Effect of sowing time on field emergence and growth of South African grassland species

This study investigated seedling emergence in field sowings in terms of rate, and maximum seedling emergence, for twenty one species of forb, grass and geophyte species associated with montane South African grassland communities. Species were sown in early and late spring to compare the effect of sowing date on emergence characteristics and subsequent growth. RGR and mean individual standing biomass were calculated for a 150 day post sowing growth window. Species showed highly significant differences in the time taken to achieve 50% emergence, and species rankings on this basis changed according to the date of sowing. There were large differences in RGR between species that were also reflected in mean standing biomass per individual. The data provide a basis for a preliminary, comparative ecological characterization of these species and an insight into how these species establish and potentially avoid competitive elimination in mixed sowings in restoration ecology or in landscape architecture, in the first growing season. The study also provides some indication on how emergence and growth of individual species might affect recruitment and survival in their habitats.