Reducing energy input costs and associated greenhouse gas emissions in cotton

Within highly mechanised agricultural productions systems such as the Australian cotton industry, operational energy inputs represent a significant cost to growers. Through an assessment of seven case study sites, it was shown that the total energy inputs were significantly influenced by the management and operation methods adopted, and ranged from 3.7-15.2 GJ/ha of primary energy, at a cost of $80-310/ha and 275-1404 kg CO2 equivalent/ha greenhouse gas emissions. Among all the farming practices, irrigation water energy use was found to be the highest and was typically 40-60% of total energy costs (wherever water is pumped). Energy use of the harvesting operation was also significant, accounting for 20% of overall direct energy use. If a farmer moves from conventional tillage to minimum tillage, there is a potential saving of around 10% of the fuel used on the farm. Compared with cotton, energy used in the production of other irrigated crops on these farms was generally half of cotton. This was due to less intensive management required for these crops, leading to the lower number of farming operations (passes) carried out (generally about 10, in comparison with 17-18 for cotton) and reduced irrigation requirements