reference for balance in the comparative study. The soil samples were collected at 0.0-0.10; 0.10-0.20 and 0.20-0.40 m in depth, considering four repetitions. The differences between the management systems were evaluated statistically through the analysis of orthogonal contrasts and main components. In the first chapter, chemical attributes and fractions of soil organic matter were evaluated. In the second chapter, the contents and stocks of organic C and the soil C resilience index were analyzed. Finally, in the last chapter, the sequential fractionation of P was performed, obtaining the fractions of organic and inorganic P: P-H2O, P-NaHCO3, P-NaOH, P-HCl and residual P. The results showed that the Cerrado soils are highly dependent on the organic C dynamics of the soil. The conversion of the Cerrado into agricultural land decreases the chemical fertility of the soil, however, alternative systems that reduce soil preparation and increase organic inputs, such as organic cultivation and no-tillage, seem to be suitable options for agricultural activity in the Brazilian Cerrado. We also found that, clearly, agricultural systems that favor organic inputs and reduce soil disturbance are more efficient in recovering P availability in the soil. The conventional preparation promotes high losses of P, including most labile forms of P, associated with low inputs of organic matter and intense soil disturbance. On the other hand, organic farming shows a high potential for P recovery after the change in land use, favoring the predominance of labile and moderately labile P compartments. This positively affects the availability of P in Cerrado soils, where P fixation is one of the main factors attributed to the low exchangeable P content. |
