Nitrogen recycling for the sustainability of Irish agriculture

Livestock farms in the United Kingdom and Ireland are beginning to utilize out-wintering pads (OWPs) made of timber chippings as a cost-effective method of keeping cattle off grazing land during winter. Use of OWPs generates spent timber residue (timber and manure) and effluent (rain water and urine) that must be disposed of after each winter. Nutrients are retained in the spent timber residue (STR) and effluent and can be recycled within the farm system. Nitrogen (N) loss from agricultural systems is a significant source of nutrient pollution to waterways and the atmosphere. Therefore, OWPs require evaluation in terms of N recycling within the farm system to ensure N loss is minimized. This dissertation employed field experiments and modelling to determine whether land application of OWP materials (STR and effluent) is an appropriate waste management strategy for the sustainability of Irish agriculture.