Root mass of differentially defoliated patches on a long-term grazing experiment

Abstract

of nutrients. In low-intensity grazing systems, selective grazing leads to the formation of areas that are more frequently defoliated (short patches) than others (tall patches), which is called patch grazing. The different patch types are supposed to have different aboveground biomass productivities. The stocking rate determines the ratio of short and tall patches on a pasture. In a long-term low-intensity cattle grazing experiment with three different stocking rates (target sward heights: 6 cm (moderate), 12 cm (lenient) and 18 cm (very lenient)), the root and shoot biomass of two different patch types (short and tall) was analysed. Due to frequent defoliation we assumed that the root mass is lower in short patches than in tall patches. In contrast to the assumption, the root mass of tall patches was significantly lower than the root mass in short patches. The adverse effect of frequent defoliation on root mass might have been superimposed by a nutrient effect as the nitrogen availability in tall patches appeared to be higher than in short patches.