Estimates of mean residence times of phosphorus in commonly considered inorganic soil phosphorus pools

Helfenstein, Julian; Pistocchi, Chiara; Oberson, Astrid; Tamburini, Federica; Goll, Daniel S.; Frossard, Emmanuel

doi:https://doi.org/10.5194/bg-17-441-2020

Articles | Volume 17, issue 2

https://doi.org/10.5194/bg-17-441-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-17-441-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 17, issue 2

Research article

|

30 Jan 2020

Research article |

| 30 Jan 2020

Estimates of mean residence times of phosphorus in commonly considered inorganic soil phosphorus pools

Julian Helfenstein, Chiara Pistocchi, Astrid Oberson, Federica Tamburini, Daniel S. Goll, and Emmanuel Frossard

Download

Final revised paper (published on 30 Jan 2020)
Supplement to the final revised paper
Preprint (discussion started on 26 Aug 2019)
Supplement to the preprint

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

- Printer-friendly version

- Supplement

RC1: 'Review', Anonymous Referee #2, 30 Aug 2019
- AC1: 'short reply to reviewer comment', Julian Helfenstein, 04 Sep 2019
- AC2: 'final response to referee1', Julian Helfenstein, 06 Nov 2019
RC2: 'Comments to the authors', Enqing Hou, 30 Sep 2019
- AC3: 'author response', Julian Helfenstein, 06 Nov 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (08 Nov 2019) by Edzo Veldkamp

Dear Dr. Helfenstein and colleagues,
I have now read your manuscript again and the interesting discussion following the points raised by the reviewers. Phosphorus is a very important nutrient that is notoriously hard to study, because of the multiple inorganic and organic pools in which it occurs in soils. In addition, the available P isotopes are both radioactive and have a short life time, which adds to the complications of studying P. I therefore welcome this study in which Isotope exchange kinetic experiments are linked to pools obtained in the commonly used sequential Hedley extractions. There is no doubt that making this link is partly controversial (see the critical points raised by the reviewers), and I share some of the concerns voiced by the reviewers, especially the derivation of MRT from short term IEK experiments and the problem of linking laboratory measurements to field conditions. However, as it is IEK experiments cannot be conducted under field conditions and for the MRT estimates you acknowledge the shortcomings of your approach and you provide independent evidence hat largely support your assessments. I share your concern that the representations of soil phosphorus dynamics are currently very rudimentary in land surface models. I would like to add that this is not only true for phosphorus, but that even the representation of soil nitrogen and carbon dynamics in soils is not up to date. There is clearly a need for more communications of the experimental and modelling communities.
I invite you to upload the revised version of your manuscript, that addresses the concern voiced by the reviewers. I will decide whether I will send it out for review, after I have read the revised version.

Edzo Veldkamp

Hide

AR by Julian Helfenstein on behalf of the Authors (15 Nov 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (22 Nov 2019) by Edzo Veldkamp

RR by Enqing Hou (30 Nov 2019)

Suggestions for revision or reasons for rejection

I am generally happy at the authors' responses and revisions. Following are a few topics that are open to discuss, which are largely of my personal opinion.
(1) I agree that practically solution P can exchange with HCl-P in not only acidic soils but also neutral and alkaline soils. However, the way the authors showed in Fig. 1a is misleading. Fig. 1a suggests that solution P is totally exchangeable with HCl-P, which is not true. I would suggest that the arrow from resin P to HCl-P should be shorter than that from HCl-P to resin P, and explain the settings: exchangeable but the net flow is from HCl-P to resin P (rephrase it).
(2) The calculation of MRT of NaOH-P and HCl-P still puzzle me. If possible, MRT of NaOH-P (or HCl-P) should be calculated as the MRT of NaOH fraction (or HCl-P fraction), not the sum of resin P and NaOH fraction (or HCl fraction). If calculated in the current way, the estimated MRT would be not directly comparable with the MRT used in processes-based models (i.e., MRT of each fraction). If it is impossible to calculate the MRT of individual fraction, the authors may note the problem of comparing with processes-based models.
(3) The authors should be cautious about the statement "current LSM largely overestimate MRTs of P in inorganic P pools" and their comparison with LSM (Table 3). Because LSM typically simulate soil P dynamics in field stations, while the estimates here are under laboratory conditions. I am not surprise to see results in Table 3. Table 3 does not necessarily means "current LSM largely overestimate MRTs of P in inorganic P pools". So, the authors should make readers aware of the differences under laboratory vs. field conditions.
(4) In acknowledgements, "Enquing" should be "Enqing".

Hide

ED: Publish subject to minor revisions (review by editor) (09 Dec 2019) by Edzo Veldkamp

AR by Julian Helfenstein on behalf of the Authors (20 Dec 2019) Author's response Manuscript

ED: Publish as is (08 Jan 2020) by Edzo Veldkamp

AR by Julian Helfenstein on behalf of the Authors (10 Jan 2020)

Download

Article (1117 KB)
Full-text XML

Short summary

In this article we provide estimates of mean residence times of phosphorus in inorganic soil phosphorus pools. These values improve our understanding of the dynamics of phosphorus cycling and can be used to improve global land surface models.