Agriculture Reference
In-Depth Information
15
Quantitative Measurements
of Ammonia and Methane Loss
from Livestock
S.M. McGinn*
Agriculture and Agri-Food Canada, Lethbridge,
Alberta, Canada
Introduction
(Smith
et al
., 2007). The sources of livestock
NH
3
and CH
4
emissions considered in this chap-
ter are the CH
4
associated with enteric fermenta-
tion in ruminants, and NH
3
and CH
4
from
livestock manure. Previous reviews of the meas-
urement techniques used in agriculture include
Harper
et al
. (2011), and Makkar and Vercoe
(2007) who focused on
in vivo
CH
4
methane
from ruminants. McGinn (2006) and the
National Research Council (2003) reported on
emission techniques for intensive livestock sys-
tems. Previous reviews of techniques to monitor
NH
3
losses from livestock manure include
McGinn and Janzen (1998) and Shah
et al
.
(2006). Neftel
et al
. (2006) reported on the princi-
ples for detecting greenhouse gas (GHG) concen-
tration (e.g. optical systems) and some emission
techniques with application to agriculture.
The sustainability of agriculture involves a balance
of environmental, social and economic attributes
(Cooprider
et al
., 2011). It follows that a corner-
stone of agricultural sustainability is the environ-
mental impact of farming practices on our air,
land and water. This chapter focuses on the two
major atmospheric pollutants associated with the
livestock industry, ammonia (NH
3
) and methane
(CH
4
), and describes the major measurement
techniques available to quantify their emissions,
as well as reviewing the magnitude of these emis-
sions. This chapter does not include nitrous oxide
emissions from livestock manure; however, most
of the techniques discussed also have application
to nitrous oxide and other gas emissions.
Quantifying NH
3
and CH
4
emissions is fun-
damental to our understanding of the impact of
livestock on air, and the development of best
management practices (BMP) to mitigate these
emissions. The goal of improving the environ-
mental sustainability of the livestock industry
using mitigation strategies will become even
more relevant with the expected expansion of
the livestock industry due to increased demand
for meat and milk by an escalating human popu-
lation estimated to reach 9 billion by 2050
Source and Impact of Ammonia
Ammonia is released as a result of the break-
down of protein in the animal feed by microbes
that produce microbial protein. When an excess
of protein is fed, or when there is a lack of carbo-
hydrates (energy) for microbial growth, the
unused NH
3
is excreted.
