Biology and Fertility of Soils

, Volume 28, Issue 3, pp 244–252

Phosphorus mineralization and microbial biomass in a Florida Spodosol: effects of water potential, temperature and fertilizer application

  • P. F. Grierson
  • N. B. Comerford
  • E. J. Jokela
ORIGINAL PAPER

DOI: 10.1007/s003740050489

Cite this article as:
Grierson, P., Comerford, N. & Jokela, E. Biol Fertil Soils (1999) 28: 244. doi:10.1007/s003740050489

Abstract

 Phosphorus mineralization and microbial biomass were measured in the surface 5 cm of a Spodosol (sandy, siliceous hyperthermic Ultic Alaquod) from north-central Florida. Soils from fertilized and unfertilized plantations of loblolly pine (Pinus taeda L.) were incubated at a range of water potentials (∼0, –3, –8, –10 and –1500 kPa) and temperatures (15  °C, 25  °C and 38  °C) for 14 days and 42 days. Increasing water potential and temperature increased specific P mineralization (mineralization expressed as a percentage of total P) regardless of fertilizer treatment. An increase in water potential from –10 kPa to –0.1 kPa resulted in an increase of between 38% and 239% in the concentration of KCl-extractable inorganic P, depending on incubation temperature and time. An increase in incubation temperature from 15  °C to 38  °C resulted in an increase of between 13% and 53% in KCl-extractable inorganic P. Changes in specific P mineralization with change in water potential or temperature were not affected by fertilizer application. This suggests that, although specific P mineralization was greater in the fertilized soils, environmental control of P mineralization was the same for both treatments. Specific P mineralization was most sensitive when soils were at higher water potentials, and decreased logarithmically to water potentials of between –3 kPa and –8 kPa. Specific P mineralization was relatively insensitive to changes in water potential when water potential was lower than –8 kPa. Microbial biomass C showed no consistent responses to changes of temperature or water potential and was not significantly correlated with specific P mineralization. Our results suggest that field estimates of P mineralization in these Spodosols may be improved by accounting for changes in soil water potential and temperature.

Key words Phosphorus mineralization Microbial biomass C Water potential Temperature Spodosol 

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • P. F. Grierson
    • 1
  • N. B. Comerford
    • 2
  • E. J. Jokela
    • 1
  1. 1.School of Forest Resources and Conservation, 118 Newings-Ziegler Hall, University of Florida, Gainesville, FL 32611-0303, USAUS
  2. 2.Department of Soil and Water Science, 2169 McCarty Hall, University of Florida, Gainesville, FL 32611-0303, USAUS