01602nas a2200169 4500008004100000245010600041210006900147300001300216490000700229520097300236653002201209100001701231700001801248700001901266700001701285856013001302 1989 eng d00aEffects of available P and N:P ratios on non-symbiotic dinitrogen fixation in tallgrass prairie soils0 aEffects of available P and NP ratios on nonsymbiotic dinitrogen a471 -4740 v793 a
Prescribed burning is a major control over element cycles in Tallgrass prairie (Eastern Kansas, USA). In this paper we report potential effects on fire on non-symbiotic 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 soils 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 a N:P via a log-linear relationship. Extrapolation of laboratory results to the field yielded a maximal estimate of 21 kg N ha-1y-1. Results support arguments from the marine and terrestrial literature that P availability is central to regulation of ecosystem N budgets. Key words: Cyanobacteria, fire, acetyline reduction, ash
10atallgrass prairie1 aEisele, K.A.1 aSchimel, D.S.1 aKapustka, L.A.1 aParton, W.J. uhttp://lter.konza.ksu.edu/content/effects-available-p-and-np-ratios-non-symbiotic-dinitrogen-fixation-tallgrass-prairie-soils