Eisele K A, Schimel D S, Kapustka L A, Parton W J
Natural Resource Ecology Laboratory, Colorado State University, 80523, Fort Collins, CO, USA.
Department of Botany, Miami University, 45056, Oxford, OH, USA.
Oecologia. 1989 Jun;79(4):471-474. doi: 10.1007/BF00378663.
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 y. Results support arguments from the marine and terrestrial literature that P availability is central to regulation of ecosystem N budgets.
规定火烧是美国堪萨斯州东部高草草原元素循环的主要控制因素。在本文中，我们报告了火烧对非共生固氮的潜在影响。火烧导致灰烬中有效磷的增加，这可能会刺激陆生蓝细菌的固氮作用。在实验室土壤试验中，蓝细菌的固氮酶活性和生物量对添加的灰烬或磷呈阳性反应。进一步的土壤试验表明，蓝细菌对一系列浓度范围内有效氮与有效磷的比例（aN:P）变化有反应。固氮率可以通过对数线性关系根据经验与aN:P相关。将实验室结果外推到田间得出的最大估计值为21 kg N ha y。结果支持了海洋和陆地文献中的观点，即磷的有效性是生态系统氮预算调节的核心。
