Conservation agriculture reduces climate change impact of a popcorn and wheat crop rotation

conservation and conventional wheat because they used identical amounts. The processes that contributed most were direct emissions (75% conventional and 76% conservation), mineral fertiliser (15% for both conventional and conservation), and other field operations (6% con- ventional and 4% conservation). For the cover crops, the processes that contributed most were direct emissions (84%), other field operations (13%), and seeds (3%). 3.3 Multi-impact comparison of crop rotations Impacts of the conventional and conservation rotations differed (Table 5). The conservation rotation had lower impacts than the conventional rotation for climate change (-89%) and marine eutrophication (-7%). A 10% decrease or increase of assumed yields of the crops in the conventional rotation resulted in a moderate (-97%/-82%) variation of the difference for the climate change impact (Table 5). The conservation rotation had somewhat higher impacts than the conventional rotation for terrestrial acidification (+9%), land competition (+3%), and cumulative energy demand (+2%). When comparing the 2017–2019 and 2018–2020 crop rotations, differences were small, except for climate change for the conservation rotation, which had much lower impacts for Fig 1. Contribution of soil organic carbon, direct emissions, seed, compost, mineral fertilisers, pesticides, field operations (including irrigation), and transport of inputs to the climate change impact for the two-year popcorn and wheat crop rotation in 2017–2019 and

2018–2020, for conventional and conservation rotations. Dots indicate net impact, which is equal to C sequestration minus greenhouse gas emissions. The inputs and direct emissions of the cover crops were attributed to the popcorn crops. https://doi.org/10.1371/journal.pone.0285586.g001 PLOS ONE Conservation agriculture reduces climate change impact of a crop rotation PLOS ONE | https://doi.org/10.1371/journal.pone.0285586 May 23, 2023 9 / 18