Rhizome growth of Calamagrostis canadensis in response to soil nutrients and bulk density

In a series of experiments, we investigated rhizome spread and the growth of C. canadensis, as governed by changes in soil bulk density and nutrient availability. The ability of rhizomes originating from vigorous Calamagrostis canadensis plants to penetrate mineral soil with different bulk densities and their response to various nutrient conditions were assessed in a split container experiment. Decreasing biomass and length of rhizomes with increasing soil bulk density showed that clonal expansion of C. canadensis onto areas of exposed mineral soil from adjacent swards was limited mainly by soil bulk density. No nutrient effect on rhizome growth was detectable; the rhizomes were probably well supplied with nutrients by translocation from the mother plant. Results of a second split container experiment indicated that rhizome growth was better in organic than in mineral soils. In a third experiment, entire C. canadensis plants were grown in mineral soil at different levels of soil bulk density and nutrient condition. Here, rhizome biomass and expansion were limited mainly by nutrient availability; however, once the nutritional needs of the plants were met, increasing bulk density reduced the amount of rhizome spread. These results could be useful in reforestation, e.g. selecting those methods of site preparation which reduce the growth and competitive ability of C. canadensis relative to tree seedlings. Key words: Compaction, rhizome, litter, mineral soil, yield, Calamagrostis canadensis