This report is presented in 6 sections

- Feeding concentrates and starch have been proposed to reduce CH4 from ruminants
- However, level of supplement required to reduce CH4 is not known.

The research presented here is a pilot study to investigate the suitability of two novel, independent methods of direct methane assessment in cattle rumens.

In recent years the strategic use of supplementary feeds on New Zealand (NZ) dairy farms has contributed to intensification and increased productivity. Maize silage is the dominant source of NZ produced supplementary feeds on farms, as it provides a low cost source of starch and fibre for dairy cattle (Kolver et al., 2001).

In New Zealand, methane (CH4) contributes 38% and nitrous oxide (N2O) 17% (CO2 equivalents; CO2-e) of the annual emissions (NZ Climate Change Office, 2003). Agriculture contributes about half of New Zealand GHG emissions, most of them coming from grazed pasture-based livestock production systems. In these systems, enteric fermentation and urinary-nitrogen (urinary-N) are the most important sources of CH4 and N2O (Waghorn, 2008).

Economic and policy implications of alternative metrics to account for emissions of non-CO2 greenhouse gases

Hotspot Areas of Nitrous Oxide Emissions from Pasture Grazed by Dairy Cows
SLMACC final report for MPI, May 2016

This final report includes the contracted outputs (manuscripts) from two separate, yet
linked, field studies which have quantified greenhouse gas (GHG) emissions from
managed peat soils including nitrous oxide (N2O) and carbon dioxide (CO2).

IntroductionDicyandiamide (DCD) is a nitrification inhibitor, itselfsusceptible to biodegradation (Ulpiani, 1906; Hauser andHaselwandter, 1990). Based on published data from incuba-tion of soil samples to which DCD had been applied, Kelliheret al. (2008) developed a relationship between time forDCD concentration to halve (t½) and the mean soil temper-ature (T), accounting for 85% of the variability. Under fieldconditions, additional factors might be influential.

This project investigated two novel technologies with the potential to mitigate methane (CH4) emmissions from New Zealand's dairy farms:
1) methane biofilters and
2) a clay-based rumen modifier to reduce methane production in cattle

Biofiltration, through which CH4 is oxidised by methanotrophic bacteria, is a potentially effective strategy for mitigating CH4 emissions from anaerobic dairy effluent lagoons/ponds, which typically do not produce enough biogas for energy recovery. This study reports on the effectiveness of a biofilter cover design for oxidising CH4 produced by dairy effluent ponds.

This project has developed better methods for culturing rumen bacteria, to make them available for more detailed investigation. This research underpins the development of a good fundamental understanding of rumen bacteria, which is a critical step towards manipulation and successful “hydrogen management” as a tool to mitigate rumen methane. The advance was achieved by developing better growth media, and using a statistical approach to rapidly isolate pure cultures of fermentative bacteria. Isolates of new genera of rumen bacteria were obtained that will allow a better understanding of the rumen to be achieved.

There are many studies that project the impacts of climate change, including changes in atmospheric carbon dioxide (CO2), but far fewer that examine the impacts that climate change is already having on our biological systems (Gregory & Marshall 2012).

Previous farm systems modelling to quantify the role of farm management on greenhouse gas (GHG) emissions has identified promising options for reducing emissions from dairy systems. Some of these options have been included in the design of the Pastoral 21 farmlet studies that ran from 2011 to 2015 in Waikato, Manawatu, Canterbury and South Otago.

Farmed animals in New Zealand contribute around 46% of the country’s greenhouse gas output. Of this, approximately 69% is methane (CH4) and 31% is nitrous oxide (N2O), with 80% of the latter resulting from nitrification and denitrification of urinary nitrogen by soil microorganisms and, to a much lesser extent, faecal nitrogen. To date, models evaluating the nitrogen (N) excretion of ruminants have assumed that N excreted in urine is constant and research on mitigating N2O output has largely focussed on nitrification inhibitors such as dicyandiamide (DCD), stand-off pads to keep stock off pastures in wet conditions and feeding low N feeds such as maize silage.

The aim of this study was to assess the potential use of δ13C in a future breeding program for selection of radiata pine genotypes with high water use efficiency (WUE) and better growth performance under drought-prone conditions through quantifying the genetic variation in needle δ13C (a surrogate index of WUE), height and diameter growth of 20 individual trees of 120 open pollinated radiata pine families, and determining the genetic correlations among these traits.