Seedlings from golden delicious apples (Malus domestica Borkh. ‘Smoothee’) were grown in the greenhouse with orchardgrass (Dactylis glomerata L. # DACGL), Kentucky bluegrass (Poa pratensis L. # POAPR), red sorrel (Rumex acetosella L. # RUMAA), and Korean lespedeza (Lespedeza stipulacea L. # LESSL) at four densities and four fertility levels. Orchardgrass and red sorrel inhibited tree growth more than Kentucky bluegrass on a per plant basis. Korean lespedeza inhibition of apple growth was associated with the amount of root nodulation on the Korean lespedeza. Apple shoot dry weight over all fertility levels, ground cover species, and densities was predicted by a regression model based on increase with fertility and decrease with ground cover dry weight. These results indicate that the competitiveness between equal number of ground cover species is due to differences in biomass production. Addition of nitrogen to the system increased nitrogen levels in apples but did not completely overcome apple growth inhibition.
