Farm-Scale Applicability of Three Covers (Peat, Polystyrene Balls and Synthetic Sheet Roof) to Reduce Ammonia Emissions from Pig Slurry Storage

Abstract

Covering the slurry pit has been shown to be one of the best ways to reduce ammonia emissions (NH 3 ) during manure management. Yet, few studies have been conducted at farm scale. We studied the feasibility of three cover materials (peat, polystyrene balls and synthetic sheet roof) to reduce ammonia (NH 3 ) emissions during on-farm storage of pig slurry. The impact on greenhouse gas emissions, methane (CH 4 ), nitrous oxide (N 2 O) and carbon dioxide (CO 2 ) of covering the slurry pit was also evaluated. Simultaneous field experiments were carried out using two similar pits at a farm with peat and polystyrene ball covers, which allowed direct comparison of the feasibility of the two covers to reduce gas emissions (measured using the dynamic chamber technique). Emissions from the third option (using a synthetic sheet roof) were estimated by measuring the concentrations in the headspace under the cover and the air leakage from the cover with a tracer gas (CO 2 ). Results showed that the polystyrene balls cover reduced emissions of NH 3 during storage by up to 80% whatever the season, but increased potential greenhouse gas emissions by 20% in summer. No consistent reduction was achieved with the peat cover even though some individual results seemed to indicate up to 25% reduction in ammonia emissions; moreover, there was a 30% increase in CH 4 and CO 2 emissions during the storage period. The use of a synthetic sheet roof enabled up to 90% reduction in NH 3 , CH 4 and CO 2 emissions whatever the season.

Guía para la minimización de las emisiones de gases en las granjas porcinas

“…Normalmente, se realizan en materiales plásticos (PVC, poliéster) sobre una estructura portante, elevada sobre la lámina del purín y apoyada en uno o varios mástiles centrales (Aguilar et al, 2010). Su efectividad para reducir el NH 3 puede ser muy elevada ya que si está bien instalada las emisiones se producirán solo por las fugas de aire que puedan existir (Loyon et al, 2016). En cualquier caso, este tipo de cubiertas requieren aberturas de ventilación para evitar la acumulación de CH 4 .…”