Species diversity and botanical composition of permanent grassland as a response to different grazing management practices

Abstract

The effects of different levels of grazing utilization (two, three and four grazing cycles per year) and mineral fertilization (nil-fertilization; N 100 P 30 K 60) on the botanical composition of permanent grasslands were studied in the locality of Rapotin (Czech Republic, 332 m a.s.l.) from 2003-2010. The vegetation of the experimental pasture was classified as Cynosurion. It was found that moderate treatment (three grazing cycles per year) without mineral fertilization showed the highest value of diversity index (DI = 6.08), and maximum dominance of legumes (D max = 9.1%), particularly Trifolium repens. The highest dominance of grasses (D max = 77.7%), mainly Dactylis glomerata and Elytrigia repens, was achieved with the fertilized treatment utilized in two grazing cycles per year. Based on RDA results, tested management treatments explained 26% of species composition variability, where effect of number of grazing cycles per year was five-times higher than effect of fertilization. We recommend grassland utilization in three grazing cycles per year as the most suitable way from the objective of both species diversity and botanical composition of pastures in similar site conditions. Pasture fertilization should be more controlled by careful consideration of individual pasture goals, actual nutrient status of the soil and possible environmental risks.