Rangeland grazing management in Argentine Patagonia

Abstract

Stocking rate adjustment in grazing management is recommended as a management tool to sustain productivity and improve soil health of permanent grassland ecosystems. The aim of this project was to assess the effect of stocking rates under continuous grazing or simple levels of rotational grazing systems on the local environment, when using a moderate or high grazing intensity in the Argentine Patagonia. The parameters investigated were: 1) soil water infiltration and water retention capacity, 2) soil organic matter, N, erosion, and respiration and 3) Plant composition profiles, aboveground net primary production (ANPP), biomass above- and below- ground, physical plant characteristics, and species diversity. In the humid Magellanic grass steppe static rotational grazing was found to increase soil water infiltration rates, N, proportions of forbs and shrubs, root/aerial plant ratio, number of plant species, and proportion of dead plant. Continuous grazing had a greater ANPP, proportion of bare soil, and grasses and graminoids. Under silvopastoral Andean vegetation conditions, rotational grazing resulted in increased root biomass, root/aerial plant ratio, and proportion of forbs compared to continuous grazing, which was found to increase soil organic matter, N, plant length, root depth, aerial plant biomass, soil respiration, proportion of bare soil and dead plants compared to rotational grazing. Intensive grazing negatively influenced soil water, soil and vegetation parameters. The results indicated that adjustment of stocking rate or rotational grazing has a potential to store more biomass than continuous grazing.