Low nitrous oxides emissions from Australian processing tomato crops - a win for the environment, our health and farm productivity

摘要

Nitrous oxide is a potent greenhouse gas. It can also increase ultraviolet radiation transmission and incidence of skin cancers by depleting the ozone layer, and is a waste of applied nitrogen fertiliser. Nitrous oxide emissions from four commercial farms growing processing tomatoes {Solatium lycopersicum) in the Rochester-Echuca-Boort area of Victoria, Australia, were monitored during the 2014-15 growing season. Low crop nitrous oxide emissions were measured, ranging from 0.23 to 1.51 kg N2O-N ha 1across the four farms. The emissions intensity of the four farms was very low, ranging from 0.0014 to 0.011 kg N20-N t1 fruit. The greatest risk period for nitrous oxide emissions was during plant establishment, due to the reliance on subsurface drip andthe need to apply excess water to wet the soil surface. Inadvertently, the application of metham sodium appears to be responsible for reducing average nitrous oxide emissions over the high-risk plant establishment period. In 2015, emissions after planting were 4.5 times greater when no metham sodium was applied. The low measured nitrous oxide emissions meant that the Cool Farm Tool, the main industry reporting tool, produced nitrous oxide emission estimates that were up to 11 times higher than those measured during the 2014-15 season. When compared with other produce, the Australian processing tomato sector is well placed, with very low emissions intensities.