Comparison of Spectral Reflectance-Based Smart Farming Tools and a Conventional Approach to Determine Herbage Mass and Grass Quality on Farm

Round 1

Reviewer 1 Report

This study is considered to be meaningful in that it has devised efficient smart farming tools by comparing MSI acquired from UAV and NIRS on site. And the method and results of the study were also systematically written. In the conclusion, the limitations of this study were described, and it would be good to write specifically what kind of research is needed in the future.

Author Response

Comment 1: In the conclusion, the limitations of this study were described, and it would be good to write specifically what kind of research is needed in the future.

Answer 1: We inserted an additional sentence in the conclusions about future directions in MSI-model development: “… Further model development might therefore focus on extending the calibration dataset with respect to spatiotemporal diversity and include three-dimensional information such as grass height to mitigate limitations due to saturating reflectance…”. Line number (prior to accepting the track-changes): 584-586

Comment 2: Moderate English changes required

Answer 2: The manuscript was revised by a professional language correction service and the changes are highlighted by using the “track-change” function. Line number (prior to accepting the track-changes): Applies to the entire document

Additionally the authors propose four minor changes for clarity:

1. We added a “¹” to clarify the affiliation for the co-author Roy Latsch. Line number (prior to accepting the track-changes): 5 
2. We added “…at a spectral resolution of 3–2 nm…” and “…at a spectral resolution of 8 cm^-1…”. Line number (prior to accepting the track-changes): 219, 249
3. We added “…and expressed based on the organic matter content (ash-free dry weight)…”. Line number (prior to accepting the track-changes): 266-268
4. We deleted “…However, the effect might be masked by other sources of imprecision, such as the issue of generalizability that was explained above…” because the sentence came from an earlier version of the text. Line number (prior to accepting the track-changes): 468-470

Reviewer 2 Report

I list here below some minor comments to improve the presentation, but in general I would say that the manuscript requires minor revisions only.

Please insert a new Table to list the abbreviation. It will really help the reader to have all of these defined again in one place.

3.3 Performance of the MSI-model
Are those correlation coefficients significant?
Could you add that information in Figure 4 and 5?

Table 4
Do the values after +- mean the standard deviation or the standard error?
Please mention in the caption.

Author Response

Comment 1: Please insert a new Table to list the abbreviation. It will really help the reader to have all of these defined again in one place. 

Answer 1: As all main abbreviations are summarized in Table 1, and, additionally, in all Tables and Figures the abbreviations are also explained, we have refrained from including a new table listing all abbreviations. However, if you insist, we are happy to include the table. 

Comment 2: 3.3 Performance of the MSI-model: Are those correlation coefficients significant? Could you add that information in Figure 4 and 5?

Answer 2: Thank you for pointing this out. All correlations are significant. We added this information in Figure 4 and 5 by using stars and explained the significance codes in the captions. Line number (prior to accepting the track-changes): 354, 405

Comment 3: Table 4: Do the values after +- mean the standard deviation or the standard error? Please mention in the caption.

Answer 3: The values indeed mean the standard deviation. We added this information in the caption according to your comment and wrote “Table 4. … (mean ± standard deviation) …”. Line number (prior to accepting the track-changes): 411

Additionally the authors propose four minor changes for clarity:

1. We added a “¹” to clarify the affiliation for the co-author Roy Latsch. Line number (prior to accepting the track-changes): 5 
2. We added “…at a spectral resolution of 3–2 nm…” and “…at a spectral resolution of 8 cm^-1…”. Line number (prior to accepting the track-changes): 219, 249
3. We added “…and expressed based on the organic matter content (ash-free dry weight)…”. Line number (prior to accepting the track-changes): 266-268
4. We deleted “…However, the effect might be masked by other sources of imprecision, such as the issue of generalizability that was explained above…” because the sentence came from an earlier version of the text. Line number (prior to accepting the track-changes): 468-470

Reviewer 3 Report

The authors of the manuscript entitled “Comparison of spectral reflectance-based smart farming tools and a conventional approach to determine herbage mass and grass quality on farm” present an interesting approach to evaluate the ability of two smart farming tools to determine the herbage mass and quality of multi-species grasslands. More specifically, the authors compared a UAV-based multispectral imagery model, a NIR spectrometer portable instrument, and the conventional method for measuring herbage quality with look-up tables.

The manuscript is very well-written, and it is clear that the study was very carefully planned. The descriptions of methods, tools used, etc., are very detailed and precise, the results are very clearly presented, and the discussion is elaborate.

The only minor issue is the lack of punctuation and other minor mistakes in certain parts of the text (i.e. P. 3 “If calibrations…generalize the results”, P. 6 “herbage sampling…metal cylinder”, P. 7 “To determine… into account [35]” ).

Overall, this manuscript is of very high quality, and with some minor changes will be ready for publishing.

Author Response

Comment 1: The only minor issue is the lack of punctuation and other minor mistakes in certain parts of the text (i.e. P.3 “If calibrations…generalize the results”, P.6 “herbage sampling…metal cylinder”, P.7 “To determine…into account [35]”).

Answer 1: The manuscript was revised by a professional language correction service and the changes are highlighted by using the “track-change” function.Line number (prior to accepting the track-changes): Applies to the entire document

Additionally the authors propose four minor changes for clarity:

1. We added a “¹” to clarify the affiliation for the co-author Roy Latsch. Line number (prior to accepting the track-changes): 5 
2. We added “…at a spectral resolution of 3–2 nm…” and “…at a spectral resolution of 8 cm^-1…”. Line number (prior to accepting the track-changes): 219, 249
3. We added “…and expressed based on the organic matter content (ash-free dry weight)…”. Line number (prior to accepting the track-changes): 266-268
4. We deleted “…However, the effect might be masked by other sources of imprecision, such as the issue of generalizability that was explained above…” because the sentence came from an earlier version of the text. Line number (prior to accepting the track-changes): 468-470