Vincent Van Bol

Relationship between aboveground dry weight and N, P and K concentrations in grassland species : A guide for the diagnosis of plant nutrient status

In a field experiment, the dilution curves of 9 grass species and one dicot species, Anthriscus sylvestris, were compared. The P K and Mg contents have been related with aboveground dry weight and N content. The N dilution in the dry matter could be described by only one equation for all species (N = 6 × Y−0.63). The differences between species for P were very small, but Anthriscus sylvestris was always richer than the grasses in K and Mg. The sorting out of the forage samples are thus necessary to determine the nutrient status of these two cations in permanent grasslands. Despite big differences in production, the equations of the nine grass species are very similar for all these nutrients (N, P, K and Mg). The parameters of these equations given here can be used as a guide to determine a satisfactory nutrition.