Response of two expansive grasses Calamagrostis epigejos and Arrhenatherum elatius to enhanced nitrogen availability
2007
Holub, P., Academy of Sciences of the Czech Republic, Brno (Czech Republic). Institute of Botany, Department of Ecology
A large increase in density and cover of the tall grasses Calamagrostis epigejos and Arrhenatherum elatius has been observed in short dry acidophilous grasslands in the Podyjí National Park in the last decades. Effect of extra N input on biomass production and the concentration of N and P in plant matter were studied during 2002 and 2003 growing seasons in order to assess and compare whether and how higher N availability can support expansion of these tall grasses. In both studied years, Calamagrostis total biomass reached higher values (1529 and 1184 g square m) than in Arrhenatherum (1227 and 990 g square m), but significant only in 2002. Consequently, significantly higher values of fresh above-ground litter were observed in Calamagrostis (699 in 2002 and 533 g square m in 2003) in comparison with Arrhenatherum (434 and 284 g square m, respectively) at the end of the growing seasons. Contrariwise, both concentrations of N and P were significantly higher in Arrhenatherum peak above-ground biomass (11.6-14.3 mg N per g and 2.3 mg P per g than in Calamagrostis (8.4-10.3 mg N per g and (1.6-1.7 mg P per g). Substantial differences were found between species in resorption of nutrients, mainly P, at the end of the growing seasons. P concentrations in Arrhenatherum fresh litter were twice and three times higher than in Calamagrostis, while N concentrations in Arrhenatherum were higher only by 51-111% than in Calamagrostis. Thus, at the end of the growing season, Calamagrostis probably more effectively retranslocated nutrients (N and mainly P) from above-ground biomass in comparison with Arrhenatherum. Recorded differences between both grasses were similar after N application.
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