Managing direct energy use now and in the future

Managing direct energy use now and in the future

[Background and Introduction]:
Agricultural producers are currently aware of increasing energy costs. This has occurred before the scientific and political debate on climate change has been resolved and a decision made on the best policy instruments to be used to respond. In parallel to this discussion, the on farm assessment of direct energy inputs (i.e. diesel and electricity) enables farmers to react positively to the potential of rising energy costs while contributing to a reduction in greenhouse gasses (GHGs) regardless of the scientific and policy debate surrounding climate change and emissions reduction.

Previous work undertaken by the National Centre for Engineering in Agriculture (NCEA) has studied direct on farm energy use involving a number of case study cotton farms to understand the range, costs and contributions of energy use to cotton production and greenhouse gas emissions. The results from this work showed that energy use varies depending on the cropping enterprise and the farming system and that there are significant opportunities to reduce energy and costs. In comparison the greenhouse gas emissions (GHGs) from direct energy use can be similar and in fact greater than the GHGs generated by soil / fertiliser / water interactions. Improving on farm energy use would appear to be as important as improving nitrogen efficiency.

A more detailed study undertaken by the NCEA on a large cotton farm in the Gwydir Valley (reference) identified significant reductions in energy resulting from the adoption of reduced tillage systems. The study showed that the adoption of a minimum tillage system had reduced energy costs (and greenhouse emissions) by 12% since 2000 and developing a 'near zero till' system had the potential to reduce this to 24% less than 2000 energy costs. It is evident from this work that there is substantial scope to improve energy use efficiency in cotton production systems, but to enable more growers to identify where they can improve, further development of tools, processes and human capacity is required.

In the cropping sector a number of practice changes and technology developments have been, or are being, adopted which can be expected to reduce fuel / energy use or energy use intensity. Examples include minimum / zero tillage, controlled traffic, a range of precision ag technologies, planting of GM crops, some water use efficiency measures and use of legumes in crop rotations. Unfortunately, because the primary driver for the adoption of these practices and technologies has not been energy costs or efficiency, relatively few studies have considered the energy savings or efficiencies associated with them.

Within highly mechanised agricultural productions systems such as the Australian Cotton Industry direct energy inputs (i.e. diesel and electricity) represent a major cost to the grower and potentially a significant proportion of the total green house gas (GHG) emissions. Previous studies by Baillie and Chen (2008) have reported significant savings in energy for both a refinement in current practices (i.e. up to 30 % for individual operations) and a change in practice (10 – 20% across the farming system) through energy assessment.

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