Universality of priming effect: an analysis using thirty five soils with contrasted properties sampled from five continents

Authors: PERVEEN, NAZIA - Inland Northwest Research Alliance, Inra; BAROT, SEBASTIEN - Institute For Research And Development (IRD); MAIRE, VINCENT - University Of Quebec; COTRUFO, FRANCESCA - Colorado State University; SHAHZAD, TANVIR - University Of Faisalabad; BLAGODATSKAYA, EVGENIA - Russian Academy Of Sciences; Stewart, Catherine; DING, WEIXIN - Chinese Academy Of Sciences; SIDDIQ, MUHAMMAD - Frankfurt University; DIMASSI, BASSEM - Inland Northwest Research Alliance, Inra; MARY, BRUNO - Inland Northwest Research Alliance, Inra; FONTAINE, SEBASTIEN - Inland Northwest Research Alliance, Inra

Submitted to: Soil Biology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2019
Publication Date: 4/2/2019
Citation: Perveen, N., Barot, S., Maire, V., Cotrufo, F., Shahzad, T., Blagodatskaya, E., Stewart, C.E., Ding, W., Siddiq, M., Dimassi, B., Mary, B., Fontaine, S. 2019. Universality of priming effect: an analysis using thirty five soils with contrasted properties sampled from five continents. Soil biology and biochemistry. 134:162-171. https://doi.org/10.1016/j.soilbio.2019.03.027.
DOI: https://doi.org/10.1016/j.soilbio.2019.03.027

Interpretive Summary: Decomposition (mineralization) of soil organic matter (SOM) is the first source of available nutrients for plant uptake in agroecosystems. This decomposition of SOM results in global carbon (C) emissions that are 7 times greater than other anthropogenic emissions of CO2. Therefore, improved understanding of drivers of SOM mineralization, could help agricultural researchers/workers design sustainable practices that reduce fertilizer use and conserve SOM. Those soil sustaining practices can then mitigate global warming by sequestering atmospheric C into soil C. How inherent soil properties affect SOM distribution among physical fractions and how inherent soil properties affect decomposition is still unclear. We addressed these knowledge gaps by incubating thirty-five soils with or without addition of 13C labeled cellulose for 262 days. The soils were sampled from different land uses and depths of contrasting soil types from five continents (Asia, Europe, America, Australia and Africa). Variations in how 13C labeled cellulose addition affected mineralization of SOM (known as the priming effect (PE)) were mainly explained by soil characteristics and not by land use. We found that the PE increased with the relative abundance of SOM not bound or associated with soil minerals and also increased in those soils rich in nitrogen (N). This research helps us to understand the interactions of native SOM and C rich additions and how those additions affect the final amount of decomposition and C emissions from soil. The data collected in these experiments were useful in helping us understand the dynamics of C and N cycling in soils and how that cycling affects soil CO2 emissions into the atmosphere.

Technical Abstract: A general occurrence of the phenomenon of priming effect (PE) across varying land use and soil types has not been established so far, particularly on a large geographical scale. Moreover, the impacts of soil properties and soil organic matter (SOM) distribution among physical fractions on the magnitude of PE are still unclear. We addressed these knowledge gaps by incubating thirty-five soils with or without addition of 13C labeled cellulose for 262 days. The soils were sampled from different land uses and depths of contrasting soil types from five continents (Asia, Europe, America, Australia and Africa). Results showed positive PE in all soils including grassland, cropland, forest, savannah and orchard. On average, the cumulative PE represented 27.0 ± 28.7 % of the CO2 efflux in control soils and 28.48 ± 21.08 % of the remaining/unrespired cellulose-C. The PE was 72.1 % higher in surface than deep soils suggesting that surface soils are more prone to PE induced by cellulose addition. Variations in PE were mainly explained by soil characteristics and not by land use. We found that the PE increased with the relative abundance of SOM not associated with minerals and rich in nitrogen (N). The observation of systematic positive PE in all soils suggested that microbial co-metabolism to decompose SOM is a widespread microbial strategy. Our results also support the idea that microorganisms use co-metabolism to mine nutrients in SOM since they target N-rich fractions. However, other mechanisms are also at play since positive PE was maintained despite the high availability of mineral nutrients. Overall, PE is a worldwide process playing a major role for soil C dynamics, especially in N-rich soils.