Soil biology, soil health, and soil carbon

Soil biology, soil health, and soil carbon

While interest in a more active Northern agriculture grows, the information on Northern agricultural regions suffers from the overall lack of locally relevant data and from a lack of coherent verification of the quality of extant data. This is critical as northern agriculture might take place in microclimatic niches within the region, with unique soil and infrastructural conditions. This gap can only be filled with locally relevant, but a nationally consistent, approach to data collection, verification and implementation. A first step towards a northern solution to Northern crop adaptation through locally relevant plant-soil functions systems is an understanding of the locally relevant soil food webs and phytobiomes. This involves an understanding of soil biota and its functioning and the microbiology along the soil-to-plant continuum. Functions are thus governed by the interrelationship between soil and plants as a continuum of habitats for microbiota and microfauna. To modify functions within this soil-to-plant domain by taxonomic and functional modification of the biological communities, either by introducing preferred (micro)organisms or by their in-situ management directed selection (i.e., through modification in the relevant abiotic conditions), one must understand the governing drivers. Local-resource based management of soils must be verified  and tuned to ensure best functioning of soil biota and microbiota.

Thus, it is argued that stable, functional soil food webs, facilitated by adaptive crops and cropping practices can naturally enhance C sequestration mitigate agriculture’s C footprint, and lower GHG emissions.

Currently, there is no standard indicator or set of indicators of soil quality or sustainability though several countries have developed soil quality assessment approaches. For example, the USA, Canada, and the Netherlands all use national frameworks to assess soil quality yet each of these programs assess different sets of indicators at different spatial scales with different types of land use and managements. SOM, acidity, available phosphorus, water storage, bulk density, available potassium, texture, total N, electrical conductivity, and cation exchange capacity are the top ten most frequently used indicators in soil quality assessments. In addition to these traditional abiotic indicators, biological indicators can be used to quantify sustainability in the face of LULUC and to understand soil quality.

An optimal indicator of soil quality is practical to sample and measure, reliable and cost-efficient, sensitive to changes in soil conditions and management and has a clear interpretation scheme. Biological indicators of soil quality must be meaningful, standardized, measurable and cost-efficient, policy-relevant, validated across spatial and temporal scales, be easily understood, and accurate in describing the changes they monitor. Biological indicators such as microbes and free-living nematodes have a root in the organic farming movement and are, for example, often used across Europe to assess soil quality.

Examples of most often considered biological indicators are:

Soil microbial biomass

Microbial communities (from metagenomics to metabolomics and metatranscriptomics) as indicators of soil functional status

Soil respiration (i.e., the cumulative CO2 released from below ground plant material by biota, thus an indicator of system decomposition and mineralization while also taking root respiration into consideration

Protozoa

Earthworms (of variable utility given their natural non-uniform distribution and presence across latitudes!) rthworms, along.

(Micro)arthropods (as contributors to nutrient fluxes through the decomposition of OM, regulating microbiomes).

Free-living nematodes (essential to the fluxes of C, nutrients, and energy in soil systems; occupy a range of nodes in the soil food web: bacterivores, fungivores, herbivores, omnivores, and predators and a food source for other fauna. Their measurements might be descriptive of the entire food web functions)

Projects

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BioSoil North

In search of food security in the boreal regions of Canada land use conversion (LUC) is used to expand agriculture into boreal forests or natural lands. LUC is strongly supported…

project

Carbon in Global Boreal and Alpine Soils Under Climate Change-Driven Land Use

Hugh C. Morris Experiential Fellowship (Kimberley Foundation) The Hugh C. Morris Experiential Fellowship sends a student away from the complacency of their home institution (classroom and laboratory) to study at…

project

Initial assessment of a new research farm: Pye Farm, Labrador

Labrador (the mainland portion of the province of Newfoundland and Labrador) is a sparsely populated but actively growing region of Canada. Like Yukon and northern Ontario, Labrador offers a snapshot…

project

Composting, vermicomposting

coming soon

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Canadian Soil Biodiversity Observatory - Atlantic Provinces

AAFC has funded two projects to characterize soil biodiversity and its relationships with soil physico-chemical parameters and land use. The Atlantic provinces project is led by Dr. Louis-Pierre Comeau and…

Articles

article

Soil carbon in the boreal region under climate and land use change

Vallotton, JD, Unc A. 2024. Soil Use and Management, 40, e13108. https://doi.org/10.1111/sum.13108 Abstract Carbon cycling in boreal regions is controlled naturally by fire disturbance, climate, hydrology, snowmelt, soil heterogeneity, acidity, low nitrogen and phosphorus availability, mycorrhizal distribution, plant cover, and cryoturbation/permafrost at the…

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Corrigendum to “A review of nematodes as biological indicators of sustainable functioning for northern soils undergoing land-use conversion” [Appl. Soil Ecol. 195 (2023) 104762]

Young EH, Unc A. 2024. Applied Soil Ecology, Pages 105208, Volume 195, March 2024, 105208 https://doi.org/10.1016/j.apsoil.2023.105208

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A review of nematodes as biological indicators of sustainable functioning for northern soils undergoing land-use conversion. 

Young EH, Unc A. 2023. Applied Soil Ecology, 183: 104762, https://doi.org/10.1016/j.apsoil.2022.104762 Highlights Abstract Food webs and the functional status of soils are governed primarily by microbial carbon and nitrogen fluxes as determined by ecosystem type and management. In boreal regions, expanding and intensifying agriculture affects the…

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Soil respiration

J. D. Vallotton, S. Blagodatsky and A. Unc, In: Encyclopedia of Soils in the Environment (Second Edition), edited by M. J. Goss and M. Oliver, Volume 1, 2023, Pages 369-378, Academic Press 2023  https://doi.org/10.1016/B978-0-12-822974-3.00264-0 Soil respiration is a useful indicator of…

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Impact of fertilizer source on the dynamics of carbon and nutrients in a podzol designated for land-use conversion. 

Tingskou, R., &  Unc, A. (2023).  Soil Use and Management,  39,  1491–1503. https://doi.org/10.1111/sum.12906 Boreal lands have long been considered unsuitable for agriculture. Climate change projections support a shift towards increased agricultural production in boreal ecosystems via land use conversion. Depending on the conversion protocol, the new…

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Soil nematode trophic structure and biochar addition in recently converted boreal lands

E. H. Young, J. Abedin and A. Unc, Soil Research 2023 Vol. 61 Issue 5 Pages 456-467 https://doi.org/10.1071/SR22228 Context: Climate change facilitated expansion of agriculture into northern regions increases the amount of Podzol dominated farmland. Biochar can improve poor growing…

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Utility of wood ash, paper sludge and biochar for the mitigation of greenhouse gases emissions from acid boreal soils

A. O. Medaiyese, J. Wu and A. Unc, Journal of Environmental Management 2023 Vol. 330 Pages 117202 https://doi.org/10.1016/j.jenvman.2022.117202 Land-use change in the boreal forest region leads to agriculture to be carried out on acid, shallow and low fertility soils. To…

article

A review of nematodes as biological indicators of sustainable functioning for northern soils undergoing land-use conversion

E. H. Young and A. Unc, Applied Soil Ecology 2023 Vol. 183 Pages 104762, https://doi.org/10.1016/j.apsoil.2022.104762 Food webs and the functional status of soils are governed primarily by microbial carbon and nitrogen fluxes as determined by ecosystem type and management. In…

article

Ex situ soil respiration assessment using minimally disturbed microcosms and dried–sieved soils; comparison of methods to assess soil health

L.-P. Comeau, K. MacKinley, A. Unc and J. Vallotton, Canadian Journal of Soil Science 2022 Vol. 103 Issue 1 Pages 143-151, https://doi.org/10.1139/cjss-2021-0143 Soil respiration measurements are commonly used as soil health indicators. Several ex situ soil respiration methods exist, but…

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The impacts of rock pulverization on soil quality and functional soil nematode and respiration properties of boreal lands converted from forest to agricultural use

E. H. Young, J. D. Vallotton, A. J. Kedir, A. O. Medaiyese, C. Goyer, L.-P. Comeau and A. Unc, Canadian Journal of Soil Science 2022 Vol. 102 Issue 4 Pages 977-990, https://doi.org/10.1139/cjss-2022-0007 Rock pulverization is recommended when converting boreal forests…

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The effect of human trampling activity on a soil microbial community at the Oulanka Natural Reserve, Finland

C. Sherman, A. Unc, T. Doniger, R. Ehrlich and Y. Steinberger, Applied Soil Ecology 2019 Vol. 135 Pages 104-112, https://doi.org/10.1016/j.apsoil.2018.11.013 Functional and taxonomic diversities of microbial communities in Arctic soils are governed by the extreme abiotic environment and affected by…