What Do Plants Leave after Summer on the Ground?—The Effect of Afforested Plants in Arid Environments

Round 1

Reviewer 1 Report

moderate revisions are needed to improve the paper soundness.

please find the suggestions in the attached file

Comments for author File: Comments.docx

Author Response

In the attached file are the replies for each of the comments and recommendations.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript indicates the vegetation (Willow and Salix) influence on the soil water conditions in semi-arid continental climatic region. The objective of the study is interesting. However, the structure and content of the manuscript are not well organized and need to be improved.

Abstract

Better to strengthen the abstract by embedding the main results.

Precipitation values can take out.

Main conclusions are missing

 Introduction

Not strongly oriented towards the main question of the study

Should be streamlined

Line 25: Please give a reference

Lack of literature review and information about previously used methods

Authors need to indicate why did they select these methods? What is the advantage over other methods? (e.g isotope method, IsoSource model, etc.)

 Materials and methods

This section needs to be more detailed

Line 74: these values for which year?

If this is for the experimental year, why is it different from the values in the results section?

Line 76: ‘high base saturation’. Not clear

Line 75-76: Are these values from the reference? Not clear

 Figure 1: The text on the right side figures are too small.

Please give units for all the parameters mentioned.

Line 92: es and ea are not explained.

Please mention the values assigned for the parameters in equation 3.

From where did you measure the groundwater level?

Line 99-100: What do you mean by data collected corresponded to groundwater level and soil moisture?

Line 103: Soil water content is the same term for soil moisture? Please be consistent  

Line 106: The sentence is not clear.

Line 109: ‘Water samples were collected daily after each rain event..’: there is no daily rain. Isn’t it? Were samples takes only on rainy days?

When you indicate interments, please give more details such as manufacture, etc.

Units are missing for the eq. 2. You do not need an equation here, it can be added to the text instead.

Line 133: Why there is a difference in measuring the area? Better to have an explanation.

Line 134: The area mentioned by ‘274.61 cm2’ is for which tree?

Line 138: Temperature difference of what? Maximum temperature of what? Not clear

The authors need to explain more about how did they use the IsoSource method.

Your plant samples are not overlapping completely with soil water, so how did you apply the model successfully?

Results

The authors have not mentioned the statistical differences between different source (isotopic values, soil moisture, 3 different soil groups, etc.)

Line 160-162: Sentence is confusing, please restructure

Line 164: Experienced what?

Line 179-180: Please mention for what those numbers are referred to.

Could the authors mark the groundwater isotopic signature in figure 5?

Line 183: For Salix, it is at 20 cm. isn’t it?

Line 185-186: The authors have started the sampling from 10 cm, therefore it is unacceptable comparing above 10 cm.

How deep are the roots of both plants?

Line 187-188: Based on what the authors made this statement?

Line 191-193: The argumentation for the grouping is not clear.

Did the authors add additional information such as RLD and TRB to the IsoSource model? Is there a possibility?

Is there a significant difference between the contributions?

Presenting the results of figure 6 is not clear and complete.

Could the authors supply the isotopic data in a dual isotopic plot (from all the water sources mentioned in fig. 5).

Figure 5: The evaporation front is not marked in the plot. Soil water isotopic profile is more suitable than naming the figures as evaporation front because the authors show not only the evaporation front. The figure caption should be more detailed.

Figure 6: Please indicate the short forms in the figure caption too. Why there is a scale difference in the plots on the right side (frequencies)?

Discussion

The discussion is not strong and supported by the results. There is no connection between paragraphs and the facts are not clearly driven to an overall goal. Need to restructure.

Your results should be comparable to other studies.

Add references to the places where it is necessary (e.g. line230-231)

Lack of references

Line 215: Groundwater isotopic values are not given.

Is the reference 50 represent the same area? If not, are the conditions similar to your study site?

Line 226: soil water isotopic composition is only affected by these 2 factors? There can be many more. For example redistribution, hydraulic lift, isotopic signature of the input water, etc.. and please give references to confirm.

Line 228-229: How much is the soil moisture difference in the topsoil? Following fig. 3 there is not much difference until 40 cm.

Line 230-231: Please indicate specifically where (below at which depth)?

Line 233: ‘the signature..’, signature of what?

Lien 233-237: It is not clear what the authors want to highlight

Anyway, your sampling intervals are high and only because of that it is hard to come to conclusions about the evaporation front. Is there a significant difference between the isotopic profiles of both plants?

Line 244-245: By which results this argumentation is supported? Extracted uniformly? There is a mismatch with the line 199-200.

Line 261: Do you have a seasonal comparison/ data for both seasons?

Line 267: ‘proposed by …’. please write the name of the Author.

Line 274: Plant water uptake is a non-fractionated process. Please give a reference here.

Conclusion

Need to restructure and clear with the objective. The conclusions should be based on your findings. The first part of it is too general. The novelty of the results is not highlighted.

Author Response

The answers to the comments and suggestions are listed in the attached pdf.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thank you for your corrections and explanations. I've found them very clear and exhaustive.

Only few comments on the results/discussion chapters, about isotopes and level of groundwater

1) "An idea of the groundwater level excursion would be better...."

I meant that groundwater level measurements in different points of the year would be of interest: please add in the text a range of values of groundwater table during the year

2) okay for the new plots on isotopes, I suggest, however, to add in the text a range of isotope values about groundwater

Author Response

Reply to First Reviewer-Second Round

In blue we copied the comments of the reviewer, in black our reply. All the references to the lines done by the authors are from the re-submitted manuscript.

Thank you for your corrections and explanations. I've found them very clear and exhaustive.

Only few comments on the results/discussion chapters, about isotopes and level of groundwater

1) "An idea of the groundwater level excursion would be better...."

I meant that groundwater level measurements in different points of the year would be of interest: please add in the text a range of values of groundwater table during the year

Reply: the groundwater data available for the experimental site comprises the period between 21-08-2010 to 20-04-2011. During this period, the groundwater oscillates between 136.3 cm to 163.8 cm depth in Salix psammophila and between 149.4 cm to 172.3 cm depth in Salix matsudana. Following the reviewer’s recommendation, we added the following sentence in Line 133:

“... in each plot. Groundwater depth from the surface in both plots oscillates between 136 cm to 164 cm beneath the Willow bush plot and between 150 cm to 172 cm beneath Willow tree plot (period between 21-08-2010 to 20-04-2011).”

2) okay for the new plots on isotopes, I suggest, however, to add in the text a range of isotope values about groundwater

Reply: we added these values in Lines 229-230 as follow:

“... isotopes (Figure 5). The isotope signature of groundwater samples (Willow Bush: δ¹⁸O: -9.2‰, δ²H: -66.1‰ and Willow Tree: δ¹⁸O: -8.59‰, δ²H: -60.66‰) lie close to the rain water signature,  depicting the ...”

Reviewer 2 Report

I still do not see a clear improvement in the abstract and conclusion. In the abstract why don’t the authors mention the main results of water extraction by plants? Total precipitation is an observation and not something to indicate in the abstract. The abstract should be the cream of your research.

In conclusion, the authors focus on roots and water extraction by plants while in the abstract (results section) on transpiration. I see therefore a mismatch/unclear storyline. Please develop a clear story and strengthen it with your results.

'From where did you measure the groundwater level?'

Reply: see within Figure 1 (map), the blue triangles within each of the plot designs.

Here the unclear point is from where did you measure the GW level? from a well or from soil pits ..etc? It is better to include this info in the manuscript

Could the authors name the possible solution in figure 6 caption? It is not clear enough what is meant by all possible solutions.

Sometimes authors use Salix and sometimes Willow bush. Please be consistent. Indicate two terms that you want to use clearly at the beginning and then use it throughout the manuscript.

There are some differences in figure 5 in version 1 and 2. For rainwater isotopic values you have a different range for 2H in v1 and v2. Why is that?

Authors say “..On the other hand, beneath Willow bush only the d18O profile shows the theoretical evaporation front. The homogeneity of d2H beneath Willow bush indicates a recent redistribution of groundwater along with the soil profile, which can be linked to hydraulic lift processes carried out by this bush. “

How do the authors make this conclusion only with this observation? In contract, there is a difference of the 2H profile of Salix with figure 5 in v1. In v1, we could observe this evaporation front for 2H as well.

It is better if the authors can mention (direct the reader to) fig.A3 in the main text. 

Author Response

Thanks for the comments and suggestions.

The reply to each of them can be found in the attached file.

Author Response File: Author Response.pdf