Grazing management for sustainable grazing systems

Abstract, Improving grassland and pasture management in temperate agriculture, 2018

The sustainability of agricultural and livestock systems has been a major challenge for researchers throughout the world. Concerns regarding the impacts of current agronomic and management practices have been raised in many quarters in recent decades. It is evident that limited knowledge of plant–animal–soil interactions has historically generated a number of negative environmental impacts. In grazing systems, those negative impacts can be observed in both intensive and extensive systems, and in both natural and sown pastures.

In the absence of grazing, plant litter is returned to the soil, and organic matter from the decomposing plant tissue accumulates in soil with a spatially homogeneous distribution. A major effect of grazing at the ecosystem level is the decoupling of carbon (C) and nitrogen (N) in plant organic matter, with C respired to the atmosphere as CO2 and CH4, and N returned to the soil via urine in patches of high concentration (Parsons et al., 2011; Soussana and Lemaire, 2014). The issue of decoupling of N and C is further compounded in some grazing systems by the addition of fertiliser N to increase the herbage production.