scholarly journals Multi-isotope labelling (<sup>13</sup>C, <sup>18</sup>O, <sup>2</sup>H) of fresh assimilates to trace organic matter dynamics in the plant-soil system

2014 ◽  
Vol 11 (11) ◽  
pp. 15911-15943
Author(s):  
M. S. Studer ◽  
R. T. W. Siegwolf ◽  
M. Leuenberger ◽  
S. Abiven
Keyword(s):  
Organic Matter ◽  
Populus Deltoides ◽  
Terrestrial Ecosystems ◽  
Leaf Water ◽  
Water Soluble ◽  
Soil System ◽  
Isotope Labelling ◽  
Plant Soil ◽  
Elemental Cycling ◽  
Isotope Technique

Abstract. Isotope labelling is a powerful tool to study elemental cycling within terrestrial ecosystems. Here we describe a new multi-isotope technique to label organic matter (OM). We exposed poplars (Populus deltoides x nigra) for 14 days to an atmosphere enriched in 13CO2 and depleted in 2H218O. After one week, the water-soluble leaf OM (δ13C = 1346 ± 162‰) and the leaf water were strongly labelled (δ18O = −63± 8‰, δ2H = −156 ± 15‰). The leaf water isotopic composition was between the atmospheric and stem water, indicating a considerable diffusion of vapour into the leaves (58–69%). The atomic ratios of the labels recovered (18O/13C, 2H/13C) were 2–4 times higher in leaves than in the stems and roots. This either indicates the synthesis of more condensed compounds (lignin vs. cellulose) in roots and stems, or be the result of O and H exchange and fractionation processes during transport and biosynthesis. We demonstrate that the three major OM elements (C, O, H) can be labelled and traced simultaneously within the plant. This approach could be of interdisciplinary interest for the fields of plant physiology, paleoclimatic reconstruction or soil science.

scholarly journals Multi-isotope labelling of organic matter by diffusion of <sup>2</sup>H/<sup>18</sup>O-H<sub>2</sub>O vapour and <sup>13</sup>C-CO<sub>2</sub> into the leaves and its distribution within the plant

2015 ◽  
Vol 12 (6) ◽  
pp. 1865-1879 ◽  
Author(s):  
M. S. Studer ◽  
R. T. W. Siegwolf ◽  
M. Leuenberger ◽  
S. Abiven
Keyword(s):  
Organic Matter ◽  
Populus Deltoides ◽  
Terrestrial Ecosystems ◽  
Phloem Transport ◽  
Leaf Water ◽  
Water Soluble ◽  
Isotope Labelling ◽  
Elemental Cycling ◽  
Isotope Technique ◽  
Stem Water

Abstract. Isotope labelling is a powerful tool to study elemental cycling within terrestrial ecosystems. Here we describe a new multi-isotope technique to label organic matter (OM). We exposed poplars (Populus deltoides × nigra) for 14 days to an atmosphere enriched in 13CO2 and depleted in 2H218O. After 1 week, the water-soluble leaf OM (δ13C = 1346 ± 162‰) and the leaf water were strongly labelled (δ18O = −63 ± 8, δ2H = −156 ± 15‰). The leaf water isotopic composition was between the atmospheric and stem water, indicating a considerable back-diffusion of vapour into the leaves (58–69%) in the opposite direction to the net transpiration flow. The atomic ratios of the labels recovered (18O/13C, 2H/13C) were 2–4 times higher in leaves than in the stems and roots. This could be an indication of the synthesis of more condensed compounds in roots and stems (e.g. lignin vs. cellulose) or might be the result of O and H exchange and fractionation processes during phloem transport and biosynthesis. We demonstrate that the three major OM elements (C, O, H) can be labelled and traced simultaneously within the plant. This approach could be of interdisciplinary interest in the fields of plant physiology, palaeoclimatic reconstruction or soil science.

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 Soil and Plant Responses to Phosphorus Inputs from Different Phytase-Associated Animal Diets

Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 130
Author(s):  
Dario Fornara ◽  
Elizabeth M. E. Ball ◽  
Christina Mulvenna ◽  
Henry Reyer ◽  
Michael Oster ◽  
...  
Keyword(s):  
Organic Amendment ◽  
Water Soluble ◽  
Plant Responses ◽  
P Availability ◽  
Pig Slurry ◽  
Soil System ◽  
Soil P ◽  
Plant Soil ◽  
Soil Systems ◽  
P Content

The over-supplementation of animal feeds with phosphorus (P) within livestock-production systems leads to high rates of P excretion and thus to high P loads and losses, which negatively impact the natural environment. The addition of phytase to pig and poultry diets can contribute to reducing P excretion; however, cascading effects of phytase on plant–soil systems remain poorly understood. Here, we addressed how three different diets containing various levels of exogenous phytase, i.e., (1) no-phytase, (2) phytase (250 FTU), and (3) superdose phytase (500 FTU) for pigs (Sus scrofa domesticus) and broilers (Gallus gallus domesticus) might affect P dynamics in two different plant–soil systems including comfrey (Symphytum ×uplandicum) and ryegrass (Lolium perenne). We found that differences in phytase supplementation significantly influenced total P content (%) of broiler litter and also pig slurry (although not significantly) as a result of dietary P content. P Use Efficiency (PUE) of comfrey and ryegrass plants was significantly higher under the intermediate ‘phytase’ dose (i.e., commercial dose of 250 FTU) when compared to ‘no-phytase’ and ‘superdose phytase’ associated with pig slurry additions. Soil P availability (i.e., water soluble P, WSP) in both comfrey and ryegrass mesocosms significantly decreased under the intermediate ‘phytase’ treatment following pig slurry additions. Dietary P content effects on P losses from soils (i.e., P leaching) were variable and driven by the type of organic amendment. Our study shows how commercial phytase levels together with higher dietary P contents in pig diets contributed to increase PUE and decrease WSP thus making the plant–soil system more P conservative (i.e., lower risks of P losses). Our evidence is that dietary effects on plant–soil P dynamics are driven by the availability of P forms (for plant uptake) in animal excretes and the type of organic amendment (pig vs. broiler) rather than plant species identity (comfrey vs. ryegrass).

scholarly journals How big is the influence of biogenic silicon pools on short-term changes of water soluble silicon in soils? Implications from a study of a ten-year-old plant-soil-system

2017 ◽  
Author(s):  
Daniel Puppe ◽  
Axel Höhn ◽  
Danuta Kaczorek ◽  
Manfred Wanner ◽  
Marc Wehrhan ◽  
...  
Keyword(s):  
Water Soluble ◽  
Testate Amoeba ◽  
Short Term ◽  
Soil System ◽  
Plant Soil ◽  
Main Driver ◽  
Key Factor ◽  
Calamagrostis Epigejos ◽  
Biogenic Silicon ◽  
Soluble Silicon

Abstract. The significance of biogenic silicon (BSi) pools as a key factor for the control of Si fluxes from terrestrial to aquatic ecosystems has been recognized since decades. However, while most research has been focused on phytogenic Si pools, knowledge on other BSi pools is still limited. We hypothesized different BSi pools to influence short-term changes of the water soluble Si fraction in soils to different extents. To test our hypothesis we took plant (Calamagrostis epigejos, Phragmites australis) and soil samples in an artificial catchment in a post-mining landscape in the state of Brandenburg, Germany. We quantified phytogenic (phytoliths), protistic (diatom frustules and testate amoeba shells) and zoogenic (sponge spicules) Si pools as well as Tiron extractable and water soluble Si fractions in soils at the beginning (t0) and after ten years (t10) of ecosystem development. As expected the results of Tiron extraction showed, that there are no consistent changes of the amorphous Si pool at Chicken Creek as early as after ten years. In contrast, compared to t0 we found increased water soluble Si and BSi pools at t10, thus we concluded BSi pools to be the main driver of short-term changes of water soluble Si. However, because total BSi represents only small proportions of water soluble Si at t0 (

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