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

2018–2020 than for 2017–2019 (-169%). Cumulative energy demand was 17% higher for 2018–2020 than for 2017–2019 for both the conservation and conventional systems. 3.4 Change in soil organic C stock over time of scenarios According to the SIMEOS-AMG simulation tool, initial SOC stock was 38.4 t/ha for the three scenarios (Fig 3). Over time, SOC stock decreased in the Conv scenario but increased in the Cons_CC and Cons_full scenarios. After 100 years, SOC had not completely reached Fig 2. Contribution of direct emissions, seed, compost, mineral fertilisers, pesticides, irrigation, other field operations, and transport of inputs to the climate change impact for individual crops. Values are means for 2017–2018 and 2018–2019 for wheat, for 2019 and 2020 for popcorn, and for 2018–2019 and 2019–2020 for cover crops. https://doi.org/10.1371/journal.pone.0285586.g002 Table 5. Impacts of conventional and conservation crop rotations (2017–2019 and 2019–2020) for the land management (ha.year) functional unit. Difference expresses impacts of the conservation rotation relative to those of the conventional rotation. Values in brackets for Difference correspond to the effects of a 10% increase or decrease of the conventional crop yields. Impact category Unit Crop rotation Conventional Conservation 2017–2019 2018–2020 Mean 2017–2019 2018–2020 Mean Difference (%) Climate change kg CO2 eq 3720 4014 3867 1211 -344 434 -89 (-97/-82) Terrestrial acidification kg SO2 eq 48.5 47.9 48.2 51.9 53.3 52.6 +9 Marine eutrophication kg N eq 8.38 8.43 8.41 7.75 7.85 7.80 -7

Land competition m2a 10 293 10 436 10 365 10 531 10 774 10 653 +3 Cumulative energy demand MJ 21 549 24 626 23 087 21 777 25 513 23 645 +2 https://doi.org/10.1371/journal.pone.0285586.t005 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 10 / 18