Deficit and Recovery of Deep Soil Water Following a Full Cycle of Afforestation and Deforestation of Apple Trees on the Loess Plateau, China

Round 1

Reviewer 1 Report

Dear Authors,

Although it is a re-submitted manuscript, I was evaluating it as a new submission only with respect to my previous concerns.

The manuscript describes an interesting research dealing with soil water content changes with respect to the age of the apple tree orchard; monitoring and describing the increasing soil water deficit in deeper soil layers with increasing age of the apple tree and its reduction after felling the trees. The title describes the main objectives of the study and the manuscript is easy to follow. It is also clearly written, what has already been published and what is new in the manuscript (which was my main concern in the previous submissions). There are some new, nice and illustrative figures (Fig. 2 and and 4). However, I have a list of comments, which, in my opinion need to be addressed before publishing.

Comments and requests for revisions:

The section “Materials and methods” needs to be revised, it needs to be clear, how the data were treated (description of applied statistics is completely missing – data normality test? what kind of statistical tests was used?). I would prefer to use “gravimetry with oven drying” for water content determination, rather than “oven-dry-method” on line 118 (also a reference to the method should be mentioned).  (No indication of the texture classification of the experimental site can be found, although it is mentioned on line 122. Line 129 (explanation of variables in Eq.1) TD and TR (mm) is it cumulative deficit and replenishment CD and CR or something different?  The “space-to-time” method has been presented earlier than 2018, usually the reference is from 1989 (Pickett STA (1989) Space-for-time substitution as an alternative to long-term studies. In: Likens GE, editor. Long-Term Studies in Ecology: Approaches and Alternatives. New York, Berlin: Springer-Verlag. 110–135.)    The section “Results” needs rearrangement/revision. It is strange to start the result section with a figure without any overall description or summary of the collected and evaluated data. The headings in Tab.1 and Tab.2 should be in bold. The probability value p within Tab. 1 is written as “P” instead of “p”. A lot of formal mistakes:  Different writing style and spacing within the manuscript (not following the template), Template from 2019 has been used – please update the footer Not following the guidelines for references: full titles of journal names are often used, References [19] and [36] are the same and also [55] and [57] (no p. 201800141 exists within this paper), Ref. 40 should be cited properly – Methods of soil analysis is a book with its own citation form (if it is cited in a journal, it needs to be clear from the citation…), Ref. 42 Hydrological Processes is a name of the journal.

As a conclusion, I recommend to accept the manuscript for publication after minor revision.

Kind regards,

Your reviewer

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

General comments:

This is a well-designed study that presents convincing results. The findings have important implications for sustainable water resource and land management strategies in the Loess Plateau of China. There are many minor grammatical errors because the English language is difficult! I provided a non-comprehensive list of suggested corrections, and recommend the authors seek help from an English language expert or native speaker to improve the grammar as a whole. Regarding the science, I only raised a few minor concerns in my comments which I expect the authors to address.

Abstract:

Line 17:  Clarify ‘deep’ in meters

Line 21: Reword for clarity. E.g. “…soil water quickly recovered to pre-depletion soil water content in the upper 7 m in the first two years…

Introduction:

Line 53: remove ‘to’

Line 65 add ‘s’ to plant

Methods:

It would be useful to the reader to provide an explanation and possibly an equation on how ‘recovery depth’ is calculated.

Section 2.2. first paragraph – ‘studies’ or ‘investigations’ are better terms than ‘researches’

Line 92: investigate the …

Line 124: “space-for-time” is the common phrasing

Line 129 TD and TR should be defined

Results:

Line 152 spelling error – content. Rewording suggestion that uses action verb: “Soil water content slightly increased…”

Lines 156-162: Table 1 indicates that 8 yo and 11 yo increases in soil moisture are not significant at P < 0.01. Are these results significant at P < 0.05? Please clarify. Consider presenting the same confidence level in Table 1 and the written results.

Line 179-180:This statement appears incorrect – the CD vs. stand age is a slightly stronger correlation than CD vs. dW. However, these correlation coefficients are so close that any speculation as to why one is stronger is than the other is not justifiable (Lines 180-181). Please address.

Discussion:

204: Suggested rewording to “young sapling transpiration was less than annual crop transpiration”

208: reword cumulated to accumulated

213: Consider rewording, eg deep roots taking up

213: Does the water infiltration velocity assume 100% piston flow and 0% preferential flow? Consider preferential flow as a possible mechanism in loess soils e.g. Li et al., 2017. Preferential flow assumptions should generally be addressed in the paper.

214: Please clarify what ‘finally extended to 23.2 m’. The roots? Consider changing the single sentence into multiple sentences.

243-244: Consider citing relevant studies on land cover and infiltration characteristics.

Conclusion:

Lines 299-300. However, your study also showed how cumulative deficit related to tree age, which would not necessarily relate to drought. I suggest you show how the cumulative deficit vs. ET0 is a poorer predictor than cumulative deficit vs (Precipitation – ET0) in order to strengthen your claim that that drought was a driving force. Otherwise I suggest removing the statement ‘…indicating that drought was a driving force for apple trees to absorb deep soil water’.

References:

Line 362 Missing ‘J.’ – J.J. McDonnell

Line 392: ZHANG should not be all caps

Lines 451-456: #55 and #57 are duplicate citations.

Citations:

Li, Z., Chen, X., Liu, W., & Si, B. (2017). Determination of groundwater recharge mechanism in the deep loessial unsaturated zone by environmental tracers. Science of the Total Environment, 586, 827-835.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The topic of the manuscript is interesting and has wider policy and management implications. Overall, the structure and organization of the contents are acceptable. The methods section, however, requires further improvement. I understand that this is part of a larger and long term study in that region by the authors and they already published several other works from that. I would, therefore, encourage authors to briefly describe their overall goals and objectives, protocols for data collection and key previous findings. The figures used in the study are not very high quality and need to be improved.

Some minor comments/suggestion below:
page 1, in the title, mention the location of the study (i.e. Loess Plateau, China);
page 1, line 33-34: mention some species here;
page 1, line 34-35: provide relevant reference(s);
page 2, line 46: provide the scientific name when first used;
page 3, Figure 1: provide a larger and better quality study area map;
page 9, line 268: I would suggest using 'management' instead of 'development' here';
page 9, line 282-290: consider placing this section in the methods part;

The manuscript would be also benefitted if checked by a native English speaker or a professional editor.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Review of "Deficit and recovery of water from deep Loess soil in an orchard"

 

General: Most of the issues are now addressed. See a few minor issues below.

 

Specific

L. 78: "Because the Loess Plateau is aolian"

L. 79-80: "Groundwater in the region is more than 50 m deep"

Figure 1: All the main text is now large enough; however, I still cannot read the insert in (a).

Tables 1, 2: Work to keep each Table on one page by using "insert page break" at the start of the Table. They are hard to read when they cross pages.

L. 206-207: "... because the deep roots took up water before it could infiltrate further into the soil."

Reviewer 2 Report

Dear Authors and Editors,

The resubmitted manuscript shows improvements; aims and objectives have been formulated, newer references have been added, some statistics was presented within the results, some mistakes and inconsistencies have been corrected. Some formal mistakes still need to be sorted: e.g. journal abbreviated titles are not used in all relevant references, et al. appearance within the list of references after the fifth author – lines 319 and 407, in-text citations on lines 122 and 260

Apart from the above written, I need to express my concern dealing with the soil moisture data originality presented in the manuscript.Naturally, the research can be part of a large study and the results can be published in different papers, but it always needs to be clear what has already been published and what is new in the manuscript considered for publication. I asked specifically to make this clear in the previous review, but, in my opinion, this concern was not sorted out.  

Manuscript under consideration renamed to “Deficit and recover of water from deep Loess soil in an orchard” ,in the part dealing with the soil moisture monitoring, is very similar to the paper of Zhang, Z., M. Li, B. Si, and H. Feng “Deep rooted apple trees decrease groundwater recharge in the highland region of the Loess Plateau, China” published in 2018 in Science of The Total Environment, 622-623: p. 584-593).

Apparent similarities: same GPS location of the experimental areas, Figure 1 and Figure 2, soil sampling procedure (lines 100-107),but also similarities within results and discussion section, where I expected original research data if there is no reference next to it – but I did find almost the same sentences incl. numbers: e.g. elevated soil moisture contents due to calcareous concretions in a certain depth described in lines 219-221, or lines 138-139 about vertical variations in soil water. These are just examples I was able to identify within a short time.

After reading both papers carefully, I had the impression, that only the part dealing with soil moisture recovery after felling the orchard is original. That is why I can not recommend the resubmitted manuscript for publication.

The manuscript itself is very nice, so if you can explain these similarities or rewrite the manuscript in a way, that you cite already published data and present the new unpublished data, I would be happy to recommend it for publication.

Kind regards,

Your reviewer