02866nas a2200145   4500008004100000245012900041210006900170520232200239100001602561700002402577700002402601700001502625700001502640856006502655       2021                        eng d00aMechanisms influencing physically sequestered soil carbon in temperate restored grasslands in South Africa and North America0 aMechanisms influencing physically sequestered soil carbon in tem3 a<p>Sequestering carbon (C) into stable soil pools has potential to mitigate increasing atmospheric carbon dioxide concentrations. Carbon accrues in grassland soil restored from cultivation, but the amount of physically protected C (here measured as microaggregate-within-macroaggregate C) and predominant mechanisms of accrual are not well understood. We modeled the rate of physically protected carbon accrued in three mesic temperate perennial restored grasslands from cross-continental regions using datasets with a wide range of restoration ages from northeast Kansas, USA; southeast Nebraska, USA; and northeast Free State, South Africa. Further, we investigated major controls on the amount of physically protected C in each site using structural equation modeling. Variables in the structural equation model were root biomass, root C:N ratio, soil structure (indicated by bulk density, percent of macroaggregates on a per whole soil mass basis, and percent of microaggregate-within-macroaggregates on a per macroaggregate mass basis), microbial composition (indicated by microbial biomass C, total phospholipid fatty acid [PLFA] biomass, and PLFA biomass of arbuscular mycorrhizae fungi [AMF] biomass), and microaggregate-within-macroaggregate C on a per whole soil mass basis. Across all sites, physically protected C accrued at a rate of 16&thinsp;&plusmn;&thinsp;5 g m&minus;2 year&minus;1. Data from South Africa fit an a priori metamodel developed for northeast KS that hypothesized physically protected C could be explained as a function of microbial composition, soil structure, root C:N ratio, and root biomass (listed in order of strength of direct effect on physically protected C). In contrast to the model-based hypothesis, root C:N ratio was the strongest influence (negative) on physically protected C in South Africa. The lesser effect of AMF on physically protected C in South Africa was consistent with lower AMF biomass in arid environments. The hypothesized model did not fit southeast Nebraska data possibly due to high (~&thinsp;30%) clay content. Overall, these results suggest that physically protected C in soil with moderate amounts of clay (more than 10% and less than 30%) can be predicted with knowledge of roots (biomass and C:N ratio), microbial biomass, and soil aggregation.</p>1 aScott, D.A.1 aBach, Elizabeth, M.1 aPreez, Chris, C. Du1 aSix, Johan1 aBaer, S.G.  uhttps://link.springer.com/article/10.1007/s10533-021-00774-y02101nas a2200265   4500008004100000245010300041210006900144300001400213490000700227520132500234653001501559653001701574653001101591653002301602653001301625653002801638653001201666653000901678653000901687100002001696700001501716700001501731700001501746856007401761       2017                        eng d00aRestoration and management for plant diversity enhances the rate of belowground ecosystem recovery0 aRestoration and management for plant diversity enhances the rate  a355 - 3620 v273 a<p>The positive relationship between plant diversity and ecosystem functioning has been criticized for its applicability at large scales and in less controlled environments that are relevant to land management. To inform this gap between ecological theory and application, we compared recovery rates of belowground properties using two chronosequences consisting of continuously cultivated and independently restored fields with contrasting diversity management strategies: grasslands restored with high plant richness and managed for diversity with frequent burning (n = 20) and grasslands restored with fewer species that were infrequently burned (n = 15). Restoration and management for plant diversity resulted in 250% higher plant richness. Greater recovery of roots and more predictable recovery of the active microbial biomass across the high diversity management strategy chronosequence corresponded with faster recovery of soil structure. The high diversity grasslands also had greater nutrient conservation indicated by lower available inorganic nitrogen. Thus, mesic grasslands restored with more species and managed for high plant diversity with frequent burning enhances the rate of belowground ecosystem recovery from long-term disturbance at a scale relevant to conservation practices on the landscape</p>10aAggregates10aBiodiversity10acarbon10aEcosystem function10anitrogen10aphospholipid fatty acid10aprairie10aroot10asoil1 aKlopf, Ryan, P.1 aBaer, S.G.1 aBach, E.M.1 aSix, Johan  uhttps://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/eap.1503