A comparison of root competition and shoot competition between Dactylis glomerata and Holcus lanatus

Abstract Dactylis glomerata and Holcus lanatus were grown together in boxes with either full competition, root competition only, shoot competition only or no competition between them. The boxes were either fertilized (150 kg ha‐1N, 100 kg ha‐1 K, 80 kg ha‐1 P) or not fertilized. The experiment was continued for 13 months, and a total of six cuts were taken. H. lanatus was more competitive than D. glomerata throughout the experiment, though the effect declined after flowering during the second growing season. The effects of root competition were generally much greater than those of shoot competition and tended to increase during the first year. However, the effects of root competition declined, relative to shoot competition, after flowering in the second growing season. Fertilizer applications slightly increased the root competitive ability of H. lanatus relative to D. glomerata but slightly reduced its shoot competitive ability.