Investigation of the Effect of Slurry, Combined with Inorganic N Rate and Timing, on the Yield of Spring Barley Post Cover Crop of Stubble Turnips

Round 1

Reviewer 1 Report

Review comments toward article titled Investigation of the effect of slurry, combined with inorganic N rate and timing, on the yield of spring barley post cover crop of stubble turnips submitted to Agronomy.

 

The article is in general, well written. The research had two experiments designed. The results were analyzed thoroughly through statistical methods to support or reject the hypotheses described. According to the article, this is the first field research on the effect of cover crops on N supply to the following commercial crop at Northern Ireland. The conclusion is significant in that due to regional high rate of mineralisation, neither organic manure or inorganic fertilizer are necessary for additional N when using stubble turnips as cover crop over winter for spring barley.

 

Line 12-13: Insert abbreviation with brackets ‘(NI)’ after ‘Northern Ireland’, as it first appears.

Line 15: No brackets needed for NI.

Line 44: Reference of Teixeira et al. 2016 is in a different format from other refs.

Line 127: ‘(Table A1.)’ shall be ‘(Table A1)’. Same format for tables and figures should be applied throughout the article.

Line 128: ‘Appendix (A.)1’ shall be ‘Table A1’.

Line 136: ‘..by drying at the samples...” shall be ‘…by drying the samples…’.

Line 146: ‘…the rates of N randomised across the rows..” shall be ‘…the rates of N were randomised across the rows…”.

Line 155-169: Please be consistent with the wording of ‘split-split plot design’.

Line 166-169: It would be good to have a table here showing the split-split plot design in order to compare with the randomized design in 2016/17. The simple description of two blocks and four treatments does not differentiate 2017/18 design from 2016/17 design at all.

Line 200: ‘dried for 80^oC’ shall be ‘dried at 80^oC’.

Line 203: Please check the formula of harvest index. Shall it be grain weight/(grain+straw+chaff weights)*100?

Lines 207-210: All tables for REML analyses for 2016/17 (3, 6, 8, 10) should have the Nitrogen Treatment described in this paragraph as the 170 kg N/ha treatment, as I read out of the text.

Line 220: ‘The 0 kg/ha rate led to the greatest grain yield, and a 70E+70L significantly reduced yield.’ This above is only shown in Figure 2 for 2016/17, not for 2017/18. Please emphasize that. In addition, this paragraph is best organized to describe 2016/17 and Table 3 only.

Lines 234-236: The content shall be incorporated in the caption of Figure 2. The same with lines 251-252 to Figure 3, lines 268-271 to Figure 4, and this applies to the rest of the article.

Lines 246&261: Please have the same number of digits for P-values in body text and in tables. The same applies to the rest of the article.

Lines 276-277: In ‘In 2016/17, when slurry was applied to the 0 kg/ha N plots, total N offtake increased by 29.2 kg/ha but, where 70 kg of inorganic N was applied to the 0 kg/ha N + Nil Slurry, N offtake was only increased by 13 kg/ha,’, amounts of changes in N offtake are not consistent with Figure 5 (right plot).

Line 365: ‘O N’ shall be ‘0 N’.

Line 368: Please check ‘the controls (0 N) No Slurry and Slurry (0 N)’.

Lines 381-382: Equations for Stem and Roots shall have one additional set of brackets.

Stem = 118 kg/ha N x [0.72 - (26.57 x 12.2/1000)]

Roots = 31.5 kg/ha N x [0.72 - (26.57 x 16.4/1000)]

 

Line 399: ‘that’ shall be ‘than’.

 

Section 4.2.1: Suggest to carry out the experiments in a few different regions of NI in order to quantify the rates of mineralization so as to better support the practice of reduced rate of N for NI.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

This study investigated the effect of pig manure slurry and synthetic N fertilizer rate and timing on spring barley following a stubble turnip cover crop in Northern Ireland. The study answered a question about fertilizer management given that a cover crop was already part of the cropping system. Unfortunately, it is not clear from the study description if the authors had "fallow" (no cover crop) check to compare N requirement with and without a cover crop. Notwithstanding, results of the study will be useful to growers in Northern Ireland. Below are some comments to improve the manuscript.

1. On line 15, "NI" is used, I assume as an abbreviation for "Northern Ireland". I suggest placing the abbreviation “NI” after Northern Ireland in line 12.
2. Lines 19 to 22 got me confused. Is this part of results of this experiment? It would be worth describing treatments/study to your audience earlier in the abstract before presenting results. The abstract is not clear on treatments and findings of this study and needs revision to provide clarity on study design, results and overall conclusions.
3. Line 43, this citation style is different from the others and will have to be changed.
4. Line 48, more information would be helpful for the non-UK readership who are unfamiliar with the RB209 Nutrient Management Guide, its purpose, and jurisdiction.
5. Line 71, this acronym has not be used previously in the text, so we do not know what it stands for yet.
6. Several instances, sentences were began with abbreviations. This should be corrected; you cannot begin sentences with abbreviations.
7. Line 117, the term "offtake" seems weird to me. I would prefer the term "uptake".
8. Line 126 to 127, adding the make and model for equipment used for slurry spreading and pigtail harrow may be worthwhile for the readership.

9. The ANOVA table presented in Table 4 does not seem appropriate for a split-plot design. Why separate Early N and Late N fertilizer application when the goal is to compare timing of N fertilizer application? The analysis should include slurry as whole plot and a sub-plot factor of timing of N fertilizer. Please clarify the treatment description and subsequent statistical analysis. 

10. Line 120 to 130, wondering why a control of no cover crops was not included as part of the study. A statement to indicate why a check of no cover crops was not included and provide a limitation of results of this study.
11. Figure 2 should be updated to specify figure 2a and 2b and reference them in the text. Similarly for figure 3.
12. Change Table 7 caption to “Analysis of variance of 2017/2018 grain quality parameters”.
13. Line 309, I am confused here, what is Chapter 4? Please clarify.
14. This is the discussion section, but a reference to new results is made (Table 11). This should remain in the results section.
15. Line 347, similar to above. New results should be in the results section rather than the discussion. Useful information (above was as well), but the placement should be in the results section.
16. Line 404, this is a good discussion on the possible reasons why some differences were not in fact observed in this study. I see that this is also mentioned in the conclusion so that is good too.
17. An unfortunate limitation for an otherwise a good study.
18. Line 491 to 494, this is a key takeaway from this study. It would appear that this system, winter barley/stubble turnips-spring barley, is effective at this study location given historic nutrient management that may be the case for others in the region. A version of this summary should be added to the concluding part of the abstract.

Author Response

Please see attached 

Author Response File: Author Response.docx