Effects of nitrogen addition on nitrogen mineralization and nutrient content of expanding Calamagrostis epigejos in the Podyjí National Park, Czech Republic
2008
Holub, Petr | Záhora, Jaroslav
Effects of extra nitrogen (N) input on biomass production, the concentration of N and phosphorus (P) in plant material, and net N mineralization were studied during three growing seasons in a dry acidophilous grassland dominated by Festuca ovina and in a grassland where the tall grass Calamagrostis epigejos was aggressively expanding. In contrast to dry grassland, the Calamagrostis stand utilized more N due to higher plant and microbial demands for soil mineral N, which could prevent the N losses. Additional N supply resulted in the increased net N mineralization mainly in expanding Calamagrostis. There was no effect of N addition on biomass production of Calamagrostis, while a significant increase of total biomass was observed in Festuca in the dry grassland. This higher production was entirely accounted for by the increase in root dry weight. Concentrations of N in the aboveground biomass increased in both Calamagrostis and Festuca dry grassland as a result of N addition. However, P concentrations in Festuca were reduced, while being enhanced in Calamagrostis. The N : P ratio in aboveground biomass significantly increased in both vegetation types studied following N addition, although reaching higher values in dry grassland than in Calamagrostis. This species compensated enhanced N availability with a higher P uptake as compared to Festuca.
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