6 research outputs found
Impacts of soil moisture level and organic matter content on growth of two Juncus species and Poa pratensis grown under acid soil conditions
The abundance of Juncus effusus (soft rush) and Juncus conglomeratus (compact rush) has increased in coastal grasslands in Norway over recent decades, and their spread has coincided with increased precipitation in the region. Especially in waterâsaturated, peaty soils, it appears from field observations that productive grasses cannot compete effectively with such rapidly growing rush plants. In autumnâwinters of 2012â2013 and 2013â2014, a fourâfactor, randomised block greenhouse experiment was performed to investigate the effect of different soil moisture regimes and organic matter contents on competition between these rush species and smooth meadowâgrass (Poa pratensis). The rush species were grown in monoculture and in competition with the meadowâgrass, using the equivalent of full and half the recommended seed rate for the latter. After about three months, aboveâ and belowâground dry matter was measured. J. effusus had more vigorous growth, producing on average 23â40% greater biomass in both fractions than J. conglomeratus. The competitive ability of both rush species declined with decreasing soil moisture; at the lowest levels of soil moisture, growth reductions were up to 93% in J. conglomeratus and 74% in J. effusus. Increasing water level in peatâsand mixture decreased competivitiveness of meadowâgrass, while pure peat, when moist, completely impeded its belowâground development. These results show that control of rush plants through management may only be achieved if basic soil limitations have been resolved.publishedVersio