Addition of Straw or Sawdust to Mitigate Greenhouse Gas Emissions from Slurry Produced by Housed Cattle: A Field Incubation Study

Abstract

The use of housed wintering systems (e.g., barns) associated with dairy cattle farming is increasing in southern New Zealand. Typically, these wintering systems use straw or a woodmix as bedding material. Ammonia (NH) and greenhouse gas (GHG) emissions (nitrous oxide [NO] and methane [CH]) associated with storage of slurry + bedding material from wintering systems is poorly understood. A field incubation study was conducted to determine such emissions from stored slurry where bedding material (straw and sawdust) was added at two rates and stored for 7 mo. During the first 4 mo of storage, compared with untreated slurry, the addition of sawdust significantly reduced NH and CH emissions from 29 to 3% of the initial slurry nitrogen (N) content and from 0.5 to <0.01% of the initial slurry carbon (C) content. However, sawdust enhanced NO emissions to 0.7% of the initial slurry-N content, compared with <0.01% for untreated slurry. Straw generally had an intermediate effect. Extending the storage period to 7 mo increased emissions from all treatments. Ammonia emissions were inversely related to the slurry C:N ratio and total solid (TS) content, and CH emissions were inversely related to slurry TS content. Mitigation of GHG emissions from stored slurry can be achieved by reducing the storage period as much as possible after winter slurry collection, providing ground conditions allow access for land spreading and nutrient inputs match pasture requirements. Although adding bedding material can reduce GHG emissions during storage, increased manure volumes for carting and spreading need to be considered.

Do volatile solids from bedding materials increase greenhouse gas emissions for stored dairy manure?

“…The shift in N-based emissions is also consistent with the lower pH with the wood bedding slurry favouring direct N 2 O emissions over indirect NH 3 -N emission (VanderZaag et al 2010). The lower pH may be associated with the acidic nature of wood shavings (van der Weerden et al 2014), although the acidity of the bedding materials alone was not characterized in this study.…”

Protection from wintertime rainfall reduces nutrient losses and greenhouse gas emissions during the decomposition of poultry and horse manure-based amendments

“…Ultimately, greater nutrient concentrations in poultry amendments result in a larger potential for nutrient losses, especially when exposed to rainfall, although this may be affected by differences in animal physiology and feeding regimes, e.g., between chicken and under-studied poultry amendments such as turkey manure (Moreno-Caselles et al 2002;Nicholson, Chambers, and Smith 1996). Finally, the type of bedding found in amendments may affect nutrient cycling and GHG emissions through changes in particle size and oxygen availability (Monteny, Bannink, and Chadwick 2006;Van der Weerden, Luo, and Dexter 2014).…”

Effects of pH, Total Solids, Temperature and Storage Duration on Gas Emissions from Slurry Storage: A Systematic Review

“…Results showed that these influencing factors (i.e., fixed effects) explained about 51% of variance (marginal R 2 ) and 49% of variance was caused by selected publications (i.e., references) and residual error, of which variance of references accounting for 52%. Among references, measurements of NH 3 -N emissions from studies of Dinuccio et al [19] and van der Weerden et al [10] were relatively higher than measurements from studies of Fangueiro et al [18] and Le Riche et al [23] (Supplemental Figure S1).…”

“…The study of Wood et al [38] reported that NH 3 emissions increased linearly with slurry TS contents varying from 3 to 95 g kg −1 . Van der Weerden et al [10] found the inverse logarithmic relationships between cumulative NH 3 emissions versus the TS contents ranging from 76 to 399 g kg −1 . These results from different studies indicated that the relationship between NH 3 -N emissions and slurry TS contents highly depends on the investigated range of TS contents.…”

“…The independent influence of slurry characteristics, environmental conditions, and management practices on gas emissions from liquid manure storage has been investigated. For example, van der Weerden et al [10,11] demonstrated inverse logarithmic relationships between slurry total solids (TS) contents and NH 3 and CH 4 emissions. Sawamoto et al [12] revealed the effects of temperature and length of storage on CH 4 emissions from dairy slurry storage.…”