Vertical Distributions of Soil Nutrients and Their Stoichiometric Ratios as Affected by Long Term Grazing and Enclosing in a Semi-Arid Grassland of Inner Mongolia

Round 1

Reviewer 1 Report

I have minor comments. Please find it in the attached pdf.

Comments for author File: Comments.pdf

Author Response

Response for Reviews

Dear editors and reviewers:

Thank you for your letter and for the reviewers’ comments about our paper. Those comments are all valuable and helpful for the improving of our paper. We have carefully discussed and studied the comments and have seriously revised in red in the paper. I'm sorry to reply so late. We have revised the paper for several days.

Response to reviewers' comments:

1. The results showed that long term grazing decreased the dry matter of green plant and litter (P<0.01), and it associated with lower silt (2-50 μm) (5.9%) and higher fine sand (100-250 μm) (6.0%) in 0-10 cm soil. Long term grazing slightly increased bulk density and significantly increased electrical conductivity in each soil layer (0-100 cm). These sentences had been highlighted by reviewer.

Response: We are very sorry. This paper not included dry matter of green plant and litter, however these contents were observed in abstract, so we had deleted “The results showed that long term grazing decreased the dry matter of green plant and litter (P<0.01)”. The relatively results of soil physical property had been deleted in this paper, so we also deleted “and it associated with lower silt (2-50 μm) (5.9%) and higher fine sand (100-250 μm) (6.0%) in 0-10 cm soil. Long term grazing slightly increased bulk density and significantly increased electrical conductivity in each soil layer (0-100 cm)”.

2. Line 31, Grazing and enclosing are two of the most important grassland managements, which can directly or indirectly take effect on the balance of ecosystem.

Response: We have deleted “take” and “on”.

3. Line 88-90. Up to the year of sampling, the enclosing plot was grazing excluded 38 years (since 1981), which has long term exclusion of livestock and the vegetation and soil have been recovered well. These sentences had been highlighted by reviewer.

Response: We have revised as “Up to the year (2018) of sampling”.

4. Line 333. Dickinson et al. (1981) reported that nutrients elementsuch as P, Ca, and Mg feed by cattle was excreted into grassland.

Response: We have deleted “element”.

5. Line 352-353. and the input of organic matter to deep soil was reduction with the increasing of soil depth.

Response: We have revised as “and the input of organic matter to deep soil reduction with the soil depth”.

6. In conclusion.

Response: We have deleted “These might indicate that long term grazing increased the most of nutrient contents and improved the mineralization of soil organic matter in surface soil especially, and thus might promote the nutrient cycling in grassland ecosystem, whereas long term enclosing might limite the nutrients cycling in a semi-arid grassland of Inner Mongolia”.

Author Response File: Author Response.docx

Reviewer 2 Report

General comments

The research focuses on changes in soil nutrients, physical properties and stoichiometric ratios of nutrients at different vertical depths in grazing and enclosing grasslands of Inner Mongolia. The article is within the scope of Agriculture and is of interest. The article needs thorough improvement in the introduction, description of methods and include implications of this studies to pastures/plant growth for grazing. Also, there are some grammatical errors that need to be fixed throughout the manuscript. Here below are specific comments.

Title

The title of this article should be modified because it does not clearly describe the objectives of the research. The current tittle “Soil Physical Property and Nutrients as Affected by Long Term Grazing and Enclosing in a Semi-arid Grassland of Inner Mongolia”, does not mention soil stoichiometric ratios and vertical patterns or soil layers. I think adding this will improve it. Moreover, the soil physical property exists in the title but not in the objectives. The title should match with the objectives. Introduction The introduction provides extensive review on soil nutrients and stoichiometric ratios significant to this study. However, there is lack of background on the effects of grazing on soil physical properties. The tittle therefore is not suitable for the study without soil physical property background. It is important to add information about the soil physical damages due to grazing and enclosing. Moreover, the objectives does not mention soil physical property. In the present format, the tittle is not suitable. Either the tittle could be changed to focus on vertical variation in soil mineral nutrients and their stoichiometric ratios in the grazing land or the soil physical properties information added to enrich the background. The introduction should also make available information about how imbalances in soil nutrients as a result of changes in ratio affect plant growth and clearly be related to biomass production of pastures. A reference should be added to the first sentence of the opening paragraph in the introduction. In Line 31-32, “At present…….very different”, please add references of these studies. In Line 66, “related to the various”, the word various makes the meaning unclear to readers. Please modify the sentence. In Line 63, “while these mineral nutrients and available nutrients were largely ignored in recent researches.”,I do not think it is suitable here.

Methodology

Please specify how large were the fields for study/sampling, in terms of acres or hectares. Please rewrite the model, company, city and country of the atomic absorption machine in the bracket, e.g. (Model AA240, Varion, Palo Alto, CA). Please add the method used to determine soil texture and describe in detail. State why the sampling was performed at different depths instead of the top soil (0-15 cm). Furthermore, describe how soil pH was measured. What was ratio of soil to solution (was it water or calcium chloride?). In the case of water, some researchers use 1:5 ratio i.e. one gram of soil mixed in 5 mL of water. Show the instrument used to measure the soil pH and EC. Add the units for soil EC on the graph. In addition, describe into details how soil bulk density was measured. Include sampling using cores in the fields if performed. Please state the model of the UV spectrophotometer machine, inclining the wavelength of analysis, e.g at 210 nm? Please rewrite statistical package used to analyze data as SPSS software version 10.0 (SPSS for windows Inc., Chicago, Illinois, USA).

Results

I recommend increasing sizes of figures for clear visibility. Was soil texture analysis conducted at all the soil depths? Please specify. Add the units of soil EC and state whether pH is H2O or CalCl2 including ratio of solutions. Add the EC unit.

Discussion

In Line 285, “This results were consistent with many studies”, please add the studies to which reference is being made. In Line 302, I think leaching of nutrients occur and when salts accumulate, the EC value is increased. Please modify the statement “leaching for smaller biomass and litter of long term grazing”. In Line 317, “This were consistent”, replace “were” with “was”. The discussion section was clearly presented. However, there is inadequate information on the implications in changes in soil physical and chemical properties for quantity/yield of dry matter of green plants and litter. The changes in soil nutrients and ratios should be discussed while relating to growth of pastures. For instance, if soil N becomes limiting, what happens to the quantity of pastures harvested? Reference and reference List Please format the references in accordance with the style of Agriculture Journal. The current manuscript reference style is not that commonly used by Agriculture Journal. Do the same for the reference list.

Also check for errors in referencing. Example is

53. Zhao, F.Z., Kang, D., Han, X.H., Yang, G.H., Feng, Y.Z., Ren, G.X., 2015. Soil stoichiometry and carbon

storage

54. in long-term afforestation soil affected by understory vegetation diversity. Ecol. Eng. 74, 415–422. https://doi.org/10.1016/j.ecoleng.2014.11.010.

Thank you.

 Author Response

Response for Reviews

Dear editors and reviewers:

Thank you for your letter and for the reviewers’ comments about our paper. Those comments are all valuable and helpful for the improving of our paper. We have carefully discussed and studied the comments and have seriously revised in red in the paper. I'm sorry to reply so late. We have revised the paper for several days.

Response to reviewers' comments:

1. The results showed that long term grazing decreased the dry matter of green plant and litter (P<0.01), and it associated with lower silt (2-50 μm) (5.9%) and higher fine sand (100-250 μm) (6.0%) in 0-10 cm soil. Long term grazing slightly increased bulk density and significantly increased electrical conductivity in each soil layer (0-100 cm). These sentences had been highlighted by reviewer.

Response: We are very sorry. This paper not included dry matter of green plant and litter, however these contents were observed in abstract, so we had deleted “The results showed that long term grazing decreased the dry matter of green plant and litter (P<0.01)”. The relatively results of soil physical property had been deleted in this paper, so we also deleted “and it associated with lower silt (2-50 μm) (5.9%) and higher fine sand (100-250 μm) (6.0%) in 0-10 cm soil. Long term grazing slightly increased bulk density and significantly increased electrical conductivity in each soil layer (0-100 cm)”.

2. Line 31, Grazing and enclosing are two of the most important grassland managements, which can directly or indirectly take effect on the balance of ecosystem.

Response: We have deleted “take” and “on”.

3. Line 88-90. Up to the year of sampling, the enclosing plot was grazing excluded 38 years (since 1981), which has long term exclusion of livestock and the vegetation and soil have been recovered well. These sentences had been highlighted by reviewer.

Response: We have revised as “Up to the year (2018) of sampling”.

4. Line 333. Dickinson et al. (1981) reported that nutrients elementsuch as P, Ca, and Mg feed by cattle was excreted into grassland.

Response: We have deleted “element”.

5. Line 352-353. and the input of organic matter to deep soil was reduction with the increasing of soil depth.

Response: We have revised as “and the input of organic matter to deep soil reduction with the soil depth”.

6. In conclusion.

Response: We have deleted “These might indicate that long term grazing increased the most of nutrient contents and improved the mineralization of soil organic matter in surface soil especially, and thus might promote the nutrient cycling in grassland ecosystem, whereas long term enclosing might limite the nutrients cycling in a semi-arid grassland of Inner Mongolia”.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Dear authors,

The manuscript has greatly improved. All my concerns have been addressed. However, in line 27-30, rearrange the references in the brackets to begin with the oldest to newest. E.g (Mekuria et al., 2007; Liu et al., 2017). Do the same to the other citations in the manuscript for consistency. 

 I have no additional comments.

Thank you.