Impact of Long-Term Nutrient Supply Options on Soil Aggregate Stability after Nineteen Years of Rice–Wheat Cropping System

Explanation to Reviewer #1:

A report for: land-1837128. The described study is of international relevance, because fully cover all important tasks of the topic.

The article is well written for the most part and should be of interest to readers.

The result and discussion was in-depth. Statistical tools were used. Therefore, can be considered for publication after slight revision

Thank you so much for appreciating, valuable comments and suggestion

Part of the introduction section is not relevant to the research objectives. I suggest reduce, or delete some parts.

Agreed, revised as suggested

Results and discussion are very well written. This is very important because it will be the basis to contrast with other areas that have the same type of soil.

Agreed, thank you so much for your valuable feedback.

Line 40. Soil aggregate stability improve soil quality, porosity, nutrient and water store capacity, food production and decrease soil and nutrient loss. I am not sure if this sentence is correct.

Modified

Please improved the quality of figure 1 and 2.

Agreed, added revised figures

The number of decimal places in tables should be reduced, i.e. I suggest to put the texture values with a single decimal.

Agreed, and modified

The article should be enriched with some information about the geology and soil types

Agreed, added in M & M section

I suggest to include some experimental photos.

Agreed, and added

I wish those changes will contribute to improve your paper.

Thank you so much for your valuable suggestion and comments for improvement.

Explanation to Reviewer #2:

Please consider addressing some major and minor issues related to the current study:

Thank you so much for your valuable comments and suggestion

Please consider further describing the climatic conditions in the area of interest. For example, consider adding a Table with the minimum, maximum, average, standard deviation, skewness, and kurtosis of monthly temperatures and precipitation.

Added as Table No 2

2) Please add more information on the soil moisture conditions, since it is considered to play a significant role in your study. Also, consider adding other studies in the literature (if found related) that deal with soil moisture and its impact on soil stability and shear strength (e.g., Gerard, 1965; Gong et al., 2022).

Agreed, we have added information in revised MS. Both references are excluded.

3) One of the main limitations of the ANOVA test is the lack of long-term correlation (or else called Hurst phenomenon or long-range dependence), which is shown to increase the variability and uncertainty of the process (here, the examined process is the soil stability). It is found that many hydrological processes related to the water-cycle exhibit such long-range dependence (LRD), such as soil moisture (see Deng et al., 2020; Rodriguez-Iturbe et al., 2020), precipitation or temperature (see Dimitriadis et al., 2021). I suggest to add the LRD as another factor that may highly affect the soil aggregated stability in the long-term (such as the current one by the authors).

The produced data was treated for analysis of variance (ANOVA) and Duncan’s multiple range test (DMRT) p < 0.05 was performed to test statistical differences in soil aggregation fractions (i) > 2,000 μm; (ii) 250–2,000 μm; (iii) 53–250 μm; (iv) and < 53 μm, macroaggregate, microaggregate and means weight diameter between different treatment combination and soil depth. To check the data normality, Shapiro–Wilks test was per-formed. The relationship among macroaggregate, microaggregate and means weight diameter of both soil layer were described by linear regression functions.

Experimental was established in Randomized Block Design (RBD) with four replications.

4) Please consider expanding the literature review on the impact of rice cropping on clay and silt soils (e.g., if it is found related, see So and Ringrose-Voase, 2000).

Thank you so much for excellent article, we included in discussion section.

5) In section 2.3, it would be useful for the readers to add a sample photo of one of the soil samples. Also, is it possible to justify whether the number of samples is sufficient for the statistical analysis?

Agreed, experimental photographs added and yes number of samples are sufficient for statical analysis (treatments 7 with 4 replications under RBD)

6) Is it possible to justify the Equations used in Figures 6-8? For example, is there any physical justification for the linear relationship between "Mean weight diameter" and "Microaggregates", since it seems that a power-law fit (or another expression) could perform better? I think it is important to try and justify why linear relationships are applied or why a negative/positive correlation is found between them, since without physical (and not only statistical) justification one may argue that if the data change (in quality, in length or in variaty) then the results could also change.

As mentioned, we use linear relationships between different parameters.

MWD was calculated by following-:

First, we tested linear relationship and we found significant R2 values-:

1.       Macroaggregate was significantly negatively correlated with and microaggregate (R2 = 0.99, p < 0.01; Fig. 6a) in 0-15 cm soil depth.

2.       For 15-30 cm soil depth (R2 = 0.98, p < 0.01; Fig. 6b).

3.       Macroaggregates with mean weight diameter results showed positive strong relationship (R2 = 0.93, p < 0.01; Fig. 7a) in 0-15 cm soil depth

4.       For 15-30 cm soil depth (R2 = 0.92, p < 0.01; Fig. 7b). 

5.       Microaggregate and MWD had significantly strong negative relationship (R2 = 0.89, p < 0.01; Fig. 8a) in 0-15 cm soil depth

6.       For 15-30 cm soil depth (R2 = 0.86, p < 0.01; Fig. 8b). 

7) Please give more details on the applied long-term experiment, since it is not very clear from the text (for example, the soil samples were taken at present and before 19 years? What are the results and statistical significance of the ANOVA test? Is it possible to combine all variables in a unique equation?, etc.).

Agreed, details of experiments have been incorporated in M & M section.

8) Please consider further discussing how the current study justifies its title "Impact of Long-Term Nutrient Supply Options on Soil Aggregate Stability after Nineteen Years of Rice-Wheat Cropping System". For example, were the same impacts on the soil stability observed after 15 or 10 years of rice-wheat cropping? Is it possible to create a Table with the weight impact (in %) of each factor that found to affect the soil stability?

Agreed, in present study first author involved as PhD student and it might be same or different pattern or results after 10 or 15 years of rice-wheat system. In this study we got an opportunity to do study after completing of 19 cropping cycles of cropping system.

9) Strong grammar and syntax changes are required in the whole manuscript. For example, please rephrase the sentences located in the Abstract and Introduction (in the rest of the text, the authors should find and correct any grammar and syntax mistakes):

Agreed, thank you so much for your valuable comments and suggestion. In revised MS we corrected grammatical errors as suggested.

a) "Integrated plant nutrition system (IPNS) and organic farming (OF) options have been contemplated a sustainable strategy to sustain soil aggregate stability under adverse climatic conditions and a possible tool to restored degraded soil system." by either replacing the adjective "sustainable" or the verb "sustain".

Agreed, and modified as suggested

b) "Results showed that significantly, highest (+31%) macroaggregates of the total aggregates and was the dominant in the surface soil layer than subsurface soil." to "Results showed that significantly higher (+31%) macroaggregates were dominant in the surface soil layer than in the subsurface soil.".

Agreed, and modified as suggested

c) "The MWD significantly increased greater (+17%) between surface and subsurface soil." to "The MWD was significantly increased (+17%) between surface and subsurface soil.".

Agreed, and modified as suggested

d) "Overall, results suggested that adoption of IPNS options such organic farming (OF), RDF, STCR and inclusion of pulses (berseem and cowpea) significantly improved all soil aggregation fractions in the soil system, also offers an additional benefit in terms of soil sustainability." to "Overall, results suggested that adoption of IPNS options, such organic farming (OF), RDF, STCR and inclusion of pulses (berseem and cowpea), significantly improved all soil aggregation fractions in the soil system, by also offering an additional benefit in terms of soil sustainability.".

Agreed, and modified as suggested

e) "Soil aggregate stability improve soil quality, porosity, nutrient and water store capacity, food production and decrease soil and nutrient loss." to "Soil aggregate stability improves soil quality, porosity, nutrient and water storage capacity, and food production, as well as decrease soil and nutrient loss."

Agreed, and modified as suggested

f) "Soil aggregates are the fundamental indicator of soil structure, and store plant nutrient, which help to growth and development plant" to "Soil aggregates are the fundamental indicators of soil structure and store plant nutrient, which help growth and development of plants".

Agreed, and modified as suggested

g) "Judicious application of organic manures and inorganic fertilizers accelerates soil aggregation, improve organic matter in agriculture soils" to "Judicious application of organic manures and inorganic fertilizers accelerate soil aggregation, and improve the organic matter in agriculture soils".

Agreed, and modified as suggested

h) "Mismanagement of agriculture practices are major cause of land degradation, four types of land degradation" to "Mismanagement of agriculture practices are one of the major causes of land degradation, analyzed in four types:"

Agreed, and modified as suggested

i) "Minimum soil disturbances, balanced application organic manure and mineral fertilizers, preservation soil covers, and adoption of pules and green manuring crops in cropping system had positive impact on soil aggregate stability, restore degraded land which could lead to superior crop growth development." to "Minimum soil disturbances, balanced application organic manure and mineral fertilizers, preservation soil covers, and adoption of pules and green manuring crops in cropping systems, had positive impacts on soil aggregate stability, by restoring degraded land, which in turn could lead to a superior crop growth development."

Agreed, and modified as suggested

g) "Hence, to implement, design, and adoption of most effective IPNS options to optimize the soil aggregate stability, it is vital to launch efficient regulating, monitoring, and restoring assessment of soil aggregate stability and food security." to "Hence, to implement, design, and adopt most effective IPNS options towards optimizing the soil aggregate stability, it is vital to launch efficient regulating, monitoring, and restoring assessment of soil aggregate stability and food security."

Agreed, and modified as suggested

k) "Moreover, we could not find studies of different nutrient supply options..." to "Moreover, there is a lack of studies in the literature about different nutrient supply options...".

Agreed, and modified as suggested

Explanation to Reviewer #2:

Comment 1# Please consider adding more information in Table 2 (such as standard deviation, skewness, and kurtosis), as requested from the previous review.

Reply # Agreed and modified as suggested. Now in Table 2 we have added standard deviation, skewness, and kurtosis.

Comment 2# I could not find anything new on the importance of soil-moisture in the soil-stability. Please include a discussion on its importance and consider adding the provided references. Has soil-moisture been taken into account in your analysis?

Reply # Agreed, addition information is added in discussion part (L 332-336).

List of relevant new references (41-47)

41.   Tisdall, J.M. and Oades, J.M. (1982), Organic matter and water-stable aggregates in soils. Journal of Soil Science, 33: 141-163. https://doi.org/10.1111/j.1365-2389.1982.tb01755.x

42.   Gerard, C.J., The influence of soil moisture, soil texture, drying conditions and exchangeable cations on soil strength, Soil Sc. Soc. Amer. Proc. 29, p . 641-645, 1965.

43.   Haynes, R.J. and Swift, R.S. (1990), Stability of soil aggregates in relation to organic constituents and soil water content. Journal of Soil Science, 41: 73-83. https://doi.org/10.1111/j.1365-2389.1990.tb00046.x

44.   Fukumasu, J., Jarvis, N., Koestel, J., Kätterer, T., & Larsbo, M. (2022). Relations between soil organic carbon content and the pore size distribution for an arable topsoil with large variations in soil properties. European Journal of Soil Science, 73( 1), e13212. https://doi.org/10.1111/ejss.13212

45.   Yu, Q., Xu, L., Wang, M., Xu, S., Sun, W., Yang, J., Shi, Y., Shi, X., & Xie, X. (2022). Decreased soil aggregation and reduced soil organic carbon activity in conventional vegetable fields converted from paddy fields. European Journal of Soil Science, 73( 2), e13222. https://doi.org/10.1111/ejss.13222

46.   Le-Bissonnais, Y. (1996), Aggregate stability and assessment of soil crustability and erodibility: I. Theory and methodology. European Journal of Soil Science, 47: 425-437. https://doi.org/10.1111/j.1365-2389.1996.tb01843.x

47.   Karami A, Homaee M, Afzalinia S, Ruhipour H, Basirat S (2012) Organic resource management: Impacts on soil aggregate stability and other soil physico-chemical properties. Agriculture, Ecosystems & Environment, 148: 22-28. https://doi.org/10.1016/j.agee.2011.10.021

Comment 3# I could not find any information on the importance of the Long-Term-Dependence (or Hurst phenomenon) of precipitation, temperature and soil-moisture. This phenomenon is related to the high uncertainty and variability that these processes exhibit, and so, it is expected to affect the Long-Term soil-stability that the authors analyze. Please use the provided references to justify that this phenomenon exists in the above processes and that it is expected to affect soil stability. Since you analyze the Long-Term effect of nutrient supply on soil aggregate stability, then one should examine/mention/discuss the Long-Term effect of the climatic conditions, which are linked to the Hurst phenomenon.

Reply # Agreed, addition information is added in discussion part (L 372-381).

List of relevant new references (56-66)

56.     Pareek N. Climate change impact on soils: adaptation and mitigation. MOJ Eco Environ Sci. 2017;2(3):136-139. DOI: 10.15406/mojes.2017.02.00026

57.     Jones, D.L., C. Nguyen and R.D. Finlay, 2009. Carbon flow in the rhizosphere: Carbon trading at the soil-root interface. Plant Soil, 321: 5-33.

58.     Bot, A. and J. Benites, 2005. The importance of soil organic matter Key to drought-resistant soil and sustained food and production. FAO Soils Bulletin 80, Food and Agriculture Organization of the United Nations, Rome, pp: 78.

59.     Sarah, P. (2005). Soil aggregation response to long- and short-term differences in rainfall amount under arid and Mediterranean climate conditions. Geomorphology, 70(1-2), 1–11. 10.1016/j.geomorph.2005.03.007

60.     Zhang, S., Wang, R., Yang, X. et al. Soil aggregation and aggregating agents as affected by long term contrasting management of an Anthrosol. Sci Rep 6, 39107 (2016). https://doi.org/10.1038/srep39107

61.     Wang W, Chena WC, Wang KR, Xie XL, Yin CM, Chen AL (2011) Effects of long-term fertilization on the distribution of carbon, nitrogen and phosphorus in water-stable aggregates in paddy soil. Agric. Sci. China 10, 1932–1940.

62.     Bronick, C. J. & Lal, R. 2005. Soil structure and management: a review. Geoderma. 124, 3–22.

63.     Angers, D. A. 1992. Changes in soil aggregation and organic carbon under corn and alfalfa. Soil Sci. Soc. Am. J. 56, 1244–1249.

64.     Xie, J. Y. et al. (2015) Soil aggregation and aggregate associated organic carbon and total nitrogen under long-term contrasting soil management regimes in loess soil. J. Integr. Agr. 14, 2405–2416.

65.     Xie, H. T. et al. (2015) Long-term manure amendments reduced soil aggregate stability via redistribution of the glomalin-related soil protein in macroaggregates. Sci. Rep. 5, 14687(1–9) (2015).

66.     Ladd, J. N. (1989). The role of the soil microflora in the degradation of organic matter. In "Recent Advances in Microbial Ecology" (T. Hattori, Y. Ishida, Y. Muruyama, R. Y. Morita, and A. Uchida, eds.), pp. 168-174. Japan Scientific Societies Press, Tokyo.

Comment 4# Thank you for addressing this comment.

Reply # Thank you so much.

Comment 5# I could not find any experimental photographs of the samples used in the analysis. Can you please indicate where exactly these photos have been added?

Reply # For experimental photographs please see Figure 2 and soil samples used for soil analysis in Figure 3.

Comment 6# Thank you for your reply. I understand that you use linear relationships between different parameters, but a physical justification should accompany any choice of equations. For example, why do you think the correlation between microaggregate and macroaggregate fractions of soil aggregation, shown in Figure 6, is negative and not positive?

Reply # Agreed, results showed a strong negative relationship between the microaggregate and macroaggregate, because macroaggregate had higher SOC content and have the significantly higher stability as compared to microaggregate. Furthermore, the results suggest that aggregate stability and SOC content are highly correlated, and the percentage of both aggregate sizes (macro and micro) is highly influenced by the different nutrient supply options. Ladd (1989) found a direct correlation between texture and the portion of added C that went to soil organic matter rather than biomass.

Comment 7# Where is the M & M section that the authors refer to in their reply? The soil samples were taken at present and before 19 years?  Is it possible to combine all variables in a unique equation?

Reply # Pl see L 139-145. In this study we included only soil samples which was collected after completed 19 cropping cycle of rice wheat cropping system (i.e. May 2017, after harvest of wheat crop).