Biology and Fertility of Soils

, Volume 24, Issue 4, pp 421–428

Seasonal responses in microbial biomass carbon, phosphorus and sulphur in soils under pasture

Authors

  • Z. L. He
    • Department of Agricultural and Environmental Science, University of Newcastle, Newcastle Upon Tyne, NE1 7RU, UK Tel: (191)222-5677; Fax: (191)222-5677
  • J. Wu
    • Department of Agricultural and Environmental Science, University of Newcastle, Newcastle Upon Tyne, NE1 7RU, UK Tel: (191)222-5677; Fax: (191)222-5677
  • A. G. O‘Donnell
    • Department of Agricultural and Environmental Science, University of Newcastle, Newcastle Upon Tyne, NE1 7RU, UK Tel: (191)222-5677; Fax: (191)222-5677
  • J. K. Syers
    • Department of Agricultural and Environmental Science, University of Newcastle, Newcastle Upon Tyne, NE1 7RU, UK Tel: (191)222-5677; Fax: (191)222-5677
ORIGINAL PAPER

DOI: 10.1007/s003740050267

Cite this article as:
He, Z., Wu, J., O‘Donnell, A. et al. Biol Fertil Soils (1997) 24: 421. doi:10.1007/s003740050267

Abstract

The response of the soil microbial biomass to seasonal changes was investigated in the field under pastures. These studies showed that over a 9-month period, microbial biomass carbon, phosphorus and sulphur (biomass C, P, S), and their ratios (C:P, C:S, and P:S) responded differently to changes in soil moisture and to the input of fresh organic materials. From October to December (1993), when plant residues were largely incorporated into the soils, biomass C and S increased by 150–210%. Biomass P did not increase over this time, having decreased by 22–64% over the dry summer (July to September). There was no obvious correlation between biomass C, P, and S and air temperature. The largest amounts of biomass C and P (2100–2300μg and 150–190μgg–1 soil, respectively) were found in those soils receiving farmyard manure (FYM or FYM+NPK) and P fertilizer, whereas the use of ammonium sulphate decreased biomass C and P. The C:P, C:S, and P:S ratios of the biomass varied considerably (9–276:1; 50–149:1; and 0.3–14:1, respectively) with season and fertilizer regime. This reflected the potential for the biomass to release (when ratios were narrow) or to immobilize (wide ratios) P and S at different times of the year. Thus, seasonal responses in biomass C, P, and S are important in controlling the cycling of C, P, and S in pasture and ultimately in regulating plant availability of P and S. The uptake of P in the pasture was well correlated with the sum of P in the biomass and soil available pools. Thus, the simultaneous measurement of microbial biomass P and available P provide useful information on the potential plant availability of P.

Key words Seasonal responsesMicrobial biomass CMicrobial biomass PMicrobial biomass SNutrient cyclingPasture
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© Springer-Verlag Berlin Heidelberg 1997