Plant diversity can alter soil carbon stocks, but the effects are difficult to predict due to the multitude of mechanisms involved. We propose that these mechanisms and their outcomes can be better understood by testing how plant diversity affects particulate organic matter (POM) and mineral-associated organic matter (MAOM) depending on whether MAOM storage is "saturated" and the total soil organic matter pool is limited by plant inputs. Such context-dependency of plant-diversity effects on POM, MAOM, and total soil organic matter helps explain inconsistencies in plant-diversity-soil-carbon relationships across studies. Further illumination of this context-dependency is required to better predict consequences of biodiversity losses and gains, and manage ecosystems as carbon sinks and nutrient stores.

• MeSH
• biodiverzita * MeSH
• ekosystém MeSH
• minerály * analýza   chemie   MeSH
• organické látky * analýza   MeSH
• pevné částice * analýza   MeSH
• půda * chemie   MeSH
• rostliny * metabolismus   klasifikace   MeSH
• sekvestrace uhlíku MeSH
• uhlík analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• minerály * MeSH
• organické látky * MeSH
• pevné částice * MeSH
• půda * MeSH
• uhlík MeSH

Fauna is highly abundant and diverse in soils worldwide, but surprisingly little is known about how it affects soil organic matter stabilization. Here, we review how the ecological strategies of a multitude of soil faunal taxa can affect the formation and persistence of labile (particulate organic matter, POM) and stabilized soil organic matter (mineral-associated organic matter, MAOM). We propose three major mechanisms - transformation, translocation, and grazing on microorganisms - by which soil fauna alters factors deemed essential in the formation of POM and MAOM, including the quantity and decomposability of organic matter, soil mineralogy, and the abundance, location, and composition of the microbial community. Determining the relevance of these mechanisms to POM and MAOM formation in cross-disciplinary studies that cover individual taxa and more complex faunal communities, and employ physical fractionation, isotopic, and microbiological approaches is essential to advance concepts, models, and policies focused on soil organic matter and effectively manage soils as carbon sinks, nutrient stores, and providers of food.

• MeSH
• ekosystém MeSH
• mikrobiota MeSH
• minerály chemie   MeSH
• organické látky MeSH
• půda * chemie   MeSH
• půdní mikrobiologie * MeSH
• uhlík chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• minerály MeSH
• organické látky MeSH
• půda * MeSH
• uhlík MeSH

Much research focuses on increasing carbon storage in mineral-associated organic matter (MAOM), in which carbon may persist for centuries to millennia. However, MAOM-targeted management is insufficient because the formation pathways of persistent soil organic matter are diverse and vary with environmental conditions. Effective management must also consider particulate organic matter (POM). In many soils, there is potential for enlarging POM pools, POM can persist over long time scales, and POM can be a direct precursor of MAOM. We present a framework for context-dependent management strategies that recognizes soils as complex systems in which environmental conditions constrain POM and MAOM formation.

• MeSH
• minerály MeSH
• pevné částice MeSH
• půda * MeSH
• sekvestrace uhlíku * MeSH
• uhlík MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• minerály MeSH
• pevné částice MeSH
• půda * MeSH
• uhlík MeSH

Microbial necromass is a central component of soil organic matter (SOM), whose management may be essential in mitigating atmospheric CO2 concentrations and climate change. Current consensus regards the magnitude of microbial necromass production to be heavily dependent on the carbon use efficiency of microorganisms, which is strongly influenced by the quality of the organic matter inputs these organisms feed on. However, recent concepts neglect agents relevant in many soils: earthworms. We argue that the activity of earthworms accelerates the formation of microbial necromass stabilized in aggregates and organo-mineral associations and reduces the relevance of the quality of pre-existing organic matter in this process. Earthworms achieve this through the creation of transient hotspots (casts) characterized by elevated contents of bioavailable substrate and the efficient build-up and quick turnover of microbial biomass, thus converting SOM not mineralized in this process into a state more resistant against external disturbances, such as climate change. Promoting the abundance of earthworms may, therefore, be considered a central component of management strategies that aim to accelerate the formation of stabilized microbial necromass in wide locations of the soil commonly not considered hotspots of microbial SOM formation.

• Klíčová slova
• aggregates, carbon sequestration, casts, concept, hotspot, organo-mineral associations, substrate quality,
• MeSH
• biomasa MeSH
• Oligochaeta * MeSH
• půda * chemie   MeSH
• půdní mikrobiologie MeSH
• uhlík chemie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• půda * MeSH
• uhlík MeSH

Soil is the largest terrestrial reservoir of organic carbon and is central for climate change mitigation and carbon-climate feedbacks. Chemical and physical associations of soil carbon with minerals play a critical role in carbon storage, but the amount and global capacity for storage in this form remain unquantified. Here, we produce spatially-resolved global estimates of mineral-associated organic carbon stocks and carbon-storage capacity by analyzing 1144 globally-distributed soil profiles. We show that current stocks total 899 Pg C to a depth of 1 m in non-permafrost mineral soils. Although this constitutes 66% and 70% of soil carbon in surface and deeper layers, respectively, it is only 42% and 21% of the mineralogical capacity. Regions under agricultural management and deeper soil layers show the largest undersaturation of mineral-associated carbon. Critically, the degree of undersaturation indicates sequestration efficiency over years to decades. We show that, across 103 carbon-accrual measurements spanning management interventions globally, soils furthest from their mineralogical capacity are more effective at accruing carbon; sequestration rates average 3-times higher in soils at one tenth of their capacity compared to soils at one half of their capacity. Our findings provide insights into the world's soils, their capacity to store carbon, and priority regions and actions for soil carbon management.

• MeSH
• minerály MeSH
• půda * MeSH
• sekvestrace uhlíku MeSH
• uhlík * MeSH
• zemědělství MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• minerály MeSH
• půda * MeSH
• uhlík * MeSH