Cover crops support the climate change mitigation potential of agroecosystems

carbon stock increases depending on the type of cover crop. For example, a soil organic carbon increase of 0.26 Mg CO2e ha-1 a-1 has been found for a winter vetch cover crop [13]. A much larger increase in soil carbon of 5.12 Mg CO2e ha-1 a-1 was found by Abdalla et al. [25] for non-legume cover crops. The weighted mean of all studies investigated shows an average sequestration of 1.43 Mg CO2e ha-1 a-1 (95% CI, 0.86, 2.01). Based on the included studies, grass cover crops lead to a 2.3-times higher soil organic carbon sequestration than legume cover crops. Cover crop mixtures of grasses, legumes, and various other species are in the mid- dle of the field in sequestration performance [26]. Fig 2 shows the included carbon sequestration results, confidence intervals and the pooled effect. If more than one result is shown from one study in Fig 2 this literature showed results from multiple experiments. 3.3. Nitrogen fixation Legume cover crops are able to fix atmospheric nitrogen and transfer it to the rhizosphere or utilize it for their own biomass. The decay of nitrogen-rich legume litter or rhizosphere prod- ucts contribute to soil nitrogen fertilization and plant nutrition of the crop following the cover crop [13]. The amount of nitrogen fixed depends on the legume species and/or the companion Fig 2. Forest plot of included literature on carbon sequestration effects. https://doi.org/10.1371/journal.pone.0302139.g002 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 9 / 20