Adjusting Ceptometer Data to Improve Leaf Area Index Measurements
Round 1
Reviewer 1 Report
General comment:
The topic is certainly of high interest for agricultural research as the LAI is the main driver for biomass growth influencing light interception and in turn carbon assimilation. The manuscript is in general well written.
However, the substance of the study is too little. The need for corresponding measurements at low and high PAR to derive and apply the correction equations is not very convenient. Finally, the improvement for LAI prediction based on ceptometer measurements and correction equation are very minor, even though significant.
I suggest a deeper analysis into the parameters for each measurement (fb, PAR) and e.g. a dynamic value for X changing with growth stage (or LAI). X (and the solar angle) is mainly defining the extinction coefficient, which is changing during LAI evolution due to different canopy structure, an equation capturing this would be a way for substantial improvement.
Specific comments:
31: I suggest „canopy light interception“ 35: Delete two times “the” 45: samplings 85: papers 87-89: Rephrase, e.g. “Note, that high solar elevation does not imply high PAR during cloudy days ….. .” 92: I suggest to delete “: it could mean…. .” or rephrase 93: I suggest : “…both under diffuse and direct light,…” 95: Reword “hold” 98: “are expected” 122: “in Figure 1” 138: Use abbreviation: “PAR” 166: “leaf movement” 189-191: Isn´t this the same like measurement (1) ?Results: I suggest adding for each chapter of results the corresponding measurement of Material&Methods. The explanation of the measurements was quite hard to grasp, so relating measurements to results here, helps the reader to comprehend better what was done.
Figure 3 and other figures: I suggest to change the axes: Finally you want an accurate prediction of the “real” destructive LAI (y-axis), so your input is the ceptometer-LAI (x-axis).
225: The abbreviation “cc.” is not usual. Please choose different or simply write “circa” 231-232: Please re-word “…data-pair defined linears”. I don´t get it.-> in general: “linear” is not a noun, I suggest to re-word, e.g. “lines” or where applicable even more precise “regression lines”,..
232-233: What does this mean “assuming that the LAI values obtained at higher PAR values are closer to the real LAI”? How it this assumption taken into account in the regression? 234-235: What does this mean “maximizing the PARhigh value in 1700 μmol m-2 s-1”? You excluded the LAIs measured at above 1700? I suggest to re-phrase for more clarity.Figure 7: Actually, the prediction based on raw data is already very good. How do these values correspond to Figure 3, where the prediction was very bad and only high LAI values?
266: “…. studies investigating the reliability ……” 265-291: Most of this part can be essentially moved to the introduction. The first own results are discussed in l. 291.
Author Response
Response is attached in a separate file.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The article makes an analysis of how the lighting conditions affect the measurements of leaf area index with the ceptometer instrument. The article is very interesting and useful, since the correct taking of field data is vital for any type of agronomical studies. All article sections are very well explained and detailed, mainly the comparative analysis that is made with the results of other articles. Only to point out certain aspects to improve the article in general terms:
Review the article title. Some writing errors throughout the article. Add summary table in Results section compiling all the field information. Add the specific statistics obtained in Results section, as in Figure 3. Explain more why the limits of LAI = 4 (wheat) and LAI = 2 (maize) have been set in Section 3.3.
Detailed comments can be found in the attached document.
Comments for author File: 
Comments.pdf
Author Response
Response is attached in a separate file.
Author Response File: Author Response.docx
