Evaluating the Impact of Nano-Silica and Silica Hydrogel Amendments on Soil Water Retention and Crop Yield in Rice and Clover Under Variable Irrigation Conditions

Round 1

Reviewer 1 Report (Previous Reviewer 3)

Comments and Suggestions for Authors

Suitable in present form

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

Comments and Suggestions for Authors

 

The article addresses the important issue of reducing water use in rice and clover yields with limited water resources. The study was designed correctly nevertheless several questions and comments arise:

1) State the test procedures (test methodology) WRC and hydraulic conductivity (saturated or unsaturated) ? (lines: 186 and 189)

2) To be more specific the test results are too general, please correct based on the results obtained

3) Line: 229 Figure 1 ? should be Figure 2

4) Table 3 bulk densiy (BD g/cm) should be (BD g/cm3)

5) Please insert the measurement units on the vertical and horizontal axes in Figures 2, 3 and 4, this will make the data easier to read.

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report (New Reviewer)

Comments and Suggestions for Authors

This article explores a fascinating approach to improving water use in agriculture by using silica. The urgent need for sustainable solutions and specially regarding water use, should be more visible in the paper.

I have some suggestions that might help strengthen the paper. My comments want to be constructive and contribute to the overall clarity and impact of this research.

1. In general, the introduction sets the stage by highlighting the growing problem of water scarcity in agriculture and its impact on crop production. It correctly emphasizes the importance of finding sustainable solutions to improve water use efficiency.
2. However, some sentences could be restructured for better clarity and flow. For example, lines 44-46, the sentence "The challenge is further compounded by climate change, which is expected to make irrigated agriculture more difficult. By 2025, it is estimated that one in four people will face severe water shortages [4], heightening the urgency for more sustainable agricultural practices." could be broken down into two shorter and concise sentences.
3. While the introduction mentions the benefits of hydrogels and silica gel, it would be helpful to be more specific about how these materials improve soil properties.
4. The introduction's ending feels a bit abrupt. The objective, "to fill that gap by exploring the effectiveness of both silica 86 and nano-silica hydrogels as soil amendments to improve water retention," could be stated more precisely. Consider rephrasing to create a clearer sense of direction for the reader.
5. The Materials and Methods section provides a solid overview of the experimental setup, materials, and analytical methods. The experimental design appears sound. However, Figure 1 could benefit from greater clarity and more descriptive labeling.
6. I'm a bit puzzled by the absence of a traditional control group (100% full irrigation without any hydrogel). The statement "100% full irrigation used as the control" is a little confusing. Could you clarify this? Also, the rationale behind the 10cm application depth should be explained.
7. The reasoning behind the chosen hydrogel application rates needs further explanation. Were these rates based on existing research, established recommendations, or preliminary experiments? Providing this context would be very helpful.
8. Please provide more detail about the soil sampling procedure. Were samples taken randomly within each plot? How were they homogenized? And how were they stored before analysis? This information is crucial for reproducibility.
9. Please specify the software used for your statistical analyses.
10. The results, while generally well-presented, raise a few points. Table 2 is well-organized, but the high "C.V." values for some parameters, particularly in 2023, suggest substantial variability within the treatments. Please address and discuss this variability. Please consistently clarify what the asterisks in the "P values" column represent (e.g., *p < 0.05, **p < 0.01, ***p < 0.001).
11. Throughout the results section, be sure to consistently report the statistical significance of your findings. Instead of simply stating "significantly improved," please provide the associated p-value whenever possible.
12. The discussion often repeats information from the results section. Focus on interpreting the results, comparing them to previous research, and discussing the implications of your findings
13. Moreover, the conclusions mention the need for further research on long-term effects. This point should also be addressed in the discussion section. What are the potential long-term benefits and risks associated with using nano-silica hydrogels? Discussing these possibilities would add depth to the paper.
14. The mention of "char materials" in the conclusions is unexpected, as it wasn't discussed in the results or discussion sections. Either remove this mention or incorporate a brief discussion of char materials in the relevant sections.
15. Finally, a minor point: Please carefully proofread the text for grammar and typos. For example, on line 44, the phrase "By 2025, it is estimated..." could be slightly rephrased for smoother flow. A proofread before submission is always a good task to do.

Comments on the Quality of English Language

Some minor details, nothing relevant.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report (New Reviewer)

Comments and Suggestions for Authors

Thanks for improving the article and considering the comments given.

I think that your paper will have interest for researchers.

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

Comments and Suggestions for Authors

The aim of the study is of significant importance. However, the design, execution, and outcomes of the experiment have not been adequately addressed or presented.

 

Title

The title of the manuscript does not make sense. It’s water retention of soil instead of these plants, right? Please revise it to make the key message clear.

 

Abstract

What do you mean by “water productivity” in line 19? I don’t think the strategy is “producing” water.

Line 24, what is the specific measurement/parameter of water requirement? Be specific.

Please provide more statistically significant comparison for the outperformance of the amendments rather than simply describe it.

 

Keywords

No more than 6 keywords.

 

Introduction

The paragraphs are too short. Some of them conveying the same main idea can be combined.

 

Materials and Methods

Section 2.1.1–2 can be combined.

Section 2.1.4.1–2 can be emerged and more details should be provided.

Section 2.2-2.3 should be combined and the subheading should be revised.

Remove the bullets in this section and use a more professional style to summarize the experiment. Details should be provided for others to repeat the same experiment. For example, how did you apply the amendment with soil? How deep?

There is a lack of control block that contains neither silica hydrogel nor nano-silica hydrogel. Why?

How did you collect the samples? How many samples did you collect?

The description of statistical analysis is vague. BTW, there is typo “Statical” in line 149, which should be “statistical”.

The results and discussion section are too shallow without in-depth explanation.

 

Conclusions section should provide more implicative information.

 

References are not up to date enough, especially 15, 27, 29, 30, 31, 32, 33, 37

 

 

Comments on the Quality of English Language

The language must be improved.

Reviewer 2 Report

Comments and Suggestions for Authors

The study titled “Evaluation of Nano Silica and Silica Hydrogel Amendments on Enhancing Water Retention and Crop Yield of Rice and Clover under Variable Irrigation” seems interesting and relevant to the water-limiting agroecosystem. However, the manuscript needs to be improved.

General comment

It is advised to add the following in the introduction.

How long do the hydrogels last in the soil? Does this yearly application or one-time application provide many years of benefits? What are the current uses of hydrogels in agricultural land? Are there any concerns about using different types of hydrogels in the agroecosystem?

Specific comments

Line 63: what are the practices of hydrogel application rates in agriculture?

Lines 93-100, methods for characterizing soils and water retention properties with references.

Lines 103-107, is there any specific reasons for selecting these crops?

Lines 110-112, is this hydrogel available commercially in the market?

Lines 127-128, what are the rationales for choosing these application rates?

Lines 130-132, 60%, 70%, 80%, and 90% of recommended water applied, compared to full irrigation as the control. How was the irrigation limited?

Table 1: how were the Characteristics of Silica Hydrogel and Nano-silica Hydrogel confirmed?

Lines 133-136 elaborate on the process.

Line 225, 3.4.the analyze the PCA biplot. Capitalize the T at the beginning.

253-305, discuss your results with reference to the related previous studies, if possible, and provide citations. Another thing to discuss further in future research is that hydrogels can be combined with char materials that are not decomposable in the soil to provide long-term soil benefits. Manure mixed with char materials provided significant benefits to soil and crop yield. (see the most recent study: https://www.mdpi.com/2571-8789/8/3/82). 

 

 

 

Reviewer 3 Report

Comments and Suggestions for Authors

Problems with water shortages and their impact on agriculture and crop yields are a very important issue that is important for all people around the world. Any solutions that are intended to solve this problem are very interesting and worthy of attention.

However, this article requires a few corrections.

1. The authors conducted research for rice and clover. However, the introduction lacks a justification for why clover was chosen for research. This should be supplemented.

2. The authors proved that the hydrogels used had a beneficial effect on crop yield. However, was it checked whether the presence of nano-silica hydrogels does not cause, for example, the accumulation of nanosilica in the tested plants? The effect of some substances cannot always be observed in the appearance and yield of plants. The accumulation of silica in plants can affect crop quality.

3. The authors studied the effect of hydrogels on the water retention properties in the soil. However, were other soil quality parameters checked. Water retention in the soil is very important, but how does the addition of hydrogels affect soil quality in general?

4. The discussion should be improved and supplemented. There are chapters in which the authors only analyze the obtained results and do not refer them to literature data.

5. I suggest the authors re-read the manuscript carefully to remove any minor linguistic or punctuation errors.