GIS-Based Evaluation of Soil Suitability for Optimized Production on U.S. Tribal Lands
Round 1
Reviewer 1 Report
In this study, the researchers used a digital elevation model and a fuzzy-logic based data mining approach to calculate and evaluate Dideriksen and Storie crop suitability indices.
This study is novel, but the problems are as follows.
1. The method section is obscure to read. Why not add a technical flow chart? The data sources of the parameters should be added to the model parameter tables (Table S1, Table S2).
2. The correlation between the Storie index, the Dideriksen index and corn yield is (Spearman rho = 0.16, p < 0.01), (Spearman rho = 0.02, p = 0.19) respectively. Their correlation is weak or even not statistically significant. Is the selected model assessment method reasonable?
Author Response
Reviewer 1
Comments and Suggestions for Authors
In this study, the researchers used a digital elevation model and a fuzzy-logic based data mining approach to calculate and evaluate Dideriksen and Storie crop suitability indices.
Response: Thank you for the time and consideration of our paper.
This study is novel, but the problems are as follows.
Response: Authors appreciate the comments provided. They are responded to directly below.
1. The method section is obscure to read. Why not add a technical flow chart? The data sources of the parameters should be added to the model parameter tables (Table S1, Table S2).
Response: Thank you for this comment. In general, digital soil property maps were developed and data used when available for model input (Storie and Dideriksen). After each crop model suitability was developed at the Tribal Nation-level, estimates were compared based on actual yield (n=>130,000) and CDL land-use information to evaluate yield gaps. Authors have altered and revised the methods section per this comment. Data sources were also added in S1 and S2. However, authors felt that a flow chart was not necessary however, if Reviewer 1 and the Technical Editor deem this necessary, it can be carried out in the next iteration.
2. The correlation between the Storie index, the Dideriksen index and corn yield is (Spearman rho = 0.16, p < 0.01), (Spearman rho = 0.02, p = 0.19) respectively. Their correlation is weak or even not statistically significant. Is the selected model assessment method reasonable?
Response: Thank you for this feedback. One of the study objectives was to compare model performance. Indeed, the Dideriksen did not have a significant relationship with observed yield and was therefore deemed inferior than the Storie model, which did have a positive relationship with yield. Verbiage was added to highlight this result in the amended version (L213-215).
Reviewer 2 Report
Dear Authors,
To begin with, congratulations on your interesting, well-organised, insightful analysis of the topic. To improve the quality of the paper, please include the following recommendations:
- The bibliography is not rich enough; try to search for more scientific papers concerning the analysed subject; In the 'Discussion' or 'Literature on the subject' (you could add it after the 'Introduction' section) the results of the analysis of the literature should be included;
- use more citations and references to the research conducted by other authors; have there been any other papers on the subject, what was the attitude of other researchers towards the problem, etc.;
- Line 92 – ‘was’ should be omitted;
- Line 109 – 110 – it would be better to use passive voice (more formal style) - To assess the modeled index results, the results from each index were compared with observed yields and with broad landscape patterns.’;
- Line 112 – remark as the one above – instead of ‘We plotted histograms of index values’ – ‘Histograms of index values were plotted (…)’;
- Line 113 – instead of ‘our study area’ - try to use ‘the following study area’ or ‘the study area’;
Best wishes,
Reviewer
Author Response
Reviewer 2
To begin with, congratulations on your interesting, well-organised, insightful analysis of the topic. To improve the quality of the paper, please include the following recommendations:
Response: Thank you very much for this thoughtful and kind comment, it is appreciated by authors.
- The bibliography is not rich enough; try to search for more scientific papers concerning the analysed subject; In the 'Discussion' or 'Literature on the subject' (you could add it after the 'Introduction' section) the results of the analysis of the literature should be included;
Response: Authors completely agree and apologize for this oversight. Because of the novelty of crop suitability models, particularly in the research area (US Tribal Nations), authors overlooked previous literature in this paper. This has been augmented in the revised version through adding several paragraphs (L300-310; L57-66) along with supporting citations.
- use more citations and references to the research conducted by other authors; have there been any other papers on the subject, what was the attitude of other researchers towards the problem, etc.;
Response: Agreed. This has been corrected in the revised version.
- Line 92 – ‘was’ should be omitted;
Response: Absolutely. Thank you for your attention to this, it has been carried out.
- Line 109 – 110 – it would be better to use passive voice (more formal style) - To assess the modeled index results, the results from each index were compared with observed yields and with broad landscape patterns.’;
Response: Agreed. This was altered per this request.
- Line 112 – remark as the one above – instead of ‘We plotted histograms of index values’ – ‘Histograms of index values were plotted (…)’;
Response: Apologies for the oversight in not using passive voice. This is corrected.
- Line 113 – instead of ‘our study area’ - try to use ‘the following study area’ or ‘the study area’;
Response: Thank you, this change was made throughout.
Round 2
Reviewer 1 Report
The authors did not explain the low correlation between the Storie index and corn yield (Spearman rho = 0.16). The correlation in literature [10] is 0.51. At least, the authors should have pointed out the limitations of these parameters in the discussion.
[10] A comparative assessment of land suitability evaluation methods for agricultural land use planning at village level
Author Response
The authors did not explain the low correlation between the Storie index and corn yield (Spearman rho = 0.16). The correlation in literature [10] is 0.51. At least, the authors should have pointed out the limitations of these parameters in the discussion.
Response: As stated throughout the original submission “Results showed observed yield was positively correlated with the Storie suitability index (Spearman rho = 0.16, p < 0.01), but not the Dideriksen index, suggesting the Storie index is more appropriate than the Dideriksen for modeling crop suitability in this area.” And “Spearman rank correlation demonstrated a positive relationship between corn yield and the Storie suitability index (Spearman rho = 0.16, p < 0.01), but the association between yield and the Dideriksen index was weak (Spearman rho = 0.02, p = 0.19) and not statistically significant at an alpha of 0.05.” Therefore, indeed there was a significant relationship between predicted and actual yield and consequently, results were appropriately interpreted that it was the superior Crop Suitability model between the two evaluated, which was an objective of this work. Further, the paper adequately described the assignment of variance among factors comprising the Storie model “The sum of the squared semi-partial correlation of the soil factors in the Storie index was 0.55, meaning factors included in the model individually accounted for 55% of variance in index values, and the remaining 45% of variance in Storie index values were the result of the relationship between multiple Storie soil factors.”
Despite this statistically positive relationship. Authors provided multiple suggestions for improving current models and directly pointed out limitations of the Storie model. For example, “Therefore, additional research is needed to assess these additional methods for crop suitability mapping in this study area. Finally, future work that develops empirical crop suitability indices explicitly for precision management applications in this area will be needed for optimization of crop production and more precise identification of yield gaps on U.S. Tribal Lands.” And again, “Further development of continuous maps of such important soil properties would therefore improve the overall accuracy of suitability indices at the landscape and field scale.” Nonetheless, authors have added additional statements regarding limitations to further placate this concern i.e., “However, despite the positive relationship between observed yield (>130,000 points within the Tribal Nation) and suitability predicted by the Storie index model, further work should be done to improve parameter development and ultimately yield correlations [10].”
[10] A comparative assessment of land suitability evaluation methods for agricultural land use planning at village level
Response: It is unclear what exactly is being requested here as this is not a complete sentence. Authors interpreted this comment as they should include some discussionary information, which was added in the revised version. These types of analysis are needed and becoming more and more advanced owing to computational capabilities. This paper is focused on this type of an assessment to improve farm operations at all scales, which is mandated by the US government and US federal funding agencies.
