The Correct Cover Crop Species Integrated with Slurry Can Increase Biomass, Quality and Nitrogen Cycling to Positively Affect Yields in a Subsequent Spring Barley Rotation

Round 1

Reviewer 1 Report

This manuscript deals with the cover crpos species and slurry accumulation on barley yield. Cover crops were identified to have considerable potential for soil quality and other plants. But I have a question concerning the reasons of selection of cover crops for the study. I think that this choice should be describe in the manuscript. I also suggest to add to the title and also to the abstract information that these studies were carried out in pot experiment. I also reccoment to underline in the conclusions which the cover crop/s had the best effect on barley yield and other parameters. I suggest to add appropriate references to the section material and methods when Authors write about methods used for C, N and other parameters determination. I think that methods used in the study were not develop by the Authors.

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

The main topics of the MS, ie pig slurries' environmentally safe field application, has a medium to high scientific interest.

What makes this MS 'unique' or interesting,  is the Cover Crops data collected ( ie growth and nutrient uptake, weed control, water use and legacy effect on nutrients available for the next crop).

Some problem arise from the analysis of the data in the Result section.

In particular the authors don't show in the Result section a substantial data analysis, like the Apparent Nutrient Recovery (ANR),  to demonstrated that the Nutrient balances are environmentally better. Only in the discussionsection  they mention such aspects.

Adding a subsection and a graph presenting the ANR certainly will improve the MS.

For a standard data analysis using such N efficiencies  see:

Cavalli, D., et al. (2014). Italian Journal of Agronomy, 9(2), 71. https://doi.org/10.4081/ija.2014.567  

Zavattaro, L., et al (2017). European Journal of Agronomy, 90(July), 127–138. https://doi.org/10.1016/j.eja.2017.07.010)

Liu, J. et al (2018). Agronomy 2018, 8, 293.  

Moreover some details in Material and Methods are missing:

soil textural and chemical analysis;

the initial SoilMineralNitrogen (even if listed in the Discussion section);

how Water Holding Capacity was monitored and the additional water requirements (ie irrigation) were assessed;

row 150-153 it is not clear if authors incorporated or not into the soil the roots of Tillage radish; this make more difficult to interpret the large value of N uptake by Tillage radish. Moreover this tap roots removal is unrealistic from a real farm perspevtive.

In results section:

The rationale of data analysis is not straight and could make some confusion when looking at graphs titles not well described; eg Figure 3 and 4  don't say which slurry treatment is accounted for;

The list of CoverCrop species change in different graphs and this makes confusion;

The meaning of Total detectable N  is not well described, it is better to relate it to an explicit N balance equation;

The effect of weeds is assumed negligible on the N cycle, but this is not clearly demonstrated or explained in Result section as it is in Discussion section;

The discussion section has only one  misconceptions derived in the following rows:

Row 390: '... 1397.7 g/m2 of CO2 have been sequestered by the tillage radish...' . A more appropriate term should be up-taken .

Row 391-392- ' Whilst 60 % of this CO2 will be released within around  6 weeks as the crop decomposes, 40 % will be incorporated into soil organic matter [57]'; This introduces a misinterpretation of long term Soil Organic Matter  balance. Please correct this statement evidencing that the 40% (not mineralized C input after 6 weeks)  will contribute, even if at much lower extend,  to the long term SOM balance.

The rest of Discussion and Conclusion sections are well done and complete  

References: many items are not correctly entered. Eg in #6 & #15 source is missing. Please check .

Author Response

Please see the attachment

Author Response File: Author Response.docx