Cool Farm Tool - Potato: Model Description and Performance of Four Production Systems

The Cool Farm Tool - Potato (CFT-Potato) is a spreadsheet programme that allows the calculation of the amount of CO2 equivalents that it costs to produce 1 t of potato. The spreadsheet was adapted from an original generic version of the tool, and completed for potato production in diverse production areas in the world applying different levels of technology. The CO2 embedded in chemicals during their production and released from the soil after nitrogen fertilization in the CFT-Potato has been updated to consider more recent products and production methods. Energy costs of the operations in the original version taken from generic data provided by the American Society of Agricultural and Biological Engineers Standard, however, were altered (usually increased) where there was evidence from practical sources that the original figures did not apply. For example, the figure of around 16 l of diesel per ha for potato harvesting in the original version was corrected to 60 l of diesel per ha based on observational data. Figures for typical potato operations such as windrowing were supplied. Irrigation with pumps powered by diesel or electricity from the grid, with a centre pivot, a rain gun, drip irrigation and flooding and energy cost for extracting water from deeper sources were also added. We added data for grading, washing, store loading and unloading, the application of a sprout suppressant and storage with ventilation of ambient air or forced refrigeration. The CFT-Potato can be used by growers to calculate the actual costs of 1 t of potato in terms of kilograms CO2 and explore the repercussion of altered management options. Here the comparison of four potato production systems in the Netherlands is shown: seed potatoes (115 kg CO2/t), table potatoes (77 kg CO2/t), starch potatoes (71 kg CO2/t) and organic potato (82 kg CO2/t). Based on potato dry matter, however, starch potato has the lowest footprint mainly due to the extensive use of pig slurry of which the production and transport CO2 costs are attributed to the pig production chain.