Prospecção de enzimas de solo de Cerrado sob plantio de cana-de-açúcar

• Autor(a) principal: Purcena, Luiza Luanna Amorim
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/00130000075cn
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/3999
• topic: Solo; Enzimas; Manejo; Cerrado; Cana-de-açúcar; Soil; Enzymes; Management; Sugarcane; CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

The increasing land area cultivated with sugarcane in Goiás reflects the economic importance of this monoculture not only to Goiás, but also to Brazil. However, the native areas of Cerrado converted to monoculture planting must be monitored since the effects in the biochemical, biological and physicochemical characteristics of soil have already been reported. In this study, the effect of organic (OM) and conventional management (CM) of sugarcane on hidrolases and oxidative enzymes and the results were compared to those for native soil of Cerrado (NS). It was quantified the activity of acid and alkaline phosphomonesterases, β-glucosidases, peroxidases and phenol oxidases. It was also determined the physicochemical parameters such as granulometry (percentage of clay, silt and sand) and content of soil organic matter (SOM), pH, Inorganic phosphorus (P + ), calcium (Ca +2 ), Potassium (K + ). Magnesium (Mg +2 ), Aluminum (Al +3 ), potential acidity total (H+Al) saturation in Aluminum (M%), saturation of alkalis (V%), cation exchangeable capacity (CEC) and the relationship between Ca/CEC, K/CEC and Mg/CEC content as well as the relationships of the cations Ca/K, Ca/Mg, Mg/K,. The optimum pH was assayed for phosphomonoesterases and β-glucosidases. Principal component analyses was performed to identify which factors evaluated would permit to differentiate NS, OM and CM. The results showed the presence of both acid and alkaline phosphomonoesterases in NS, OM and CM; nevertheless, acid phosphomonoesterases were predominant. The optimum pH for acid phosphomonesterase was pH 5.0 and the factors that most interfered on the enzyme activity were pH and granulometry. Sugarcane management did not affect alkaline phosphomonoesterase, in the contrary, acid phosphomonestarase activity was reduced around 50% in the cultivated soils. For β-glucosidase it was observed optimum pH for OM and CM at pH 5.5 and for NS, the enzyme presented higher activity in the pH range from 6.0 to 7.0. β-glucosidase have its activity reduced only in CM, OM and NS presented the same pH profile and similar enzyme activities. pH and granulometry were also the main factors correlated to β-glucosidase activity. Finally, for oxidative enzymes, it was also observed a reduction of enzyme activity in OM and CM in about 57% for peroxidase and 36% for phenol oxidase and pH was the crucial parameter affecting on these enzyme activities.