Data/hora: 13/06/2024 05:34:11

Biblioteca(s): | Embrapa Cerrados.
Data corrente: | 16/07/1999
Data da última atualização: | 16/07/1999
Autoria: | RENZ, T. E.; NEUFELDT, H.; AYARZA, M. A.; SILVA, J. E. da; ZECH, W.
Título: | Acid monophosphatase: an indicator of phosphorus mineralization or of microbial activity? a case study from Brazilian cerrados.
Ano de publicação: | 1999
Fonte/Imprenta: | In: THOMAS, R.; AYARZA, M.A., ed. Sustainable land management for the oxisols of the Latin American savannas: dynamics of soil organic matter and indicators of soil quality. Cali: CIAT, 1999.
Páginas: | p.173-186.
Idioma: | Inglês
Conteúdo: | Plant production in the Brazilian savannas, also known as the Cerrados, is limited mainly by low P availability. In tropical soils, rich in sesquioxides, P supply of plants depends heavily on the transformation of organic P by phosphatase enzymes into HPO and H2PO4. We examined two Oxisols-one clayey and one loamy-under different land uses for their potential acid monophophatase activity (PAMA) and potential microbial activity. We measured dimenthyl sulfoxide reduction, pH, total C and N, and NaOH-extractable organic and inorganic P. For all parameters other than pH, values were about twice as high in the clayey as in the loamy soil. Land use was found to strongly affect phosphatase activity, which was reduced by both cropping and reforestation. In the clayey soil, pastures seemed to have a positive effect of continuous cropping to pastures resulted in a rapid recovery of phosphatase activity, microbial activity, and C and N levels. However, it retained high inorganic P (Pi) levels found in fertilizer crops. A comparasion of phosphatase activity with microbial activity, total C and N, and P fractions showed that phosphatase was strongly related to microbial activity in the soil and therefore depended much more on soil organic matter than on soil P levels. We also found that although PAMA is useful for indicating a soil's P mineralization capacity, it does not indicate actual P mineralization rates. However, when combined with findings for microbial activity and Pi, it indicates the level of microbially available P, a lack of which probably implies strong competition between plants and microorganisms for this element.
Thesagro: | Cerrado; Fosfatase Ácida; Fósforo; Oxisol; Solo.
Thesaurus Nal: | acid phosphatase; Ferralsols; phosphorus; soil.
Categoria do assunto: | --
Registro original: | Embrapa Cerrados (CPAC)
Exemplares: | CPAC - (2464-1) - UPC - PL - -- - CRI4998 -  - CRI4998 - DIS