Degradation of Forestry Timber Residue Over One Growing Season Following Application to Grassland in Ireland

Out-wintering pads are an outdoor wintering system for cattle built by placing a layer of timber residue over an artificially drained surface. The liquid excreta and rainwater drain from the pad, while the timber residue traps the solid excreta to control solid and liquid wastes from animal confinement. In Ireland, land application represents a pragmatic management strategy for spent timber residue (timber soiled with livestock manure). However, there are no published data on the rates of decomposition of timber residue following application to grassland. This six-month study quantified the temporal trends in sward cover following applications of timber residues (without manure) at three rates (3, 9 and 15 t ha-1) to grassland managed for silage production. While timber in litter bags did not decompose over one growing season, a decrease in timber sward coverage was found independent of application rates of 3 to 15 t ha-1. The data showed from 12 to 26% of timber residue were incorporated into soil on Irish grassland over one growing season.