Field Measurement of Beef Pen Manure Methane and Nitrous Oxide Reveals a Surprise for Inventory Calculations

Abstract

Few data exist on direct greenhouse gas emissions from pen manure at beef feedlots. However, emission inventories attempt to account for these emissions. This study used a large chamber to isolate NO and CH emissions from pen manure at two Australian commercial beef feedlots (stocking densities, 13-27 m head) and related these emissions to a range of potential emission control factors, including masses and concentrations of volatile solids, NO, total N, NH, and organic C (OC), and additional factors such as total manure mass, cattle numbers, manure pack depth and density, temperature, and moisture content. Mean measured pen NO emissions were 0.428 kg ha d (95% confidence interval [CI], 0.252-0.691) and 0.00405 kg ha d (95% CI, 0.00114-0.0110) for the northern and southern feedlots, respectively. Mean measured CH emission was 0.236 kg ha d (95% CI, 0.163-0.332) for the northern feedlot and 3.93 kg ha d (95% CI, 2.58-5.81) for the southern feedlot. Nitrous oxide emission increased with density, pH, temperature, and manure mass, whereas negative relationships were evident with moisture and OC. Strong relationships were not evident between NO emission and masses or concentrations of NO or total N in the manure. This is significant because many standard inventory calculation protocols predict NO emissions using the mass of N excreted by the animal.

Nitrous oxide, ammonia and methane from Australian meat chicken houses measured under commercial operating conditions and with mitigation strategies applied

“…These studies suggest that excreted N and residual N remaining in the litter do not adequately explain N 2 O emissions, questioning the implied association between excreted N and N 2 O emissions. Recently, Redding et al (2015) observed no correlation between manure substrate N and N 2 O emissions from beef cattle manure pen surfaces, and similarly questioned the implied association between excreted N and N 2 O. Thus, further process knowledge is required to determine whether N 2 O emissions are similarly governed by factors other than N excretion in meat chicken houses, potentially enabling alternative inventory approaches other than predicting emissions relative to excreted N.…”

Impacts on Productivity through Sustainable Fertilization of Nopal (Opuntia Ficus-Indica) Crops Using Organic Compost

“…GHG emissions may be an important factor in environmental matters, however, the region (Milpa Alta) currently lacks of controls for monitoring the GHG emissions. Nevertheless, studies have been carried out at the global level where the emission of CH 4 generated by manure are estimated in 0.236 kg ha -1 D -1 (with 95% confidence index, 0.163-0.332) and where emissions are reported to increase with manure density, pH, temperature and mass (Redding et al, 2015 On the other hand, the use of solid and liquid compost has positively impacted the profitability in the production of nopal. The use of compost has not only increased yield per soil area (Figure 4), but also reduced costs (Table 7) (cost per kg of solid and liquid compost versus chemical fertilizer and raw manure).…”

Nitrous Oxide from Beef Cattle Manure: Effects of Temperature, Water Addition and Manure Properties on Denitrification and Nitrification

“…Beef cattle feedyards produce nitrous oxide (N 2 O) from manure [1][2][3][4][5][6]. Nitrous oxide is a potent greenhouse gas (GHG) implicated in climate change due to a global warming potential (GWP) of 265-298 carbon dioxide equivalent (CO 2 e).…”

“…Nitrification and denitrification generally occur under differing conditions (i.e., redox status, available substrates, and microbial community structure and activity) but can occur simultaneously or in tandem in complex ecosystems. Despite significant research on feedyard N2O, a few key questions remain: (1) What processes are involved in feedyard N2O production and how are they affected by temperature and rainfall? (2) What is the primary source of N2O within a feedyard pen, i.e., the surface manure or the deeper, more anaerobic manure pack?…”

“…Feedyard N 2 O emissions are highly variable over both space and time [4,5]. This variability has been linked to temperature [2,4,9], H 2 O content [2][3][4]10], and manure characteristics [1,4,[11][12][13]. Unfortunately, the relationships observed between these variables and N 2 O losses have been inconsistent, likely due to differences in manure physicochemical properties and treatment effects among studies.…”