Soil Management Practices to Mitigate Nitrous Oxide Emissions and Inform Emission Factors in Arid Irrigated Specialty Crop Systems
Round 1
Reviewer 1 Report
This study reviews N2O emissions across a few specialty crop systems in California. They examine soil management practices, emission factor calculations, and to some extend gas sampling optimization. The topic is relevant, but the work is too centered around its relevance for California (e.g., CDFA Healthy Soils Initiative, research supported by Specialty Crop Block Grants, and other programs). It should either be broadened to a larger audience or submitted to a regional journal.
Broaden the audience of who will read and cite this paper. Pull back on the California focus to be relevant for a broader audience. Instead of the key-wording on ‘California’, consider centering on the climatic aspects so that other regions can relate (i.e., irrigated arid). Center this study as a model to standardize methods and EF calculations (corrected vs uncorrected) to be employed in other regions. Bring in how this can be relevant to other arid regions (e.g., Israel, South Africa). Regional journal: If this study has no value outside of California, it should be submitted to Geoderma Regional or California Agriculture.A few other suggestions:
Title: Add ‘specialty crops’ on the title to replace tomato, lettuce, wine grape and almond
Abstract:
L25-27: briefly mentioning how your numbers contrast with IPCC’s would be more informative.
Introduction:
Why are we looking into specialty crops? The abstract brings this information, but it should be brought into the introduction as well.
L38-40: The reader needs to be convinced that 7% of CA emissions and 8% of US Ag emissions is a big deal. Would these numbers become larger if N2O emissions are converted to C-CO2-equivalent?
M&M:
2.3 Did you ever validate the correction method with a study that had background measurements? If so, center the story around this and highlight this throughout the main parts of the manuscript. It would make this manuscript more. This would be helpful beyond the California setting.
Author Response
see attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper presents review scientific literature on impacts of soil management practices in California specialty crop systems on GHG nitrous oxide emissions. The paper is well written and presents valuable information about NO2 emission.
Author Response
see attachments
Author Response File: Author Response.pdf
Reviewer 3 Report
Reviewed manuscript “Soil management practices to mitigate nitrous oxide emissions and inform emission factors in arid irrigated tomato, lettuce, wine grape and almond systems” concern on topic problems, actual in global scale and my opinion is suitable for publication at Soil systems journal.
My opinion some parts require improvement, because they are incomprehensible to the mean reader, other need editorial improvement.
Subchapter 2.2. Overview for lettuce and grape was documented information from the references. For tomatoes and almonds no provided source of information.
Tables 1-4 they should be prepared according to the same scheme. Please explain why for table 3 only emission factors (seasonal and annual) presented without the delimitation on the uncorrected and corrected for background flux. Please explain why headings for table 2 is different compare to table 1and 4. Some editorial work must be done for table heading arrangement.
An identical term (corrected EF (%)) was used for two different equations (eq. 2 and 3).
Please correct sentence in row 156. "cover crop practice" tested not only in tomato system. Lettuce as well as grape review also included cover crop management.
Row 48 Explain what does mean CDFA abbreviation.
Row 273. Authors cited that few studies examine timing of N application and then only one study is cited [69].
Rows 293-294. Cited position 71 from references list. At the same row a different name was given (Burger et al.,).
Row 316. I suggest include statistical data base in references list.
Row 322. Given data (165 kg N ha-1) not correspond with data at table 1 (162 kg N per ha).
Table 1. Please include ”N" and "Y" in the legend below table explaining the used abbreviations.
Row 385 Cited position 85 from references list. At the same row a different name was given.
Row 429. Please check cited value of uncorrected EF. My opinion when 52 kg N per ha applied uncorrected EF was 9.69%.
Row 450. Please check, three number was given for two species (almond and walnuts).
Row 454. Please check reported value and assignment to fertilizers type.
Row 456. Number of applications not correspond with data at table 4.
Row 460. Change number of table (5 not 4).
Row 523. Explain what does mean WFPS abbreviation.
Row 541. Cited position 101 from references list. At the same row a different name was given.
Row 567 Lack of that data of corrected EF at table 1.
Rows 582-584. For two different fertilization input (252 and 280 kg N per ha) microsprinkler irrigation tested. Please more precise what treatment described.
Rows 625-627. Sentence is not clear. Please precise the effect of SDI on control weed densities?
Row 627 Explain what does mean UC abbreviation.
Row 650. Please check baseline state-wide N2O emissions with N2O emissions of tomatoes produced on reduced tillage with SDI and no cover crops.
Row 716. Please check emission increasing value (232).
Row 729 and 731 Lack of unit for CO2 eq yr-1
Row 750 Data of EF uncorrected N input for grapes not presented at table 2 but at table 3.
Row 753-756 Please add uncorrected state-wide N2O emission.
Rows 763-766 Both described systems for grape adopted cover crops.
Row 777 Data only presented at table 1-5. Please correct.
Many times, N2O was wrong written rows f.ex.: 572, 579, 623, 662, 716.
Please add bracket at row 65
Delete one word assume (row 183).
Delete "'s" row 651.
Delete "see below" and "discussed below" row 657 and 733
Please add space on over estimation (row 796)
Suggest delete all personal communication as a citation.
Author Response
see attachments
Author Response File: Author Response.pdf
Reviewer 4 Report
109: Did you include the fact that experiments which only sampled over a 2 month period are associated with a much higher uncertainty?
117-120: Reference missing (same 128-130)
182: Are N2O emissions really independent of the soil type? (see also 205)
184: Are there any references which support this assumption (in regard to N application)?
316: Are the calculations based on the recommended or on the actual rate?
376 delete “comparatively”
769: Are there any studies which assessed the influence of the soil type on the N2O emissions in order to say something about the uncertainty?
Author Response
see attachments
Author Response File: Author Response.pdf
