Cover crops support the climate change mitigation potential of agroecosystems

Therefore, we conclude that positive aspects of cover cropping always superimpose the nega- tive impacts. All scenarios show a positive NCCMI. 4.2. Comparing overall results to existing literature In contrast to Kaye and Quemada [22], this study is first to include land use effects based on the yield gain caused by cover crops. Furthermore, our study uses a systematic literature review and quantifies the climate change mitigation impact for all of EU-27, which demonstrates the magnitude of climate change mitigation opportunities of cover crops. So far no other literature has extrapolated the climate change mitigation impact of cover crops to a country or region. Overall, Kaye and Quemada [22] found a climate change mitigation effect of 1.16–1.35 Mg CO2e ha-1 a-1 from cover crops, which is lower than that calculated in this study. This discrep- ancy is a result of different analyzed literature and the inclusion of land use effects in our research. In addition, Abdalla et al. [25] showed a slightly lower climate change mitigation impact from cover crops compared to our results of 2.06 Mg CO2e ha−1 a−1(95% CI -0.04, 4.16). The study, however, does not consider land use change effects (1.51 Mg CO2e ha-1 a-1 in our study), albedo change, emissions for cover crop seed production, and additional machin- ery operations. If the study would have considered these factors, their results would be more comparable to those in our study. 4.3. Limitations A limitation of this study is that we did not include erosion reduction of cover crops as a cli-

mate benefit due to the high data variability and uncertainty of its climate impact. Further- more, the use of carbon opportunity cost as suggested by Searchinger at al. [11] is criticized by Fig 3. Sankey plots describing gains and losses of different scenarios for the NCCMI. Numbers are given as Mg CO2e ha-1. https://doi.org/10.1371/journal.pone.0302139.g003 PLOS ONE Cover crops support the climate change mitigation potential of agroecosystems PLOS ONE | https://doi.org/10.1371/journal.pone.0302139 May 8, 2024 15 / 20