Patch-dependent herbage growth drives paddock productivity in a long-term extensive grazing system

In extensive grazing systems selective grazing creates stable mosaic structures consisting of frequently grazed, short patches and rarely grazed, tall patches. The stocking rate determines the share of different patch types on a pasture. In the present experiment biomass production of different patch types (‘short’, ’medium’, ‘tall’) and biomass production of paddocks treated with different stocking rates (‘moderate’, ‘lenient’, ‘very lenient’ – 6, 12, 18 cm target sward height) were analysed. The experiment was conducted on a long-term low-intensity set-stocked cattle pasture. We focused on total annual aboveground net primary productivity (ANPP) and on the temporal distribution of ANPP. We hypothesized that short patches are more productive and biomass growth is distributed more homogeneously throughout the season than in tall patches. Furthermore we assumed that paddocks grazed moderately are more productive and biomass growth is distributed more homogeneously than in more leniently grazed paddocks. The results showed that tall patches were not less productive than short patches, which led to similar ANPP of paddocks. ANPP of short patches and moderately grazed paddocks was distributed most homogeneously throughout the season.