Effect of compost-based substrates on growth and leaf physiology of Acer campestre and Cornus alba potted plants

To verify the effects of compost-based substrates on plant biomass production and leaf gas exchanges, 200 uniform, rooted cuttings of Cornus alba 'Elegantissima' and 200 of Acer campestre 'Elsrijk' were potted in 3-1 containers using three different media (in volume). Treatments included: a) compost 1 (20% peat moss, 40% of composted yardwaste, 40% of pumice); b) compost 2 (40% peat moss, 30% of composted yardwaste, 30% pumice); c) compost 3 (40% peat moss, 20% of raw fiber, 40% pumice); 4) control (60% peat moss, 40% pumice). The effect of the different substrates was species-specific. No differences were found in terms of biomass production after two years of cultivation in both species, while some differences were found in the first year with plants grown in uncomposted raw-fiber showing less growth. Leaf gas exchanges were not influenced in Acer campestre plants in the first year, while in the second year, substrate 3 showed lower Pn and evaporation rate. No appreciable differences were detected in Cornus plants. The study shows that it is possible to use compost-based substrates in container nursery production without negative effects on plant biomass accumulation and leaf gas exchanges.