Spatiotemporal Variation of Soil Enzyme Activities and Their Dominant Drivers in Salinized Wheat Fields of the Yellow River Delta

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript analyzed the characteristics of soil water-salt transport, nutrient distribution, and key carbon-metabolizing enzyme activities in salinized wheat fields of the Yellow River Delta under different salinity levels, and explored the correlations among these factors. The dataset is relatively large, and the methodology is generally reasonable. However, there are several issues and suggestions for the authors to consider:

1.The introduction section mainly reviews the background of saline soils, enzyme activities, and nutrient cycling. It is recommended to add a paragraph that clearly states the scientific questions to be addressed and the basic hypotheses of this study.

2.Only low, moderate, and high salinity treatments were set up, without a non-salinized control group. The authors should explain the reason for this design.

3.There are obvious errors in some figures (e.g., Figure 5, where the title refers to "AK" but the content appears to describe "SOM"). Careful proofreading is needed to ensure consistency and accuracy.

4.Although ANOVA was used, the authors did not specify whether post-hoc tests (e.g., Tukey HSD) were conducted, nor did they provide specific P-values (only * symbols were used to indicate significance). It is recommended to include detailed statistical results.

5.Under high salinity conditions, electrical conductivity (EC) showed a significant positive correlation with the activities of S-SC, S-AL, and S-CL, which is inconsistent with previous studies reporting salt-induced inhibition of enzyme activity. The authors are advised to compare these findings with the literature and provide possible explanations for the observed differences.

6.The discussion section is somewhat superficial, with too many management suggestions and insufficient mechanistic analysis. It is recommended to include more in-depth discussion supported by relevant literature or potential mechanisms.

7.The reference list is not formatted consistently. Please revise the references according to the journal’s formatting requirements.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

It is known that enzymatic activity is a reliable indicator of soil properties. The soil enzyme pool is formed as a result of the long-term evolution of soils, is able to remain in the soil for a long time and show its activity. The key enzymes of soils are a group of enzymes (cellulase, sucrase, amylase) that ensure the breakdown of carbon-containing compounds at different stages, determining the rate and direction of the soil carbon cycle. This important feature of enzymes ultimately determines the fertility of soils, and therefore the productive capacity of stands and crops. However, under conditions of anthropogenic impact, soil properties are disrupted, and therefore conditions for the work of enzymes. The high content of enzymes in the soil does not ensure their operation, and therefore, a violation of the turnover rate of substrates in the soil occurs. One of the negative manifestations of anthropogenic impact on soils is their salinization. Changes in acid-base parameters, ionic composition of soils and other undesirable changes lead to a sharp disruption of the conditions in which the enzyme pool is formed, the composition and activity of enzymes are disrupted. Currently, despite the fact that there are enough works devoted to the study of the enzymatic activity of soils, there are no works of a certain local level: the Yellow River Delta. In this regard, the proposed article in the field of studying soil salinity at specific research sites is very timely and relevant.  Overall, the work makes a very good impression, it is easy to read, and all the terms are used correctly. The latter, as is well known, determines the accessibility of the article to foreign colleagues who would like to familiarize themselves with this work. The paper considers the results of the model experience. As you know, it is quite difficult to perform model experiments under controlled conditions, since a good methodological basis for doing the work is needed. The authors of the article coped with this task, there are no comments on the organization of the experience. Methods for determining chemical parameters and enzymatic activity correspond to the objectives of the work and the task. A general note to the article is the complete absence of primary, tabular materials. It seemed that the authors decided to disguise (hide, in other words) all the data obtained (even the basic ones), "remove" them into the drawings. And it is very difficult to understand the drawings, since they are very small, the color scheme is in the style of a "frightened nymph" (very pale pink, green and blue, yellow). However, this small remark does not negate the overall good impression of the time-consuming and very difficult work done by the authors. The comments to the article are given below. I wish the authors good, friendly work, and financial success!

2-4- the title in a bunch, enzymes, correlation analysis, and the place of work.

Maybe just write…

 The effect of salinity on the enzymatic activity of soils formed under wheat in a model field experiment (using the example of the Yellow River Delta)..We need to think about it, but it shouldn't be

16-37- we need to redo everything!

Relevance

Goals

Where the work was completed

Experiment. Clearly. Decipher the entire abbreviation!!!

Results (show the numbers, otherwise everything is "closed" again!). Write a phrase, for example, "According to the enzymatic activity of the soil, it is possible to arrange in a row in descending order: weak salinity > medium salinity > strong salinity)"

Conclusions

Practical significance.

Everything is clear, without "spreading porridge on a plate.

38 -words should not repeat the title of article

41- is there really no such problem as salting in the world anymore! Is it really only in China that this problem exists? I read the magazine in different countries, so I need an overview of the world's articles.

79- what does biochar have to do with it

74- would you like a more detailed, in-depth explanation of why you chose these hydrolytic enzymes? Do they have similarities in structure and are there any differences, which metal is part of the active center of the enzyme, etc

95- only in China?

102-105- separate your thoughts, not very clearly

123-are there any photos, it is necessary to document, since you did a model experiment, to confirm the work done (especially since the magazine allows you to do this)

132 -why are there no references to literature

177-178- make methods for the determination of enzymes separately. These are the objects of your research!Did you have a control that was heated at a temperature of 105 degrees? So did you identify extracellular enzymes?

220 - is very small, it is difficult to read the picture

Temporal and spatial variation characteristics of EC wheat field soils. (a) low-salinity; (b) moderate-salinity; (c) high-salinity.

275-what do the vertical columns show?

296- the legend in the drawings is not very clear, remove the double lines

300-sign all the drawings, make them the same

308-309, 321 – this is for discussion...then check again

397- I didn't see the legend

410-everything is clear, understandable, very interesting, but not clear, the colors are not bright

416-good numbers, interesting

480-487 is a very important part of the work, but there is one link. You haven't studied halophilic bacteria, have you? And how does the Na-K pump change in plant cells? It's hard to believe that it's only thanks to microorganisms that the activity of enzymes changes, and the remains of plants? This is a question for reflection.

Once again, I would like to note the tremendous work that has been done. I wish you continued prosperity!

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Everything is written well, the terms are used correctly

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Accept in present form

Reviewer 2 Report

Comments and Suggestions for Authors

Dear colleagues! Thank you so much for changing the article based on my recommendations, it became more interesting and correctly designed. Thank you. Everything is very good. Well done