RHIZOME GROWTH OF CALAMAGROSTIS-CANADENSIS IN RESPONSE TO SOIL NUTRIENTS AND BULK-DENSITY

In a series of experiments, we investigated rhizome spread and the gro wth of C. canadensis, as governed by changes in soil bulk density and nutrient availability. The ability of rhizomes originating from vigoro us Calamagrostis canadensis plants to penetrate mineral soil with diff erent 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 clon al expansion of C. canadensis onto areas of exposed mineral soil from adjacent swards was limited mainly by soil bulk density. No nutrient e ffect on rhizome growth was detectable; the rhizomes were probably wel l supplied with nutrients by translocation from the mother plant. Resu lts of a second split container experiment indicated that rhizome grow th was better in organic than in mineral soils. In a third experiment, entire C. canadensis plants were grown in mineral soil at different l evels of soil bulk density and nutrient condition. Here,rhizome biomas s and expansion were limited mainly by nutrient availability; however, once the nutritional needs of the plants were met, increasing bulk de nsity reduced the amount of rhizome spread. These results could be use ful in reforestation, e.g. selecting those methods of site preparation which reduce the growth and competitive ability of C. canadensis rela tive to tree seedlings.