Microbial activity and biomass in soil

Principles and Methodologies of Measuring Microbial Activity and Biomass in Soil... 

NANNIPIERI P., PEDRAZZINI F., ARCARA P.G. and PIOVANELLI C. 1979. Changes in amino acids, enzyme activities, and biomasses during soil microbial growth. Soil Science, 127, 26-34. 

Changes in amino acids, enzyme activities and biomasses during soil microbial growth. Soil Science, 127, 26-34. 

We define microbial turnover of phosphorus in soil as the sum of all microbially mediated transformations and the related fluxes of phosphorus in the soil. The quantitative description found in the literature only encompasses the phosphorus flux through the soil microbial biomass (i.e. turnover of microbial phosphorus), and thus excludes phosphorus fluxes to the cell externally caused by microbial activity, indicated by the by-passing arrows in Fig. 7.1 ... 

Fungi, which are active in upland environments, cease to exist in wetland soils. This is primarily due to the absence of oxygen and alteration in soil pH (acid to neutral) under anaerobic conditions. Overall, microbial biomass decreases under saturated soil conditions. The metabolic activities of anaerobic bacteria depend on alternate electron acceptors, such as oxidized forms of nitrogen, iron, manganese, and sulfur. Under wetland soil conditions, rates of many microbially mediated reactions decline, and some reactions may be eliminated and replaced by new ones. New microbial reactions are involved in the reduction of oxidized compounds during respiratory processes, resulting in the production of reduced compounds. 

Zaman, M., H. J. Di, K. C. Cameron, and C. M. Frampton. 1999. Gross nitrogen mineralization and nitrification rates and their relationships to enzyme activities and the soil microbial biomass in soils treated with dairy shed effluent and ammonium fertilizer at different water potentials. Biol. Fertil. Soils. 29 178-186. 

The diverse activity of the biomass in soil organic matter studies integrates with many topics covered in other parts of this book. The reader is, therefore, referred to the appropriate chapters for further information on rates of decomposition and turnover, microbial polysaccharide and soil structure, phytotoxic compounds, enzyme activities, and mineral cycling. 

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