Extensification of dairy farming and floristic richness of peat grassland.

Abstract

A comparative study of floristic richness of 125 permanent peat grasslands was made in 1983-84 across Zuid-Holland and Utrecht provinces. Three different parameters of floristic richness were used: the number of species, the number of those species that contribute to the conservational value (quality indicating species) and a 'nature value' index that combines species richness with rarity of species. N supply (0-600 kg N/ha per year) was the most important factor determining number of quality-indicating species. Additional factors were peat mud dressing and soil type. Utilization of grassland (whether frequently cut or continuously grazed), ground water table level, pH, P and K contents of the topsoil and type of animal manure had no effect on floristic richness. At levels below 200 kg N/ha per year, a considerable number of species of conservational value (e.g. Lychnis flos-cuculi and Carex nigra) became abundant. The significance of the results for nature conservation with regard to current agricultural practice is discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)