Arbuscular mycorrhiza enhances rhizodeposition and reduces the rhizosphere priming effect on the decomposition of soil organic matter

2020 ◽  
Vol 140 ◽  
pp. 107641 ◽  
Author(s):  
Jie Zhou ◽  
Huadong Zang ◽  
Sebastian Loeppmann ◽  
Matthias Gube ◽  
Yakov Kuzyakov ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Arbuscular Mycorrhiza ◽  
Priming Effect ◽  
Rhizosphere Priming Effect

scholarly journals Glomalin – an interesting protein part of the soil organic matter

2020 ◽  
Vol 15 (No. 2) ◽  
pp. 67-74 ◽  
Author(s):  
Vítězslav Vlček ◽  
Miroslav Pohanka
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Arbuscular Mycorrhiza ◽  
Mycorrhizal Fungi ◽  
Biological Diversity ◽  
Agricultural Practices ◽  
Arbuscular Mycorrhizal ◽  
Fulvic Acids ◽  
Soil Parameters ◽  
Citrate Buffer

The negative effects of the current agricultural practices include erosion, acidification, loss of soil organic matter (dehumification), loss of soil structure, soil contamination by risky elements, reduction of biological diversity and land use for non-agricultural purposes. All these effects are a huge risk to the further development of soil quality from an agronomic point of view and its resilience to projected climate change. Organic matter has a crucial role in it. Relatively significant correlations with the quality or the health of soil parameters and the soil organic matter or some fraction of the soil organic matter have been found. In particular, Ctot, Cox, humic and fulvic acids, the C/N ratio, and glomalin. Our work was focused on glomalin, a glycoprotein produced by the hyphae and spores of arbuscular mycorrhizal fungi (AMF), which we classify as Glomeromycota. Arbuscular mycorrhiza, and its molecular pathways, is not a well understood phenomenon. It appears that many proteins are involved in the arbuscular mycorrhiza from which glomalin is probably one of the most significant. This protein is also responsible for the unique chemical and physical properties of soils and has an ecological and economical relevance in this sense and it is a real product of the mycorrhiza. Glomalin is very resistant to destruction (recalcitrant) and difficult to dissolve in water. Its extraction requires specific conditions: high temperature (121°C) and a citrate buffer with a neutral or alkaline pH. Due to these properties, glomalin (or its fractions) are very stable compounds that protect the soil aggregate surface. In this review, the actual literature has been researched and the importance of glomalin is discussed.  

scholarly journals Regulation of priming effect by soil organic matter stability over a broad geographic scale

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Leiyi Chen ◽  
Li Liu ◽  
Shuqi Qin ◽  
Guibiao Yang ◽  
Kai Fang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Priming Effect ◽  
Basal Respiration ◽  
Soil Conditions ◽  
The Tibetan Plateau ◽  
Geographic Scale ◽  
Soil C ◽  
Chemical Structures ◽  
C Dynamics

Abstract The modification of soil organic matter (SOM) decomposition by plant carbon (C) input (priming effect) represents a critical biogeochemical process that controls soil C dynamics. However, the patterns and drivers of the priming effect remain hidden, especially over broad geographic scales under various climate and soil conditions. By combining systematic field and laboratory analyses based on multiple analytical and statistical approaches, we explore the determinants of priming intensity along a 2200 km grassland transect on the Tibetan Plateau. Our results show that SOM stability characterized by chemical recalcitrance and physico-chemical protection explains more variance in the priming effect than plant, soil and microbial properties. High priming intensity (up to 137% of basal respiration) is associated with complex SOM chemical structures and low mineral-organic associations. The dependence of priming effect on SOM stabilization mechanisms should be considered in Earth System Models to accurately predict soil C dynamics under changing environments.

scholarly journals An Approach to Incorporate Rhizosphere Priming Effect into Soil Organic Matter Models

2021 ◽  
Author(s):  
Oleg Chertov ◽  
Yakov Kuzyakov ◽  
Irina Priputina ◽  
Pavel Frolov ◽  
Vladimir Shanin ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Priming Effect ◽  
C:N Ratio ◽  
Target Function ◽  
Terrestrial Ecosystems ◽  
Model Verification ◽  
Mineral N ◽  
Soil System ◽  
Plant Soil

Abstract Purpose. This study is aimed to develop a model of priming effect (accelerated mineralisation of soil organic matter (SOM)) induced by root exudate input into nitrogen (N) limited rhizosphere soil as a typical case for most terrestrial ecosystems. This ecologically important process in the functioning of the “plant-soil” system was parameterized for temperate and boreal forests.Methods. A model of priming effect has been developed based on the concept of N mining to making up for the N scarcity in exudates by accelerating SOM mineralisation. Lacking N for microbial growth is mined from the SOM mineralisation considering C:N ratio of soil. The model has a built-in food web module, which calculates soil fauna feeding on microorganisms, the release of by-products of faunal metabolism and mineral N used for root uptake.Results. The model verification demonstrated the similar order of the priming effect as in the published experiments. Testing at the pedon level revealed a high sensitivity of the model to N content in root exudates. Testing of the model at the ecosystem level revealed that CO2 emission from the priming can reach 25–30% of CO2 emission from the whole Ah horizon of forest soil. The same intensities were simulated for the fauna-derived N released within the rhizosphere.Conclusion. The new model reflects important ecological consequences of the main target function of priming effects within the “plant – soil – microorganisms – fauna” system – the microbial acceleration of C and N cycling in the rhizosphere and detritusphere to mobilise mineral N for plants.

scholarly journals Colimitation of decomposition by substrate and decomposers – a comparison of model formulations

2008 ◽  
Vol 5 (1) ◽  
pp. 163-190 ◽  
Author(s):  
T. Wutzler ◽  
M. Reichstein
Keyword(s):  
Organic Matter ◽  
Steady State ◽  
Soil Organic Matter ◽  
Priming Effect ◽  
Deep Soil ◽  
Fresh Organic Matter ◽  
Decomposition Models ◽  
Decomposer Community ◽  
Som Decomposition

Abstract. Decomposition of soil organic matter (SOM) is limited by both the available substrate and the active decomposer community. The understanding of this colimitation strongly affects the understanding of feedbacks of soil carbon to global warming and its consequences. This study compares different formulations of soil organic matter (SOM) decomposition. We compiled formulations from literature into groups according to the representation of decomposer biomass on the SOM decomposition rate a) non-explicit (substrate only), b) linear, and c) non-linear. By varying the SOM decomposition equation in a basic simplified decomposition model, we analyzed the following questions. Is the priming effect represented? Under which conditions is SOM accumulation limited? And, how does steady state SOM stocks scale with amount of fresh organic matter (FOM) litter inputs? While formulations (a) did not represent the priming effect, with formulations (b) steady state SOM stocks were independent of amount of litter input. Further, with several formulations (c) there was an offset of SOM that was not decomposed when no fresh OM was supplied. The finding that a part of the SOM is not decomposed on exhaust of FOM supply supports the hypothesis of carbon stabilization in deep soil by the absence of energy-rich fresh organic matter. Different representations of colimitation of decomposition by substrate and decomposers in SOM decomposition models resulted in qualitatively different long-term behaviour. A collaborative effort by modellers and experimentalists is required to identify appropriate and inappropriate formulations.

scholarly journals Modeling rhizosphere carbon and nitrogen cycling in <i>Eucalyptus</i> plantation soil

2018 ◽  
Vol 15 (16) ◽  
pp. 4943-4954 ◽  
Author(s):  
Rafael Vasconcelos Valadares ◽  
Júlio César Lima Neves ◽  
Maurício Dutra Costa ◽  
Philip James Smethurst ◽  
Luiz Alexandre Peternelli ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Root Growth ◽  
Priming Effect ◽  
Model Performance ◽  
N Cycling ◽  
Eucalyptus Plantation ◽  
Eucalyptus Plantations ◽  
C And N ◽  
C And N Cycling

Abstract. Vigorous Eucalyptus plantations produce 105 to 106 km ha−1 of fine roots that probably increase carbon (C) and nitrogen (N) cycling in rhizosphere soil. However, the quantitative importance of rhizosphere priming is still unknown for most ecosystems, including these plantations. Therefore, the objective of this work was to propose and evaluate a mechanistic model for the prediction of rhizosphere C and N cycling in Eucalyptus plantations. The potential importance of the priming effect was estimated for a typical Eucalyptus plantation in Brazil. The process-based model (ForPRAN – Forest Plantation Rhizosphere Available Nitrogen) predicts the change in rhizosphere C and N cycling resulting from root growth and consists of two modules: (1) fine-root growth and (2) C and N rhizosphere cycling. The model describes a series of soil biological processes: root growth, rhizodeposition, microbial uptake, enzymatic synthesis, depolymerization of soil organic matter, microbial respiration, N mineralization, N immobilization, microbial death, microbial emigration and immigration, and soil organic matter (SOM) formation. Model performance was quantitatively and qualitatively satisfactory when compared to observed data in the literature. Input variables with the most influence on rhizosphere N mineralization were (in order of decreasing importance) root diameter > rhizosphere thickness > soil temperature > clay concentration. The priming effect in a typical Eucalyptus plantation producing 42 m3 ha−1 yr−1 of shoot biomass, with assumed losses of 40 % of total N mineralized, was estimated to be 24.6 % of plantation N demand (shoot + roots + litter). The rhizosphere cycling model should be considered for adaptation to other forestry and agricultural production models where the inclusion of such processes offers the potential for improved model performance.

scholarly journals Soil Restoration Practices Effects on Priming Effect Intensity and Carbon Fluxes

2021 ◽  
Author(s):  
Abdourhimou Amadou Issoufou ◽  
Bachirou Hamadou Younoussa ◽  
Sabiou Mahamane ◽  
Idrissa Soumana ◽  
Garba Maman ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Priming Effect ◽  
Critical Role ◽  
Carbon Fluxes ◽  
Soil Restoration ◽  
Strong Impact ◽  
Priming Effects ◽  
C Cycle ◽  
Restoration Practices

Abstract BackgroundThe decomposition of soil organic matter (SOM) is one of the most important processes influencing the global carbon (C) cycle, the physico-chemical characteristics of soils, the mineralization of nutrients for plant growth and soil food webs. Yet, priming effects are considered to be large enough to influence ecosystem carbon fluxes. Here we have tested the effects of soil restoration practices on priming effect and carbon fluxes.ResultOur results suggest that indirect effects are such as altered stabilization of older C associated with the increased inputs of fresh plant inputs (‘priming’) add uncertainty to the prediction of future soil C responses. Far ahead restoration influence the amount and composition of the decomposer organisms, including soil fauna, as well as the soil microbial community, by inducing up to more CO2 emission with fresh millet straw addition in fresh state than pre-decomposed one. Restoration had a very strong impact (increase by 22.7%) on basal soil organic matter mineralization but not on priming effect. The PE of non-restored site was lower than that of restored site by 14.9–22.7%; the lowest mineralization per unit carbon was recorded in the non-restored. Through the “4 per 1000” initiative, it has been very recently demonstrated that priming effect could have a noticeable impact on soil carbon sequestration. ConclusionWe have shown in our study that the degraded soil played a dominant positive role in the soil organic carbon mineralization. Our results provide solid evidence that SOC content plays a critical role in regulating apparent priming effects, with important implications for the improvement of C cycling models under global change scenarios.

scholarly journals Colimitation of decomposition by substrate and decomposers – a comparison of model formulations

2008 ◽  
Vol 5 (3) ◽  
pp. 749-759 ◽  
Author(s):  
T. Wutzler ◽  
M. Reichstein
Keyword(s):  
Organic Matter ◽  
Steady State ◽  
Soil Organic Matter ◽  
Priming Effect ◽  
Deep Soil ◽  
Fresh Organic Matter ◽  
Decomposition Models ◽  
Decomposer Community ◽  
Som Decomposition

Abstract. Decomposition of soil organic matter (SOM) is limited by both the available substrate and the active decomposer community. The understanding of this colimitation strongly affects the understanding of feedbacks of soil carbon to global warming and its consequences. This study compares different formulations of soil organic matter (SOM) decomposition. We compiled formulations from literature into groups according to the representation of decomposer biomass on the SOM decomposition rate a) non-explicit (substrate only), b) linear, and c) non-linear. By varying the SOM decomposition equation in a basic simplified decomposition model, we analyzed the following questions. Is the priming effect represented? Under which conditions is SOM accumulation limited? And, how does steady state SOM stocks scale with amount of fresh organic matter (FOM) litter inputs? While formulations (a) did not represent the priming effect, with formulations (b) steady state SOM stocks were independent of amount of litter input. Further, with several formulations (c) there was an offset of SOM that was not decomposed when no fresh OM was supplied. The finding that a part of the SOM is not decomposed on exhaust of FOM supply supports the hypothesis of carbon stabilization in deep soil by the absence of energy-rich fresh organic matter. Different representations of colimitation of decomposition by substrate and decomposers in SOM decomposition models resulted in qualitatively different long-term behaviour. A collaborative effort by modellers and experimentalists is required to identify formulations that are more or less suitable to represent the most important drivers of long term carbon storage.

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