Methane, nitrous oxide and ammonia emissions from pigs housed on litter and from stockpiling of spent litter

Abstract

Mitigation of agricultural greenhouse gas emissions is a target area for the Australian Government and the pork industry. The present study measured methane (CH4), nitrous oxide (N2O) and ammonia (NH3) from a deep-litter piggery and litter stockpile over two trials in southern New South Wales, to compare emissions from housing pigs on deep litter with those of pigs from conventional housing with uncovered anaerobic effluent-treatment ponds. Emissions were measured using open-path Fourier transform infrared spectrometry, in conjunction with a backward Lagrangian stochastic model. Manure excretion was determined by mass balance and emission factors (EFs) were developed to report emissions relative to volatile solids and nitrogen (N) input. Nitrous oxide emissions per animal unit (1 AU = 500 kg liveweight) from deep-litter sheds were negligible in winter, and 8.4 g/AU.day in summer. Ammonia emissions were 39.1 in winter and 52.2 g/AU.day in summer, while CH4 emissions were 16.1 and 21.6 g/AU.day in winter and summer respectively. Emission factors averaged from summer and winter emissions showed a CH4 conversion factor of 3.6%, an NH3-N EF of 10% and a N2O-N EF of 0.01 kg N2O-N/kg N excreted. For the litter stockpile, the simple average of summer and winter showed an EF for NH3-N of 14%, and a N2O-N EF of 0.02 kg N2O-N/kg-N of spent litter added to the stockpile. We observed a 66% and 80% decrease in emissions from the manure excreted in litter-based housing with litter stockpiling or without litter stockpiling, compared with conventional housing with an uncovered anaerobic effluent-treatment pond. This provides a sound basis for mitigation strategies that utilise litter-based housing as an alternative to conventional housing with uncovered anaerobic effluent-treatment ponds.

Vehicle Ammonia Emissions Measured in An Urban Environment in Sydney, Australia, Using Open Path Fourier Transform Infra-Red Spectroscopy

“…The OP-FTIR system continuously measures the mole-fraction of infrared active gases, including CO, CO 2 , CH 4 and NH 3 , between the spectrometer and the distant retroreflector, which define the ends of the measurement path. The OP-FTIR has previously been used extensively to measure gaseous emissions (CO, N 2 O, NH 3 and CH 4 ) from agricultural systems [31][32][33][34][35][36][37], simulated leaks from coal-seam gas wells [38] and emissions from vegetation fires [39,40].…”

Understanding Spatial Variability of Air Quality in Sydney: Part 1—A Suburban Balcony Case Study

“…The WASPSS-Auburn campaign incorporated a mobile air quality monitoring station and an open-path infrared Fourier transform spectrometer (OP-FTIR). The OP-FTIR system, which can measure infrared active gases such as CO, NH 3 , N 2 O and CH 4 , has previously been deployed for agricultural [28][29][30] and biomass burning [31,32] emissions estimates. Details of the main findings from the OP-FTIR during WASPSS, which relate to vehicle ammonia emissions and episodes of significant smoke pollution, are presented in two separate papers [33,34].…”

Nitrous Oxide Release from Poultry and Pig Housing

“…The main factors for gas emissions of deep litter pig manure are the initial bulk density of the manure, influencing the free air space and gas exchange, and initial carbon and nitrogen contents [79]. Nitrous oxide emissions per animal unit from deep-litter sheds were negligible in winter and 8.4 g.LU.d -1 in summer [85]. With deep litter systems, N 2 O emissions increase regularly in the course of time, principally thanks to the accumulation of dejection and compaction [86][87].…”