Analysis of the 2007/8 Defra Farm Business Survey Energy Module
The Farm Business Survey (FBS) in the south west is part of the Rural Business School at Duchy College, and forms part of the Rural Business Research (RBR), an independant consortium made up of six university/college research centres across England.
The FBS is conducted on behalf of the Department for Environment, Food and Rural Affairs (Defra) and supported by the farming unions. It has become the most authoritative source of information on the economics of farm businesses in England since it began in 1936.
- The study has delivered an invaluable baseline estimate of energy use and greenhouse gas (GHG) emissions on commercial farms in England. Energy use and GHG emissions associated with particular commodities were quantified and results broadly agreed with those derived by Life Cycle Assessment (LCA), but with much scatter in the environmental performance of farms.
- Direct energy use on farms was generally less that indirect (embedded) energy use, except for horticulture, which is dominated by heating fuel use. In contrast, most GHG emissions are incurred on farms, rather than as embedded emissions.
- Scatter in both environmental and economic performance underlies the somewhat disappointing finding of no clear positive link between farm financial performance and energy use or GHG emissions. However, the mere existence of these ranges shows that there is scope for improvement in both financial and environmental performance and that there is no apparent barrier for both to be achievable in harmony.
- The recording of such farm-level energy data is essential for the future, as it should enable improvements to be made in efficiency of energy use. The improved UK agricultural GHG inventory will depend on high quality energy data on agricultural activities. This study will be invaluable in identifying the level of detail needed.
- The study used a sample of 511 farms in the 2007/08 Farm Business Survey in England.
- Quantities of energy used on farm were recorded, both in direct form, e.g. diesel, electricity, and as embedded energy in materials such as fertilisers and feeds. These data and other factors were used to calculate GHG emissions from farms.
- The study used the Life Cycle approach – with the bought-in items, the energy use values and the GHG emissions including activities pre-farm gate, e.g. extraction, refining and distribution, as well as emissions from on-farm use. Values for embedded energy and GHG emissions came mainly from previous research, but some new inventory values were derived in the study, such as for contractor operations, wood grown on farms, and for some fertiliser types.
- GHG emissions mainly comprised: CO2 from fuel, CH4 from enteric emissions, CH4 and N2O from manure storage, N2O from applications of fertiliser and manure to land, plus excretory returns from grazing livestock and leaching following grassland cultivation.
Finding: Energy and emissions per hectare
- There was, in general, a strong linear relationship across farm types between energy use per hectare and GHG emissions per hectare. This means it is possible to produce quick estimates of GHG emissions form energy data that are relatively easy to derive.
Farm type and size
- Energy use per hectare varied considerably across farm types and sizes. Highest users were specialist poultry farms, lowest were grazing farms in less favoured areas (LFA).
- GHG emissions per hectare followed broadly that same farm type trend as energy usage, but enteric CH4 and field emissions of N2O meant that grazing farms (LFA or lowland) tended to emit more GHG per hectare than general cropping and specialist cereal farms.
- For energy use and GHG emissions per hectare, farm size had much less impact than farm type.
- There was no overall significant difference between organic and non-organic farms on energy use per hectare or GHG emissions per hectare. The only exceptions were organic poultry and organic horticultural farms, where organic had significantly lower values in both cases.
Direct and indirect sources
- Apart from horticultural farms, energy use of most farm types was mainly indirect (i.e. embedded in inputs). This highlights the need to consider both types of energy use. GHG emissions were dominated by on-farm emissions, except on poultry farms.
Soil and biomass carbon: Effects of grassland cultivation and establishment, and woodland
- For most farms the effects of grassland cultivation, establishment and woodlands were relatively small, but the data only allowed a snapshot and may not be wholly representative over a longer time scale as the effects of land use change are long lasting.
- Total losses of soil C via grassland cultivation tended to outweigh gains from grassland establishment. Woodlands provided a net increase in soil C.
Economic and environmental performance
- An approach of using farm economic data to allocate energy use and GHG emissions to commodities was successful for most commodities. It gave results that were generally close to those obtained from LCA studies.
- There was a significant positive link between energy use per farm and income per farm, via higher total energy use on larger farms, which often have higher incomes. But there was no significant relationship on a per hectare basis between income, energy and GHG emissions.
- Beneath the whole farm level, for any commodity or commodity group, there was no reliable significant relationship between gross margin and energy use or emissions. This is undeniably both somewhat surprising and disappointing.
- There was a wide range of both economic and environmental performance in the farms studied. There may be many reasons for the variations, such as soil, rainfall, topography, degree of capitalisation, machinery age or use of contractors. Also this analysis is a snapshot of one farming year.
- More detail is needed to understand the variation in economic and environmental performance across farms and across years. Within the commodities, milk was scrutinised in more detail. There was a weak relationship between energy use of GHG emissions per litre and Net income per litre, and the slope was negative, as desired, albeit influenced by an outlier. However, the significant, although weak, negative slope for milk production and energy does accord with reports of increased profitability and environmental performance in dairying.