Anthropogenic activities leading to erosion-induced topsoil loss still present a pertinent threat to maize (Zea mays L.) productivity across the U.S. Corn Belt region. Using soil amendments has been proven effective in reversing the effects caused by erosion-induced topsoil loss and restoring agronomic productivity and yields to pre-eroded conditions. The current study investigated the impact of simulated erosion and repeated amendment application on agronomic productivity and yields over five growing seasons for a 23-year-old experiment at two central Ohio sites (Waterman Farm: WF; Western Station: WS). Simulated erosion/deposition was employed in 1997 to create three incremental topsoil depths (TSD) (20 cm topsoil removed (TSD-0); 0 cm topsoil removed (TSD-1); 20 cm topsoil added (TSD-2). Three soil amendments (inorganic, synthetic N fertilizer (INO); organic, compost manure (MAN); no amendment (CON)) were investigated for their ability to restore productivity in these cropping systems. Greater TSD produced higher germination counts and crop stand and yielded greater canopy cover during the initial five weeks after germination. The MAN amended soils observed higher values for the productivity parameters during the 2016–2020 growing seasons. Grain and biomass yields were 34–51% and 5–12% lower, respectively, for the TSD-0 level and 4–10% and 3–6% greater, respectively, for the TSD-2 level when compared to the undisturbed, TSD-1 level. Relative biomass yield losses (% per cm topsoil depth lost) were 0.921 for the WF site and 0.254 for the WS site, corresponding to average biomass losses (Mg ha−1 cm−1 yr−1) of 0.083 and 0.026 for each site. Relative grain yield losses (% per cm topsoil depth lost) were 1.29 for the WF site and 0.514 for the WS site, equating to mean grain losses (Mg ha−1 cm−1 yr−1) of 0.083 and 0.026 for each site. The rehabilitative capacity of the soil amendments followed a trend of INO > MAN at the WF site and MAN > INO > CON at the WS site. The deleterious effects of erosion on grain and biomass yields were found to be reversed with the addition of the INO and MAN amendments at the WS site due to improvements in soil health and SOC pools. The MAN amended soils produced grain and biomass yields that were nearly 2.5% and 5.6% greater than the INO amended soil when compared to the reference treatment (TSD-1-CON). This study demonstrates that sustainable soil management practices coupled with annual soil amendment addition can mitigate the deleterious effects of erosion and rebound maize yields to pre-eroded conditions for soils experiencing severe topsoil loss.

Accurate quantification of different soil organic carbon (SOC) fractions is needed to understand their relative importance in the global C cycle. Among the chemical methods of SOC fractionation, oxidative degradation is considered more promising because of its ability to mimic the natural microbial oxidative processes in soil. This study focuses on detailed understanding of changes in structural chemistry and isotopic signatures of SOC upon different oxidative treatments for assessing the ability of these chemicals to selectively isolate a refractory fraction of SOC. Replicated sampling (to ~1 m depth) of pedons classified as Typic Fragiudalf was conducted under four land uses (woodlot, grassland, no-till and conventional-till continuous corn [Zea mays L.]) at Wooster, OH. Soil samples (<2 mm) were treated with three oxidizing agents (hydrogen peroxide (H2O2), disodium peroxodisulfate (Na2S2O8) and sodium hypochlorite (NaOCl)). Oxidation resistant residues and the bulk soil from A1/Ap1 horizons of each land use were further analyzed by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy and accelerator mass spectrometry to determine structural chemistry and 14C activity, respectively. Results indicated that, oxidation with NaOCl removed significantly less SOC compared to Na2S2O8 and H2O2. The NMR spectra revealed that NaOCl oxidation preferentially removed lignin-derived compounds at 56 ppm and at 110-160 ppm. On the other hand, the SOC resistant to Na2S2O8 and H2O2 oxidation were enriched with alkyl C groups, which dominate in recalcitrant macromolecules. This finding was corroborated by the 14C activity of residual material, which ranged from -542 to -259‰ for Na2S2O8 resistant SOC and -475 to -182‰ for H2O2 resistant SOC as compared to relatively greater 14C activity of NaOCl resistant residues (-47 to 61‰). Additionally, H2O2 treatment on soils after light fraction removal was more effective in isolating the oldest (14C activity of -725 to -469‰) SOC fraction. The Δ14C signature of SOC removed by different oxidizing agents, calculated by mass balance, was more or less similar irrespective of the difference in labile SOC removal efficiency. This suggests that SOC isolated by many fractionation methods is still a mixture of much younger and older material and therefore it is very important that the labile SOC should be completely removed before measuring the turnover time of stable and refractory pools of SOC. © 2009 Springer Science+Business Media B.V.

This special issue provides an assessment of the contribution of soils to Nature's Contributions to People (NCP). Here, we combine this assessment and previously published relationships between NCP and delivery on the UN Sustainable Development Goals (SDGs) to infer contributions of soils to the SDGs. We show that in addition to contributing positively to the delivery of all NCP, soils also have a role in underpinning all SDGs. While highlighting the great potential of soils to contribute to sustainable development, it is recognized that poorly managed, degraded or polluted soils may contribute negatively to both NCP and SDGs. The positive contribution, however, cannot be taken for granted, and soils must be managed carefully to keep them healthy and capable of playing this vital role. A priority for soil management must include: (i) for healthy soils in natural ecosystems, protect them from conversion and degradation; (ii) for managed soils, manage in a way to protect and enhance soil biodiversity, health and sustainability and to prevent degradation; and (iii) for degraded soils, restore to full soil health. We have enough knowledge now to move forward with the implementation of best management practices to maintain and improve soil health. This analysis shows that this is not just desirable, it is essential if we are to meet the SDG targets by 2030 and achieve sustainable development more broadly in the decades to come. This article is part of the theme issue 'The role of soils in delivering Nature's Contributions to People'.