Transport and cultivation are also a considerable source and the inputs which go into growing crops comprise another large source. The 'embodied energy' found in fertilisers, especially ammonium and nitrate based fertilisers, can be very large, with around a tonne of oil used to manufacture each tonne of chemical fertiliser. Therefore reducing artificial fertiliser use will increase energy resilience and emissions.
Crop storage and drying
Figures from ADAS show that conventional, high temperature dryers require 55 litres of oil per hectare of crop dried.
Firstly, make sure all controls are set to the right setting, as inappropriate settings can waste up to 25% of the energy used. Humidity is key to crop storage and drying, having the right level could save up to 40% of your energy use due to drying.
Cooling crops rather than drying them could save 10% in like for like comparisons of energy costs.
Good maintenance, ventilation fans at the appropriate size, accurate moisture measurement and aeration together account for a good deal of energy use, so make sure these are all optimised
Mixed flow driers save 50% of energy compared to conventional basic cross-flow driers. Adding recirculation to existing cross-flow driers can save up to 30% of energy usage.
Make sure the dryer is operating at the right capacity, neither too heavily loaded, nor too lightly, which would require a second pass through the drying system.
Finally, make sure you are harvesting at the right time for drying – doing so can reduce the drying time, and therefore associated costs required, by three-quarters.
Minimising energy demands, things to consider
- Can minimium cultivation techniques be used?
- Have you considered growing energy crops?
- Have you considered changing to lower input crops?
- Is each cultivation operation really necessary?
- Do you avoid cultivating in adverse conditions?
- Have you reviewed equipment efficiency?
- Are tractor tyres the correct size and operating pressure?
Make sure that you use the right implement for the job (not the one that is the most fun to drive!)
When purchasing new tractors, check their fuel efficiency and performance data
Do regular maintenance (smoke is not good ....)
Check tyre pressures regularly and determine using manufacturers loading and inflation requirements, and ground conditions and compaction
Maximising work rate and field efficiency can save large amounts of fuel
Consider the use of precision farming and autosteer / GPS
Wider implements will mean a reduced percentage overlap and reduced turning time (although not in small fields)
In cultivation terms, the largest single energy saving step possible is switching to a no-till or minimum-till approach – overall savings of 90% could be possible. This area is covered in more depth in the 'Buildings and operations' and 'Crops' sections.