Energy use, "food miles" and greenhouse gas emissions from New Zealand dairying - how efficient are we?

Abstract

Assessment of energy use and greenhouse gas emissions associated with dairy products needs to account for the whole life cycle of the products, particularly with the debate about "food miles"(the transportation of product from producer to consumer). A life cycle assessment (LCA) of an average NZ dairy farm for 2005 showed that total energy use per kg milk from the "cradle-tomilk- in-the-vat" was 45-65% of that from EU farms. The greenhouse gas (GHG) emissions or carbon footprint showed similar relative trends although differences were smaller due, at least in part, to lower methane efficiency from lower-producing NZ cows. Energy use associated with shipping dairy product (e.g. cheese) from NZ to UK is equivalent to about one-quarter of the on-farm use. Even when added together, the energy use from the NZ farm and from shipping would still be less than onfarm energy use for the EU farms. However, this is affected by intensification and the Dexcel Resource Efficient Dairying trial showed that increasing maize silage use, and nitrogen fertiliser use in particular, increased the energy use and GHG emissions per kg milk by up to 190% and 23%, respectively. Thus, the trend for intensification on NZ dairy farms means that our comparative advantage with EU farms is diminishing. A focus on improved farm system practices and integration of mitigation options is required to reverse this trend. Keywords: food miles, greenhouse gases, energy, life cycle assessment, milk, New Zealand, efficiency

Biofuels agriculture: landscape‐scale trade‐offs between fuel, economics, carbon, energy, food, and fiber

“…We used values of t CO 2 −e t −1 for i = Wheat ( F ) from simapro 7.2 and t CO 2 −e t −1 for i = Lupins ( F ) assuming lupins are sold as sheep feed [and 1 ton of lupins feeds 2.5 sheep per year (Margan, 1994), and sheep emit 0.1428 t CO 2 −e head −1 yr −1 (Department of Climate Change, 2009)]. For the post‐farm‐gate stages of the product life cycle for i = Grazing ( F ) GHG emissions are considered from both meat and wool products such that where t CO 2 −e head −1 for meat products (Ledgard et al , 2010) and t CO 2 −e kg −1 of wool based on ratios for meat emissions from Ledgard et al (2010). Layers of long‐term average net GHG emissions (positive values represent net GHG emissions in t CO 2 −e ha −1 ) from food agriculture GHG Food , s were created for each scenario s in S by combining the GHG emissions layers for individual land uses i for i = Wheat ( F ), Lupins ( F ), and Grazing ( F ) using the farming system rotation frequencies such that and (see Bryan et al , 2010, in press).…”

“…We calculated net energy layers E i , s (MJ ha −1 yr −1 ) for i = Grazing ( F ) based on a uniform rate for pasture management per unit area ω i (MJ ha −1 yr −1 ), the energy use in post‐farm‐gate stages of the product life cycle (transport, processing) for meat (MJ head −1 ) and wool (MJ kg −1 ), and the energy content of meat products (MJ head −1 ) such that where Q 1 i , s is the grazing productivity, Q 2 i is the wool production rate, and TRN i is the proportion of the sheep herd sold for slaughter as described earlier. We used values of ω i =−457 MJ ha −1 yr −1 (S. Eady, unpublished results), and derived from Ledgard et al (2010), and from Food Standards Australia New Zealand (2006). Long‐term average annual net energy layers for food agriculture E Food , s (MJ ha −1 yr −1 ) were created for each scenario s in S by combining the net energy layers for individual land uses i for i = Wheat ( F ), Lupins ( F ), and Grazing ( F ) using the farming system rotation frequencies such that and (see Bryan et al , 2010, in press).…”

Sustainability of Timor Deer in Captivity: Captive Breeding Systems in West Java, Indonesia

“…The least emissions are produced from pig breeding, ranging from 0.959 to 6.90 kgCO 2 eq (González-García et al., 2015; Nguyen et al., 2011; Rebecca et al., 2013; Reckmann, 2013; Reckmann et al., 2012; Roy et al., 2012; Winkler et al., 2016). For sheep breeding, the GHG impact generated ranges from 19.0 to 28.4 kgCO 2 eq (Ledgard et al., 2010; Ripoll-Bosch et al., 2011). The greatest emissions are produced from cattle breeding, ranging between 13.78 to 35.6 kgCO 2 eq (Florindo et al., 2017; Huerta et al., 2016; Ogino et al., 2016; Pelletier et al., 2010; Rebecca et al., 2013; Roop et al., 2013; Roy et al., 2012).…”

The carbon footprint of UK sheep production: current knowledge and opportunities for reduction in temperate zones

“…On-farm emissions dominate the sheep supply chain carbon footprint up to the point of sale (EBLEX 2012) and even after-export and consumer-stage emissions such as cooking are accounted for (Ledgard et al 2010). Enteric fermentation CH 4 emissions constitute the largest component of on-farm emissions from sheep production (e.g.…”

“…0·57–0·58), followed by N 2 O arising directly from soils in response to nitrogen application as fertilizer or animal waste (e.g. 0·15) (Ledgard et al 2010; Taylor et al 2010).…”