Field Validation of the DNDC-Rice Model for Methane and Nitrous Oxide Emissions from Double-Cropping Paddy Rice under Different Irrigation Practices in Tamil Nadu, India
, Shigeto Sudo 1, Tamon Fumoto 1,*, Kazuyuki Inubushi 2, Keisuke Ono 1, Akinori Yamamoto 3, Sonoko D. Bellingrath-Kimura 4,5, Khin Thuzar Win 6, Chellappan Umamageswari 7, Kaliappan Sathiya Bama 7, Marimuthj Raju 7, Koothan Vanitha 7, Palanisamy Elayakumar 7, Venkatachalam Ravi 7 and Vellaisamy Ambethgar 7Round 1
Reviewer 1 Report
This study evaluated the effect of continuous flooding and alternate wetting and drying on methane and nitrous oxide emissions in rice in India, and used the field data to validate the DNDC model. The study reports very interesting data on how reduced water use through alternate wetting and drying can reduce methane emissions and global warming potential despite increasing nitrous oxide emissions. The study also brings out the deficiencies of the DNDC model in predicting both methane and nitrous oxide under certain field conditions. The study was well conducted and generally well written. The authors need to work on the minor issues highlighted below before the manuscript can be published.
L73:……….. "it will be high uncertainties in" should be "will lead to high uncertainties in"
L93 in a pot experiment
L97: please rephrase as follows: …….were to assess; 1) whether CH4 and N2O…………; 2) the reliability……….
L110: Soil type is (not was)
Table1: planting date for summer rice 2016 should be 10/6/2016 (not 3016)
L190: delete therefore.
L245-246: Please rephrase the sentence/grammar
L247: that that, delete the repeated word.
L316-317: Delete “The” at the beginning of the sentence.
L365: Delete the word “with”
L370 "model needs to revise" should be "model needs to be improved"
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The article investigates an interesting topic related to methane and nitrous oxide emissions under different irrigation practices in double-cropping paddy rice by comparing two-year field data with the simulated results of the DNDC-Rice model.
The manuscript is clear and well written; however, some minor improvement and clarifications are needed.
Lines 97-100: the objective of the study need to be rephrased, as it doesn’t read well.
Lines 108-110: the absolute maximum and minimum air temperatures are not very informative of the meteorological conditions at the field experiment. I would suggest replacing it with average maximum and minimum air temperatures. In addition, it would be useful to get the same indicators (temperatures and precipitations) for the two different rice seasons from planting to harvest (summer and monsoon rice).
Lines 190-192: it is not the model per se that need to calibrate its functions to determine the partitioning of the photosynthetic product. Researchers instead should conduct this calibration/improvement of the model. The authors need to explain why this was not conducted in this study.
Lines 370-371: Same as above applies also for the soil redox status for better prediction of CH4 fluxes.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
