Agricultural greenhouse gas emissions reduced by agri-environment schemes on improved grassland and grazed by intensive beef cattle
The alteration of land use and management practices under agri-environment schemes may impact agricultural greenhouse gas emissions. Scheme agreements require modifications to, for example, the location of livestock during the winter or stipulate the targeted creation of grass buffer strips to reduce erosion. The following paper reports on the change in net greenhouse gas emissions for agri-environment schemes applicable to intensive beef production, relative to existing land management. A Life-cycle Assessment approach has quantified the net greenhouse gas emissions, either positive or negative, that result from a change in management as stipulated by the agri-environment scheme agreement. Seasonal livestock removal (winter housing) reduced emissions, mainly nitrous oxide from wet and potentially compacted soil, and prevented soil carbon loss, typically by a net -0.1 t CO2eq ha-1 year-1. The method of manure storage during the housing period is potentially key in defining the overall impact. Strategies to mitigate emissions during storage, for example the covering of lagoons, are essential to maximise the value of seasonal livestock removal in reducing greenhouse gas emissions. The creation of grass buffer strips had the greatest potential to reduce emissions overall, particularly when placed adjacent to watercourses to prevent erosion or run-off (-11.6 t CO2eq ha-1 year-1). They require, however, the removal of land from its current management. Careful targeting of these options is critical, to maximise agricultural greenhouse emissions reduction from Environmental Stewardship and to minimise the risk of agricultural production displacement.