Manure management for greenhouse gas mitigation

Abstract

Ongoing intensification and specialisation of livestock production lead to increasing volumes of manure to be managed, which are a source of the greenhouse gases (GHGs) methane (CH 4 ) and nitrous oxide (N 2 O). Net emissions of CH 4 and N 2 O result from a multitude of microbial activities in the manure environment. Their relative importance depends not only on manure composition and local management practices with respect to treatment, storage and field application, but also on ambient climatic conditions. The diversity of livestock production systems, and their associated manure management, is discussed on the basis of four regional cases (Sub-Saharan Africa, Southeast Asia, China and Europe) with increasing levels of intensification and priorities with respect to nutrient management and environmental regulation. GHG mitigation options for production systems based on solid and liquid manure management are then presented, and potentials for positive and negative interactions between pollutants, and between management practices, are discussed. The diversity of manure properties and environmental conditions necessitate a modelling approach for improving estimates of GHG emissions, and for predicting effects of management changes for GHG mitigation, and requirements for such a model are discussed. Finally, we briefly discuss drivers for, and barriers against, introduction of GHG mitigation measures for livestock production. There is no conflict between efforts to improve food and feed production, and efforts to reduce GHG emissions from manure management. Growth in livestock populations are projected to occur mainly in intensive production systems where, for this and other reasons, the largest potentials for GHG mitigation may be found.Keywords: methane, nitrous oxide, storage, treatment, farm model ImplicationsLivestock manure is a source of greenhouse gas (GHG) emissions, mainly as methane and nitrous oxide. GHG emissions are biogenic and regulated by manure characteristics, and therefore emissions can be manipulated via handling, treatment and storage conditions. Globally, livestock production systems vary widely, and this is also true for GHG mitigation potentials, but generally efforts to conserve nutrients in manure for crop production will also reduce GHG emissions. Future growth in livestock production is projected to occur mainly in confined animal feeding operations, which also appear to have the greatest potential for GHG mitigation. IntroductionSince the mid 20th century, there has been a growing pressure on land resources for production of food and feed for livestock and, increasingly, crops for energy production (Hoogwijk et al., 2005). To fulfil the demand for meat, milk and eggs, livestock production in developing countries is expanding, especially in peri-urban areas (Gerber et al., 2005), and worldwide becomes more specialised (Steinfeld et al., 2006). In consequence of these trends, increasing volumes of livestock manure are produced, which are a source of greenhouse gases (GHGs) contributing t...

Low degradable protein supply to increase nitrogen efficiency in lactating dairy cows and reduce environmental impacts at barn level

“…Reduced gas formation at animal or manure level in the barn might be partially compensated by increased gaseous emissions from manure in the following step of manure management (Dijkstra et al, 2011). In the future, more attention should be given to GHG and ammonia mitigation options at farm level to account for effects on C and/or N flows and associated gas emissions, considering all possible interactions at every stage of the manure management continuum (Petersen et al, 2013).…”

“…This ammonium may then volatilise in the form of ammonia depending on temperature and air velocity. Alternatively, it may be oxidised into nitrites and nitrates through a two-step nitrification process, leading to emissions of intermediate compounds such as nitric oxides (NO x ) and nitrous oxide (N 2 O; Petersen et al, 2013). Reducing nitrogen excretion hence appears critical to reduce environmental impacts.…”

Editorial: Greenhouse Gases and Animal Agriculture Conference, Dublin, 2013

“…Cederberg et al (2013) reviewed the recent development and standardisation of methodologies for life cycle analysis and identified gaps in information about soil C and N fluxes, as well as a lack of studies at the farm level, particularly in developing countries. These same information gaps were identified by del Prado et al (2013) after reviewing farm-scale modelling work on GHG emissions. Although it is hoped that GGAA 2013 will fill some of these gaps, it is also evident from the range of papers submitted that there is still relatively more work on methane emissions and in developed countries and relatively less work on emissions from soils and manure and from developing countries.…”

“…Dijkstra et al (2013) provided an overview of the effects of diet on the level and form of Nitrogen in urine and explored implications for nitrous oxide emissions. Petersen et al (2013) provided an update on techniques for mitigating GHG emissions from manuresboth during storage, as well as during and after application. Two papers in the soil/manure sessions covered technologies outside the usual range of animal, manure and soil managements.…”

“…del Prado et al (2013) provided an overview of modelling in the GHG area and provided new insights by making comparisons between models and considering potential to make links between different GHG models and other physical and economic models. Wheeler et al (2013) described the use of the OVERSEER model to produce farmspecific estimates of emissions per unit product for New Zealand individual farms, while Murphy et al (2013) described the development of the CARBON NAVIGATOR as a knowledge transfer tool to guide farmers and advisers in reducing emissions from Irish dairy and beef herds.…”