New publication in Biogeosciences: Soil solution phosphorus turnover: derivation, interpretation, and insights from a global compilation of isotope exchange kinetic studies.

Helfenstein et alAbstract. The exchange rate of inorganic phosphorus (P) between the soil solution and solid phase, also known as soil solution P turnover, is essential for describing the kinetics of bioavailable P. While soil solution P turnover (Km) can be determined by tracing radioisotopes in a soil–solution system, few studies have done so. We believe that this is due to a lack of understanding on how to derive Km from isotopic exchange kinetic (IEK) experiments, a common form of radioisotope dilution study. Here, we provide a derivation of calculating Km using parameters obtained from IEK experiments. We then calculated Km for 217 soils from published IEK experiments in terrestrial ecosystems, and also that of 18 long-term P fertilizer field experiments. Analysis of the global compilation data set revealed a negative relationship between concentrations of soil solution P and Km. Furthermore, Km buffered isotopically exchangeable P in soils with low concentrations of soil solution P. This finding was supported by an analysis of long-term P fertilizer field experiments, which revealed a negative relationship between Kmand phosphate-buffering capacity. Our study highlights the importance of calculating Km for understanding the kinetics of P between the soil solid and solution phases where it is bioavailable. We argue that our derivation can also be used to calculate soil solution turnover of other environmentally relevant and strongly sorbing elements that can be traced with radioisotopes, such as zinc, cadmium, nickel, arsenic, and uranium.

For the full text please follow the link:

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Phylogenetic distribution, biogeography and the effects of land management upon bacterial non-specific Acid phosphatase Gene diversity and abundance


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Structural equation modeling for the estimation of interconnections between the P cycle and soil properties

Marcus Nutrient cycling titleMarcus Nutrient Cycling

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Symposium on Phosphorus in Plants and Soils (10-13th September 2018).

We would like to announce The Symposium on Phosphorus in Plants and Soils. The symposium will be held from 10-13 September 2018 in Leuven and will be hosted by the KU Leuven. More information is available at the website: www.psp6symposium.comIf you have more questions, you can contact Kris Dox ( or Erik Smolders ( , who is the chair of the organizing committee.
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New Administrator

I would just like to say a quick hello as the new administrator of the soil phosphorus forum. If you have any posts or requests please get in touch.

Many thanks


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Doctoral and postdoctoal opportunities at Environmental Biogeochemistry Laboratory at the University of Delaware

The Environmental Biogeochemistry Laboratory ( at the University of Delaware has openings for two graduate students and a postdoctoral researcher. A short description of the positions and benefits is included below:

  1. Graduate students
  2. i) Source tracking of phosphorus in a watershed. It requires general background in soil chemistry, biogeochemistry, and watershed scale processes. Experience on stable isotopes (P and N) or nutrient cycling in a watershed is a plus.
  3. ii) Residual and recalcitrant phosphorus in soil. It requires background on soil sciences/chemistry, geochemistry or related discipline.

Candidates are for PhD degree. A 12-month research assistantship of ~$25,000 will be paid to graduate students. Graduate application has be made through UD ( Successful candidates are anticipated to start late summer or Fall.

  1. Postdoctoral associate 

Fate of phytate in the environment. Phytate and other inositol phosphates in soils: detection, quantitation, and degradation and address the longstanding question on accumulation vs decomposition of phytate in the environment. A recent Ph.D. in soil sciences, chemistry or related discipline from an accredited university is required. Candidate must have knowledge and experience in one or more of the following research techniques: ion chromatography, stable isotopes, 1 and 2-D NMR spectroscopy, stereochemistry, and enzymology, and a proven record through scientific publications. Candidate must be willing to learn other research technique from his/her own expertise.

A 12-month salary of $48,000 will be paid to the postdoctoral associate. University of Delaware offers a generous health insurance and other benefits.  See for complete details of the benefit package.

Interested candidates for both positions are advised to contact Deb Jaisi ( for further information.

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9th International Symposium on Ecosystem Behavior

August 20-24, 2017
Litomyšl Chateau, Czech Republic

You are cordially invited to BIOGEOMON 2017, to be held next summer at the UNESCO World Cultural Heritage Site of Litomyšl, Czech Republic.

The symposium will focus on biogeochemistry in an era of global change. Long-term trends in ecosystem functioning and stoichiometry of biogeochemical processes in upland and wetland soils will be emphasized, along with catchment monitoring/modelling, and translocations of nutrients, micronutrients and trace metals in forest ecosystems, grasslands and extreme environments. We look forward to seeing you in the lovingly restored 16th century town of Litomyšl.


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Studentship opportunity: organic phosphate cycling in soils

The biodiversity of organic phosphate (phytate) cycling in soils (BREARLEY_UBIO17EE) – CASE studentship with AB Vista/AB Enzymes

 Project Supervisor: Dr Charles Brearley (

School of Biological Sciences, University of East Anglia

Project description (more information here)

Phytate (inositol hexakisphosphate) is one of the most abundant organic phosphates in the environment and is of great importance to the global P-cycle. Synthesized by plants, the amount harvested in beans, grains, tubers and other organs is equivalent to the amount of phosphate fertilizer applied to soils per annum. That not harvested enters soils where it undergoes biological and geochemical transformations. We do not know which organisms are responsible for recycling phytate phosphate in the environment, it likely depends on the soil type, but we have strong evidence that microbial phytases are responsible.

Project aims
To study the role of bacteria in phytate/phosphate recycling in soils, particularly to identify the species and the enzymes they express that are responsible for phytate recycling, and so to provide lead enzymes for our industrial partner’s next generation phytase discovery programmes.

Shortlisted applicants will be interviewed on 14/15 February 2017.

Successful candidates who meet RCUK’s eligibility criteria will be awarded a NERC studentship. In most cases, UK and EU nationals who have been resident in the UK for 3 years are eligible for a full award. In 2016/17, the stipend was £14,296.

  • Start date October 2017
  • Programme PhD
  • Studentship Length 3.5 years

more information here

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Phosphorus – ESPP video

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PhD position at VITO- Quantification of phosphorus flux

Early Stage Researcher (PhD) Fellowships – ESR1, Quantification of phosphorus fluxvito
The Flemish Institute for Technological Research (VITO) calls for candidates for a PhD-position available from October 2016 onwards. The fellowship “Quantification of phosphorus flux” is available within the INSPIRATION Marie Skłodowska-Curie Innovative Training Network.Further information and the full terms and conditions regarding eligibility are provided on Work Programme 2014-2015.

Application process

Candidates should provide the following information before August 15 in one file for their application :
1. A detailed CV with covering letter which explains your suitability, competence and motivation for scientific research and the fellowship
2. All undergraduate level certificates including university grades. Foreign documents should be sent as certified English translations.
3. A summary of technical and scientific experience
4. A synopsis of the undergraduate/Master’s level thesis if applicable, or a detailed description of any previous research project and its appropriate work plan
5. A list of publications and/or presentations at meetings, if applicable
6. Contact information of two referees
Applications should be addressed by email to: Ingeborg Joris ( and in cc to Ilse Van Keer (
Additional information
Further information on other fellowships available within the INSPIRATION Marie Skłodowska-Curie Innovative Training Network can be found on Further information on the INSPIRATION project and consortium partners can be found on

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