Atividade enzimática da microbiota e efeito térmico em solo tropical tratado com compostos orgânicos

Bacteria and fungi are the most active decomposers of organic materials in soil. They directly affect plant nutrient availability, and chemical and physical properties of soils. This investigation aimed at quantifying the effect of several organic materials on microbial activity of a Rhodic Eutrudox. Soil samples were incubated over a period of 91 days with the following organic materials: cattle manure (CM), earthworm humus (HM), and city sewage sludge from Barueri (BA) and Franca (FR). The activities of cellulase, protease and urease enzymes, the soil microbial carbon content (by fumigation-extraction method) and the exothermal effect were evaluated. Experimental design was randomized and arranged as factorial scheme five treatments x seven samplings with five replications. Organic materials promoted oscillations in microbial carbon (mg C g-1 soil), and enzyme activities - cellulase (µg glucose g-1 soil 24 h-1), protease (mg Tyr g-1 soil 2 h-1), urease (mg NH4+-N g-1 soil 2 h-1) - and the total thermal effect (J g-1 soil), in the following decreasing order: (1) CM - 21.47; 655.90; 49.68; 24.55; 477.90; (2) BA - 12.98; 367.70; 32.76; 10.66; 426.29; (3) FR - 11.60; 273.40; 18.77; 19.35; 368.00; (4) HM - 11.77; 261.00; 17.05; 9.02; 202.79; (5) control. Correlations were obtained between microbial carbon and cellulase and protease activities (r = 0.54; p < 0.001), and between the exothermal effect and protease activity (r = 0.34; p < 0.005). Enzyme activity was closely related to soil microorganisms, therefore, reflecting on the total thermal effect.Bactérias e fungos são os organismos mais ativos na decomposição de compostos orgânicos no solo, afetando diretamente a disponibilidade de nutrientes para as plantas e as propriedades químicas e físicas dos solos. Este estudo quantificou o efeito de diversos compostos orgânicos na atividade microbiana de um Latossolo Vermelho Eutroférrico típico. As amostras de solo foram incubadas durante 91 dias sob os tratamentos: esterco bovino (CM), húmus de minhoca (HM), e os lodos de esgoto de Barueri (BA) e Franca (FR). Foram avaliadas as atividades das enzimas celulase, protease e urease, o carbono microbiano do solo (método fumigação-extração) e o efeito exotérmico total. O delineamento experimental foi inteiramente casualizado, em esquema fatorial cinco tratamentos x sete amostragens com 5 repetições. Os compostos orgânicos promoveram oscilações no carbono microbiano (mg C g-1 solo), na atividade das enzimas celulase (µg glicose g-1 solo 24 h-1), protease (mg Tyr g-1 solo 2 h-1) e urease (mg NH4+-N g-1 solo 2 h-1) e no efeito térmico total (J g-1 solo), na seguinte ordem decrescente: (1) CM - 21.47; 655.90; 49.68; 24.55; 477.90; (2) BA - 12.98; 367.70; 32.76; 10.66; 426.29; (3) FR - 11.60; 273.40; 18.77; 19.35; 368.00; (4) HM - 11.77; 261.00; 17.05; 9.02; 202.79; (5) controle. Correlações foram obtidas entre o carbono microbiano e as enzimas celulase e protease (r = 0.54; p < 0.001), e entre o efeito exotérmico e a protease (r = 0.34; p < 0.005). A atividade de enzimas esteve diretamente relacionada à microbiota do solo, refletindo, dessa forma, no efeito térmico total.674680Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Microbial enzymatic activity and thermal effect in a tropical soil treated with organic materials

Bacteria and fungi are the most active decomposers of organic materials in soil. They directly affect plant nutrient availability, and chemical and physical properties of soils. This investigation aimed at quantifying the effect of several organic materials on microbial activity of a Rhodic Eutrudox. Soil samples were incubated over a period of 91 days with the following organic materials: cattle manure (CM), earthworm humus (HM), and city sewage sludge from Barueri (BA) and Franca (FR). The activities of cellulase, protease and urease enzymes, the soil microbial carbon content (by fumigation-extraction method) and the exothermal effect were evaluated. Experimental design was randomized and arranged as factorial scheme five treatments x seven samplings with five replications. Organic materials promoted oscillations in microbial carbon (mg C g-1 soil), and enzyme activities - cellulase (µg glucose g-1 soil 24 h-1), protease (mg Tyr g-1 soil 2 h-1), urease (mg NH4+-N g-1 soil 2 h-1) - and the total thermal effect (J g-1 soil), in the following decreasing order: (1) CM - 21.47; 655.90; 49.68; 24.55; 477.90; (2) BA - 12.98; 367.70; 32.76; 10.66; 426.29; (3) FR - 11.60; 273.40; 18.77; 19.35; 368.00; (4) HM - 11.77; 261.00; 17.05; 9.02; 202.79; (5) control. Correlations were obtained between microbial carbon and cellulase and protease activities (r = 0.54; p < 0.001), and between the exothermal effect and protease activity (r = 0.34; p < 0.005). Enzyme activity was closely related to soil microorganisms, therefore, reflecting on the total thermal effect.Bactérias e fungos são os organismos mais ativos na decomposição de compostos orgânicos no solo, afetando diretamente a disponibilidade de nutrientes para as plantas e as propriedades químicas e físicas dos solos. Este estudo quantificou o efeito de diversos compostos orgânicos na atividade microbiana de um Latossolo Vermelho Eutroférrico típico. As amostras de solo foram incubadas durante 91 dias sob os tratamentos: esterco bovino (CM), húmus de minhoca (HM), e os lodos de esgoto de Barueri (BA) e Franca (FR). Foram avaliadas as atividades das enzimas celulase, protease e urease, o carbono microbiano do solo (método fumigação-extração) e o efeito exotérmico total. O delineamento experimental foi inteiramente casualizado, em esquema fatorial cinco tratamentos x sete amostragens com 5 repetições. Os compostos orgânicos promoveram oscilações no carbono microbiano (mg C g-1 solo), na atividade das enzimas celulase (µg glicose g-1 solo 24 h-1), protease (mg Tyr g-1 solo 2 h-1) e urease (mg NH4+-N g-1 solo 2 h-1) e no efeito térmico total (J g-1 solo), na seguinte ordem decrescente: (1) CM - 21.47; 655.90; 49.68; 24.55; 477.90; (2) BA - 12.98; 367.70; 32.76; 10.66; 426.29; (3) FR - 11.60; 273.40; 18.77; 19.35; 368.00; (4) HM - 11.77; 261.00; 17.05; 9.02; 202.79; (5) controle. Correlações foram obtidas entre o carbono microbiano e as enzimas celulase e protease (r = 0.54; p < 0.001), e entre o efeito exotérmico e a protease (r = 0.34; p < 0.005). A atividade de enzimas esteve diretamente relacionada à microbiota do solo, refletindo, dessa forma, no efeito térmico total

Troca ionica, calorimetria, analise termica e microbiologica aplicadas ao latossolo roxo

Orientador: Claudio AiroldiTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuimicaDoutorad

Enzymatic activity measured by microcalorimetry in soil amended with organic residues

Enzymatic activity is an important property for soil quality evaluation. Two sequences of experiments were carried out in order to evaluate the enzymatic activity in a soil (Rhodic Eutrudox) amended with cattle manure, earthworm casts, or sewage sludges from the municipalities of Barueri and Franca. The activity of commercial enzymes was measured by microcalorimetry in the same soil samples after sterilization. In the first experiment, the enzyme activities of cellulase, protease, and urease were determined in the soil samples during a three month period. In the second sequence of experiments, the thermal effect of the commercial enzymes cellulase, protease, and urease on sterilized soil samples under the same tretaments was monitored for a period of 46 days. The experimental design was randomized and arranged as factorial scheme in five treatments x seven samplings with five replications. The treatment effects were statistically evaluated by one-way analysis of variance. Tukey´s test was used to compare means at p < 0.05. The presence of different sources of organic residues increased the enzymatic activity in the sampling period. Cattle manure induced the highest enzymatic activity, followed by municipal sewage sludge, whereas earthworm casts induced the lowest activity, but differed from control treatment. The thermal effect on the enzyme activity of commercial cellulase, protease, and urease showed a variety of time peaks. These values probably oscillated due to soil physical-chemical factors affecting the enzyme activity on the residues