The Ecology of Soil Carbon: Pools, Vulnerabilities, and Biotic and Abiotic Controls

Annual Review of Ecology Evolution and Systematics, Год журнала: 2017, Номер 48(1), С. 419 - 445

Опубликована: Сен. 6, 2017

Soil organic matter (SOM) anchors global terrestrial productivity and food fiber supply. SOM retains water soil nutrients stores more carbon than do plants the atmosphere combined. is also decomposed by microbes, returning CO 2 , a greenhouse gas, to atmosphere. Unfortunately, stocks have been widely lost or degraded through land use changes unsustainable forest agricultural practices. To understand its structure function maintain restore SOM, we need better appreciation of (SOC) saturation capacity retention above- belowground inputs in SOM. Our analysis suggests root are approximately five times likely an equivalent mass aboveground litter be stabilized as Microbes, particularly fungi bacteria, faunal webs strongly influence decomposition at shallower depths, whereas mineral associations drive stabilization depths greater ∼30 cm. Global uncertainties amounts locations include extent wetland, peatland, permafrost systems factors that constrain such shallow bedrock. In consideration these uncertainties, estimate SOC 3 m between 2,270 2,770 Pg, respectively, but could much 700 Pg smaller. Sedimentary deposits deeper contain >500 additional SOC. Soils hold largest biogeochemically active pool on Earth critical for stabilizing atmospheric concentrations. Nonetheless, pressures soils continue from management, including increasing bioenergy production.

Язык: Английский

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Particulate organic matter as a functional soil component for persistent soil organic carbon

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Июль 5, 2021

Abstract The largest terrestrial organic carbon pool, in soils, is regulated by an intricate connection between plant inputs, microbial activity, and the soil matrix. This manifested how microorganisms, key players transforming plant-derived into carbon, are controlled physical arrangement of inorganic particles. Here we conduct incubation isotopically labelled litter to study effects structure on fate litter-derived matter. While activity fungal growth enhanced coarser-textured soil, show that occlusion matter aggregates formation organo-mineral associations occur concurrently fresh surfaces regardless structure. These two mechanisms—the most prominent processes contributing persistence matter—occur directly at plant–soil interfaces, where constitute a nucleus build-up persistence. We extend notion litter, i.e., particulate matter, from solely easily available labile substrate, functional component which determined.

Язык: Английский

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Anaerobic microsites have an unaccounted role in soil carbon stabilization

Nature Communications, Год журнала: 2017, Номер 8(1)

Опубликована: Ноя. 20, 2017

Soils represent the largest carbon reservoir within terrestrial ecosystems. The mechanisms controlling amount of stored and its feedback to climate system, however, remain poorly resolved. Global models assume that cycling in upland soils is entirely driven by aerobic respiration; impact anaerobic microsites prevalent even well-drained missed this conception. Here, we show are important regulators soil persistence, shifting microbial metabolism less efficient respiration, selectively protecting otherwise bioavailable, reduced organic compounds such as lipids waxes from decomposition. Further, conditions leads a 10-fold increase volume-specific mineralization rate, illustrating sensitivity anaerobically protected disturbance. vulnerability future or land use change thus constitutes yet unrecognized carbon-climate should be incorporated into ecosystem models.

Язык: Английский

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Soil organic matter formation, persistence, and functioning: A synthesis of current understanding to inform its conservation and regeneration

Advances in agronomy, Год журнала: 2022, Номер unknown, С. 1 - 66

Опубликована: Янв. 1, 2022

Язык: Английский

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Thermodynamically controlled preservation of organic carbon in floodplains

Nature Geoscience, Год журнала: 2017, Номер 10(6), С. 415 - 419

Опубликована: Май 1, 2017

Язык: Английский

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Microbial spatial footprint as a driver of soil carbon stabilization

Nature Communications, Год журнала: 2019, Номер 10(1)

Опубликована: Июль 16, 2019

Abstract Increasing the potential of soil to store carbon (C) is an acknowledged and emphasized strategy for capturing atmospheric CO 2 . Well-recognized approaches C accretion include reducing disturbance, increasing plant biomass inputs, enhancing diversity. Yet experimental evidence often fails support anticipated gains, suggesting that our integrated understanding remains insufficient. Here we use a unique combination X-ray micro-tomography micro-scale enzyme mapping demonstrate first time plant-stimulated pore formation appears be major, hitherto unrecognized, determinant whether new inputs are stored or lost atmosphere. Unlike monocultures, diverse communities favor development 30–150 µm pores. Such pores micro-environments associated with higher activities, greater abundance such translates into spatial footprint microorganisms make on consequently storage capacity.

Язык: Английский

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A Global Meta‐Analysis of Grazing Impacts on Soil Health Indicators

Journal of Environmental Quality, Год журнала: 2018, Номер 47(4), С. 758 - 765

Опубликована: Апрель 5, 2018

Grazing lands support the livelihoods of millions people across nearly one-half globe. Soils are backbone stability and resilience in these systems. To determine livestock grazing impacts on soil health, we conducted a global meta-analysis organic carbon (SOC), total N, C/N ratio, bulk density responses to strategies (continuous, rotational, no grazing) intensities (heavy, moderate, light from 64 studies around world. Across all intensities, continuous significantly reduced SOC, C/N, N compared with grazing. Soil compaction (i.e., increased density) was greater under both rotational grazing; however, had lower than Rotational SOC not different The positive could create climate change mitigation opportunities. strategy comparisons were minimally conditioned by aridity class arid, subhumid, humid); complete observations notably limited or missing for many comparisons. For comparisons, found that management can influence function health outcomes; site-specific environmental factors play important moderating roles. Greater coordination regional, national, efforts, as well consistent guidelines evaluation, would help overcome knowledge gaps vastly improve our collective understanding providing policy impacts.

Язык: Английский

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Elevated moisture stimulates carbon loss from mineral soils by releasing protected organic matter

Nature Communications, Год журнала: 2017, Номер 8(1)

Опубликована: Ноя. 20, 2017

Abstract Moisture response functions for soil microbial carbon (C) mineralization remain a critical uncertainty predicting ecosystem-climate feedbacks. Theory and models posit that C declines under elevated moisture associated anaerobic conditions, leading to accumulation. Yet, iron (Fe) reduction potentially releases protected C, providing an under-appreciated mechanism destabilization moisture. Here we incubate Mollisols from ecosystems 3 /C 4 plant rotations at levels above field capacity over 5 months. Increased anaerobiosis initially suppress mineralization, consistent with theory. However, after 25 days, stimulates cumulative gaseous C-loss as CO 2 CH >150% of the control. Stable isotopes show older -derived released following Fe dominates losses. Counter theory, may significantly accelerate losses mineral soils weeks months—a mechanistic deficiency current Earth system models.

Язык: Английский

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Contrasting pathways of carbon sequestration in paddy and upland soils

Global Change Biology, Год журнала: 2021, Номер 27(11), С. 2478 - 2490

Опубликована: Март 13, 2021

Paddy soils make up the largest anthropogenic wetlands on earth, and are characterized by a prominent potential for organic carbon (C) sequestration. By quantifying plant- microbial-derived C in across four climate zones, we identified that accrual is achieved via contrasting pathways paddy upland soils. Paddies 39%-127% more efficient soil (SOC) sequestration than their adjacent counterparts, with greater differences warmer cooler climates. Upland replenished C, whereas enriched proportion of plant-derived because retarded microbial decomposition under anaerobic conditions induced flooding paddies. Under both land-use types, maximal contribution plant residues to SOC at intermediate mean annual temperature (15-20°C), neutral (pH~7.3), low clay/sand ratio. contrast, high (~24°C), pH (~5), large ratio favorable strengthening necromass. The necromass waterlogged paddies climates likely due fast anabolism from bacteria, fungi unlikely be involved as they aerobic. In scenario conversion upland, total 504 Tg may lost CO

Язык: Английский

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Crop rotations for increased soil carbon: perenniality as a guiding principle

Ecological Applications, Год журнала: 2017, Номер 28(1), С. 249 - 261

Опубликована: Ноя. 7, 2017

More diverse crop rotations have been promoted for their potential to remediate the range of ecosystem services compromised by biologically simplified grain-based agroecosystems, including increasing soil organic carbon (SOC). We hypothesized that functional diversity offers a more predictive means characterizing impact on SOC concentrations than species per se. Furthermore, we can either increase or decrease depending its associated (C) input soil. compiled database 27 cropping system sites and 169 systems, recorded rotations, (g C kg/soil), nitrogen (N) fertilizer applications (kg N·ha-1 ·yr-1 ), estimated (Mg C·ha-1 ). categorized into three broad categories: grain-only grain with cover crops, perennial crops. divided two sub-categories: cereal-only those included both cereals legume grain. compared changes in using mean effect sizes 95% bootstrapped confidence intervals. Cover cropped relative increased 42% 23% 6.3% 12.5%, respectively. Within cereal + decreased total (-16%), root (-12%), (-5.3%) rotations. found no within N rates mediated rotations: at low (≤75 kg was less high rates. Our results show is likely if it accompanied an input. Functionally concentrations, potentially exploiting niches time would otherwise be unproductive, is, "perenniality"

Язык: Английский

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