Effect of Bypass-Flow on Leaching of Salts in a Cracking Soil in the Nile Delta

Round 1

Reviewer 1 Report

The paper is interesting and worth to be published in an international journal. The paper lacks extensive discussion and its quality should be enhanced by introducing new references.

More detailed comments are incorporated in the annoted pdf file.

Comments for author File: Comments.pdf

Author Response

Reply to Reviewer 1

Thank you very much for having reviewed our manuscript and giving us valuable comments. We have modified our manuscript according to your comments. We hope that the revised manuscript is now acceptable for publication.

L7 Abstract should be written in a way to attract the international audience.

We have added "Salinity has been a major threat for the sustainability of irrigated agriculture in arid and semi-arid regions." to stress that this paper deals with universal problem rather than local one in Nile Delta.

L34, 39,44 Please add the number of the citation.

We have moved the location of the numbers.

L49 Please add the following references to give a more international flavor in the section of Introduction:

We have referred suggested papers in the first paragraph (L26 in the revised manuscript).

L55 It should be deleted because there is not a subsection 2.2.

We have deleted it.

L62 Please avoid using "We". Apply this correction all over the manuscript.

We have changed the following sentences to passive form:

"Nine observation wells were installed" (L70)

"A value of 130 for CH of the PVC pipe was used" (L100)

L67 The model of instruments for EC measurement and the reagents used for their calibrations should be reported.

We have added those information (L88).

L67 The applied method for the determination of EC should be described in more detail. Please provide the appropriate references.

We have added an equation to calculate pore water conductivity and reference for the 1:2 method (L82).

L75 Please provide reference.

We have added a reference for the equation (L96).

L86 This sentence should be moved to Materials and Methods section.

We have moved the sentence (L75).

L96 Please avoid using "We".

We have changed the sentence to passive form (L117).

L188 the

We have inserted it (L218).

L218 Authors should insert more references to give a more international flavor to the section of Introduction and Discussion.

We have added "Okuda et al. [14] investigated the effect of leaching carried out twice during winter in Uzbekistan and reported that even after 310 mm of leaching and 127 mm of rain, which may be nearly one pore volume down to 80 cm, 75 % of salts remained in top 100 cm. This may also indicate the difficulty of leaching by ponding for fine textured soil." (L144)

Reviewer 2 Report

This paper about the role of bypass-flow in cultivated field is potentially interesting, but in its present form the submission is far to be ready for publication in Water.

The English is very poor: there are a lot of typos and many sentences are obscure and badly constructed. A revision by a mother tongue scientist or a professional proofreading service is warmly recommended prior to resubmission.

The general structure of the paper does not work well, because the logical nexus between two subsequent sentences is often lost.

The methods are not adequately described: very often the authors present data without given any information about method and instruments adopted for retrieving that data.

There is a big disorder in discussion and results, with sudden jumps from an argument to another one.

The scientific content seems interesting and worth of publication, but the issues affecting the present version of the paper are so serious that it is impossible for a reviewer having a correct idea about its overall merit.

Additional comments are reported in the attached pdf file

Comments for author File: Comments.pdf

Author Response

Reply to Reviewer 2

Thank you very much for having reviewed our manuscript and giving us valuable comments. We have modified our manuscript according to your comments. We hope that the revised manuscript is now acceptable for publication.

L7 a primary

We have inserted "the" before primary (L8 in the revised manuscript).

L7 zone, but

We have followed to your instruction(L8).

L8 Repetition, maybe ".. to the removal".

We have changed to "the removal of" (L9).

L8 soils

We have followed to your instruction(L9).

L12 Please add a sentence summarizing the methods used in the study.

We have added "Electrical conductivity of 1:2 extract was measured to evaluate the salinity of soils."(L13).

L13-15 "In addition", "Moreover", "Furthermore". Please connect the sentences avoid repetition of words with a similar meaning

We have replaced those words with "secondly", "thirdly", "fourthly"(L16).

L17 delete

We have deleted those words(L20).

L17 soil, and

We have followed to your instruction(L20).

L29 soils

We have followed to your instruction(L35).

L34 citation different than required: please use the form Minhass et al. [2] here and in all other citations with the same problem

We have followed to your instruction (L39).

L35 Sentence too long without punctuation. Please rephrase.

We have separated it into two sentences by deleting "even though" (L42).

L45 occurred

We think that the present form is more appropriate because it is the statement of general tendency by the Corwin et al., not their experimental results.

L45 cm, although

We have followed to your instruction (L51).

L49 Too long, no punctuation, please rephrase.

We have added punctuation and shortened the sentence (L54).

Table 1 Wrong position: please move the table after its first citation in the text

We have moved it to appropriate position. Actually, in the original manuscript, we placed it in section 2. Maybe editorial assistant moved it to the wrong position.

L56 Please add as Fig.1 a map illustrating where the study area is located.

We have added a map.

L63 Please add details. Depth? Diameter? Casing?

We have added description of diameter and casing (L70). Depth had been presented in the original manuscript.

L67 Please add information about the method for extracting samples? From where? Taken horizontally or vertically?

Since much water far more than enough to saturate the soil in the 1:2 method is applied, water (suspension) in a beaker can easily be sampled to measure EC. To avoid misunderstanding, we have replaced "extracts" with "suspension"(L80).

L69 Please add pictures or schemes illustrating the structure of the experimental field

We have added a map as Fig.2 to illustrate the structure of the field and locations of observations.

L72 Please more information about instruments and measuring methods

We have inserted model information of the water level sensor(L94).

L88 salinity

We are sorry for the typo. We have corrected it(L107).

L89 You should provide a table reporting EC of both irrigation water and soil solutions. From the figure it is exactly the opposite: if for the sample at 0 cm depth you mean the irrigation water, its Ec is about 10 times that one of pore water.

We think that duplicate of data in the text and figure should be avoided. As stated in former text, the electrical conductivity of irrigation water fluctuated between 0.4 to 0.5 dS/m.

L90 Unclear for not expert in the field. Please explain

We have added a sentence to explain the threshold value (L110).

L95 Why speaking of sugarbeet if just before you wrote about rice?

The profile reflects the effect of sugarbeet cropping and the effect of rice had not appeared yet. But to clarify the role of the figure, we have changed the sentence as "Figure 5 shows the profiles of pore water salinity before transplanting of rice (at the end of sugarbeet cropping)"(L118).

L104 labelled

We are sorry for the typo. We have corrected it (L125).

L104 irrigation

We are sorry for the typo. We have corrected it(L126).

L113 This statement is deprived of any data supporting it.

Sentence just after the statement supports it. To facilitate understanding, order of appearance of the two sentences have been swapped(L135).

L114 In which sense "stored" and how did you obtain these values?

Explanation of how we calculated the stored amounts have been added(L134).

L117 What about this value? How did you obtain it?

Reference to the value has been added(L141).

L119 The meaning of this sentence, logically detached from the context, is obscure.

This sentence explains the how large swelling and shrinking occur for the soil. We have added "for the soil"(L144).

L122 How was this measured? No information in the method.

We have added "Groundwater level was measured using a water level meter (Yamayo, WL10M)." in the material and methods section(L73).

L131 X axis label is wrong: it is a time axis

We have deleted the duplicate caption of the figure.

L135 Do you mean the maximum differences between the curves in Fig.5?

Yes, we do. To clarify the statement, we have inserted "between the highest and the lowest levels"(L163).

L172 I definitely disagree: looking at the figures differences as large as the 80% are evident.

Difference in EC of groundwater is far smaller than that between EC of ground water and pore water. We have replaced "quite" with "fairly"(L171).

Figure 8 What's this? No irrigation nor rain

We have no explanation on the temporal discharge. No irrigation nor rain were recorded.

Figure 8 Why the opposite behaviour? This is an increment after rain.

As stated in the original manuscript, "zero value occurred when water level inside the lateral pipe was lower than the electrode of the sensor." To avoid the misunderstanding, "zero value" has been changed to "zero EC values" (L185).

Figure 9 This figure does not add anything more than what presented in the text. It can be eliminated.

We think that it may help to understand the assumption of direct reach of irrigated water to drain.

L171 through cracks

We have followed to your instruction (L199).

L172 maybe salinity

"Salinity" usually is referred as EC and EC appears Eq (5). Therefore, it should be concentration.

L173 qs, not qd

We are sorry for the typo. We have corrected it(L202).

Round 2

Reviewer 1 Report

The paper is improved in relation to its initial version.

There are some minor points that require corrections. Please see the annotated pdf file.

After these small amendements the paper has reached the level of acceptance for publication in the journal.

Regards,

Comments for author File: Comments.pdf

Author Response

Reply to Reviewer 1

Thank you very much for having reviewed our manuscript and giving us valuable comments again. We have modified our manuscript according to your comments. We hope that the revised manuscript is now acceptable for publication.

L59 Figure 1 Please apply this type of correction all over the manuscript.

We have corrected “Fig.” to “Figure.” at two locations (L59, 73)

L65 Study area.

We have corrected as you instructed. (L65)

L68 Please move the caption in a line before the table

It was before the table in the MS-word version. I hope the editorial assistant will address this problem.

L55 Please check the position of the figure because it interrupts text..

We have shifted the figure by two lines. (L77)

L248 2015

We have corrected it (L250)

Reviewer 2 Report

Dear Authors,

after reading the revised version of your manuscript my opinion is that there are some issues to solve prior to publication.

First, the English remains not adequate for an international scientific journal, and I invite you to accurately revise the manuscript, improving its intelligibility, since the effective meaning of many phrases is still obscure.

The main scientific issue is the confusion between electric conductivity (EC) and salinity. EC is a proxy of salinity, but salinity is the concentration of total salts in a solution and has a completely different dimensional consistency: EC is expressed in dS m-1 (as you correctly wrote in your paper) but salinity is usually expressed in mg L-1. You can convert EC to salinity, but you must indicate which formula are you using for the conversion and properly indicate in the graph what is the plotted parameter, salinity or EC, which definitely are different parameters. 

Author Response

Reply to Reviewer 2

Thank you very much for having reviewed our manuscript and giving us valuable comments again. We have modified our manuscript according to your comments. We hope that the revised manuscript is now acceptable for publication.

Comments:

First, the English remains not adequate for an international scientific journal, and I invite you to accurately revise the manuscript, improving its intelligibility, since the effective meaning of many phrases is still obscure.

Response:

We have made following corrections:

monitor groundwater → monitor the groundwater (L70)

Changes in groundwater depth → Changes in the groundwater depth (L159)

about → approximately (L69)

tile drain → the tile drain (L12, 18, 189, 231)

We would appreciate it if you could point out which phrases you think obscure.

Comments:

The main scientific issue is the confusion between electric conductivity (EC) and salinity. EC is a proxy of salinity, but salinity is the concentration of total salts in a solution and has a completely different dimensional consistency: EC is expressed in dS m-1 (as you correctly wrote in your paper) but salinity is usually expressed in mg L-1. You can convert EC to salinity, but you must indicate which formula are you using for the conversion and properly indicate in the graph what is the plotted parameter, salinity or EC, which definitely are different parameters. .

Response:

We have added a sentence to explain how we converted. In addition, we have replaced some of “salinity” with “EC”. (L70, 80, 106, 107,117, 126, 149, 176, 177, 182, 185, 227, 230)