Effects of available P and N:P ratios on non-symbiotic dinitrogen fixation in tallgrass prairie soils
- Cite this article as:
- Eisele, K.A., Schimel, D.S., Kapustka, L.A. et al. Oecologia (1989) 79: 471. doi:10.1007/BF00378663
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Prescribed burning is a major control over element cycles in Tallgrass prairie (Eastern Kansas, USA). In this paper we report potential effects of fire on nonsymbiotic nitrogen fixation. Fire resulted in additions of available P in ash, which may stimulate nitrogen fixation by terrestrial cyanobacteria. Cyanobacterial nitrogenase activity and biomass responded positively to additions of ash or P in laboratory assays using soil. Further assays in soil showed that cyanobacteria responded to changes in available N:available P ratio (aN:P) across a range of concentrations. Nitrogen fixation rate could be related empirically to aN:P via a log-linear relationship. Extrapolation of laboratory results to the field yielded a maximal estimate of 21 kg N ha-1 y-1. Results support arguments from the marine and terrestrial literature that P availability is central to regulation of ecosystem N budgets.