Ciclos biogeoquímicos como subsídio para a sustentabilidade do sistema agroindustrial da cana-de açúcar
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Data
2007-06-01
Autores
Barbosa, Valmir [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O crescimento da cultura da cana-de-açúcar, frente à demanda global por energia renovável, provoca preocupações quanto à sua sustentabilidade. Nesse contexto, o objetivo deste trabalho é oferecer uma visão sistêmica do processo agroindustrial da cana-de-açúcar, do ponto de vista dos ciclos biogeoquímicos com a reciclagem de resíduos e efluentes. Para o desenvolvimento do trabalho foram elaborados modelos conceituais e numéricos, apresentando conceitos de ruptura e regeneração de ciclos, sustentabilidade cruzada, equação de configuração do canavial e coeficiente de uso cultural da terra. Foi elaborado um modelo das vias e de estratégias de uso de resíduos e efluentes para N, P, K, Ca, Mg e S, nos diversos compartimentos do processo de produção. Fez-se uma abordagem sobre metais pesados. Foram formulados e discutidos alguns indicadores: índice de adubação (IA), índice de retorno (IR) e índice de emissão (IE), que permitiram uma análise da circulação de nutrientes e da sustentabilidade. No cenário analisado para validação do modelo, concluiu-se que as quantidades de potássio, cálcio e magnésio em circulação foram suficientes para a adubação da cultura, enquanto o nitrogênio, fósforo e enxofre emitidos foram insuficientes, exigindo adubações complementares. Concluiu-se que a moderna agroindústria da cana-de-açúcar apresenta-se conceitualmente muito favorável à sustentabilidade, e ainda exige melhorias para a efetividade desses conceitos. A verticalização da produção, mesmo em monocultivo, pode contribuir para o estabelecimento de um equilíbrio de manejo favorável à sustentabilidade.
The expansion of the sugarcane culture, up against global demand for renewable energy, provokes concerns as for its sustainability. In this context, the objective of this work was to offer a systemic view of the sugarcane agro-industrial process, from the point of view of the biogeochemical cycles with the effluent and residues recycling. For the development of the work conceptual and numerical models were elaborated, showing concepts of rupture and regeneration of cycles, crossed sustainability, cane field configuration equation and cultural land use coefficient. A model of the logistics and use strategies of effluent and residues for N, P, K, Ca, Mg and S was elaborated, in the several compartments of the production process. An approach about heavy metals was made. Some indicators were formulated and discussed: fertilization index (IA), return index (IR) and emission index (IE), which allowed an analysis of the sustainability and nutrients circulation. In the scenario analyzed for the model validation, it was concluded, one concludes that the amount of potassium, calcium and magnesium in circulation were sufficient for the fertilization of the culture, while the nitrogen, phosphorus and sulfur emitted were insufficient, requiring complementary fertilizations. It was concluded that the modern sugarcane agro-industry is conceptually very favorable to the sustainability, and still demands improvements for the effectiveness of these concepts. The verticalization of the production, even in monoculture, can contribute to the establishment of a handling balance favorable to the sustainability.
The expansion of the sugarcane culture, up against global demand for renewable energy, provokes concerns as for its sustainability. In this context, the objective of this work was to offer a systemic view of the sugarcane agro-industrial process, from the point of view of the biogeochemical cycles with the effluent and residues recycling. For the development of the work conceptual and numerical models were elaborated, showing concepts of rupture and regeneration of cycles, crossed sustainability, cane field configuration equation and cultural land use coefficient. A model of the logistics and use strategies of effluent and residues for N, P, K, Ca, Mg and S was elaborated, in the several compartments of the production process. An approach about heavy metals was made. Some indicators were formulated and discussed: fertilization index (IA), return index (IR) and emission index (IE), which allowed an analysis of the sustainability and nutrients circulation. In the scenario analyzed for the model validation, it was concluded, one concludes that the amount of potassium, calcium and magnesium in circulation were sufficient for the fertilization of the culture, while the nitrogen, phosphorus and sulfur emitted were insufficient, requiring complementary fertilizations. It was concluded that the modern sugarcane agro-industry is conceptually very favorable to the sustainability, and still demands improvements for the effectiveness of these concepts. The verticalization of the production, even in monoculture, can contribute to the establishment of a handling balance favorable to the sustainability.
Descrição
Palavras-chave
Sugarcane, Vinasse, Residues, Agro-ecosystem, Modeling, Cana-de-açúcar, Vinhaça, Resíduo, Agroecossistema, Modelagem
Como citar
BARBOSA, Valmir. Ciclos biogeoquímicos como subsídio para a sustentabilidade do sistema agroindustrial da cana-de açúcar. 2007. xi, 117 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2007.