Effects of Warming and Precipitation on Soil CO₂ Flux and Its Stable Carbon Isotope Composition in the Temperate Desert Steppe

Round 1

Reviewer 1 Report

These authors have improved upon a previous manuscript, and it is now in good shape. I found no real problems and I think that a careful proofreading to catch the small errors of English is all that is needed at this stage.

Author Response

To Reviewer 1

We thank the reviewer for reading our paper carefully and giving the above positive comments. We will carefully proofread any questions about English details.

Reviewer 2 Report

Both warming and increased precipitation are important climate change. They have and will continue to affect terrestrial ecosystem globally. This study examined the effects of two magnitudes of warming and increased precipitation on soil respiration. It is an interesting study. However, before it can be accepted, there are several issues which may be can improved.

1. Since there are two magnitudes of warming and increased precipitation, the authors can consider to examine whether or not the effects of warming or increased precipitation on soil respiration are nonlinear. Actually, several studies have found that soil respiration had nonlinear  responses to warming and increased precipitation (e.g., Yu et al., 2019, Science of the Total Environment; Shen et al., 2016, Polish Journal of Ecology; Shen et al., 2015, Applied Soil Ecology). However, this study did not make this.
2. Since this study measured two years of soil respiration, the authors can consider to compare inter-annual variation of soil respiration and warming or increased precipitation effects on soil respiration. Actually, several studies have found that the effects of warming and increased precipitation on soil respiration were lower than inter-annual variation of soil respiration (e.g., Yu et al., 2019, Science of the Total Environment; Fu et al., 2019,  Science of the Total Environment).

 

References

Fu et al. Asymmetrical warming of growing/non-growing season increases soil respiration during growing season in an alpine meadow.  Science of the Total Environment, 2022, 812, doi: 10.1016/j.scitotenv.2021.152591.

Yu Chengqun, et al. Effects of experimental warming and increased precipitation on soil respiration in an alpine meadow in the Northern Tibetan Plateau. Science of the Total Environment, 2019, 647: 1490-1497.

Shen Zhenxi, et al. The soil drying along the increase of warming mask the relation between temperature and soil respiration in an alpine meadow of Northern Tibet. Polish Journal of Ecology, 2016, 64(1): 125–129.

Shen Zhenxi, et al. Response of soil respiration to short-term experimental warming and precipitation pulses over the growing season in an alpine meadow on the Northern Tibet. Applied Soil Ecology, 2015, 90: 35-40. 

Author Response

Dear reviewer 2：

    Please see the attachment

Best regards.

Na Guo

Author Response File: Author Response.pdf

Reviewer 3 Report

Review on manuscript: sustainability-1624186-Effect of Warming and Precipitation on Soil CO2 Flux and its Stable Carbon Isotope Composition in the Temperate Desert Steppe

 

This manuscript is an interesting study, which provided the crucial knowledge for the readers. However, there are some points that must be improved before publication.

 

Line 40: “soil organic carbon” may be “SOC”.

Line 41: “Desert Steppe” should be one of the keywords.

Lines 45-46: “As a vital carbon (C) pool, soil is sensitive to climate change.” The references are needed. I recommend these papers:

 Arunrat, N., Sereenonchai, S., Wang, C. 2021. Carbon footprint and predicting the impact of climate change on carbon sequestration ecosystem services of organic rice farming and conventional rice farming: A case study in Phichit province, Thailand.  Journal of Environmental Management, 289, 112458. doi:10.1016/j.jenvman.2021.112458

Arunrat, N., Pumijumnong, N., Hatano, R. 2018. Predicting local-scale impact of climate change on rice yield and soil organic carbon sequestration: A case study in Roi Et Province, Northeast Thailand. Agricultural Systems, 164: 58–70. doi.org/10.1016/j.agsy.2018.04.001

Line 68: “SOC” must be mentioned as “soil organic carbon” at the first place.

Lines 79-101: The objectives of this study are not clearly mentioned. It presented only the hypothesis. Moreover, the contribution of this study to the scientific knowledge should be mentioned.

 Line 115: “soil  organic  carbon  content  (SOC)” should be “SOC”.

Lines 122-125: It would be clearer if you provide the scientific reasons why temperature levels of +2 and 4 °C and precipitation levels of +25% and 50% were adopted in the experiment. Why not consider the negative level as well; e.g -2 and -4 °C or -25% and -50%?

Lines 172-173. “soil  organic  carbon  content  (SOC)” should be “SOC”.

Lines 196-204; Which software was used for statistical analyses?

Lines 323-324: “the positive relationship between ST and SOC content has been confirmed.” Please explain the reasons. In many cases, increasing of soil temperature lead to decline in SOC due to increasing of microbial activities, resulting in increased soil respiration as CO2.

Lines 326-327: “the increase of soil CO2  flux caused by warming may be attributed to the increase of soil C content caused by warming.” How soil C content increased due to warming?

Lines 424: “The thesis…” should be used “The study…”

Lines 431-432: “…the increased soil CO2 flux under warming treatment was caused by the enhanced of SOC content…” It seems unclear explanation in the results and discussion parts.

Lines 439-440: You did not measure, report the results and discuss about “organic matter”. How can you conclude about it?

Author Response

Dear reviewer 3：

    Please see the attachment

Best regards.

Na Guo

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

I think it can be accepted.

Reviewer 3 Report

I have no further comments.