Ecotoxicological Assessment of a Glyphosate-Based Herbicide in Cover Plants: Medicago sativa L. as a Model Species

Round 1

Reviewer 1 Report

I am afraid to recommend this study as the mobilisation in plant and soil  is not very well established. It should have been done with isotope tagged glyphosate. There are studies that used non-radioactive C-13(2)-N-15-GLYP labelling in similar studies. As this is a controversial topic substantiating studies need to be sound enough scientifically to be published.and mere symptoms and plant based assays are not sufficient. 

Author Response

Dear Reviewer,

Please see the attached file named "Response to Reviewers".

Best regards,

Cristiano Soares

Author Response File: Author Response.docx

Reviewer 2 Report

Your paper is clearly written and presents a neat account of a simple experiment. The detailed biochem is not something I am that familiar with.
Some published reports have also looked at the impact on soil microorganisms, mycorrhiza, rhizobia, plant pathogens and earthworms. With biotic (and some abiotic) stress, the coumestan concentration in M. sativa can increase markedly and become critical for breeding livestock.
I have noted boron in the list of micro-nutrients whose uptake has been compromised according to some researchers.
My main comment is that while the rates are expressed accurately as glyphosate it is not glyphosate that you applied. The named product contains the Transorb II surfactant package and some research has found the surfactants to be more serious an impact on non-target plants than the glyphosate. It seems then that the discussion should recognise the product rather than the "a.i.", glyphosate?
The cultivar of Lucerne seed sown should be given. I note the seed was not inoculated. Would not that be the common practice? The seed appears to have been sown immediately after Roundup UltraMax application ?
Would soil organic matter content be a significant factor influencing residual effect?

Author Response

Dear Reviewer,

Please see the attached file named "Response to the Reviewers".

Best regards,

Cristiano Soares

Author Response File: Author Response.docx

Reviewer 3 Report

The authors described the concentrated-dependent effect of gly on plants. tHey cocluded that both roots and biomass are significantly affected by the concentrations used (especially after a limit).

Which was the rationale for using these concentrations?

Why the authors "incubated" the plants for 21 days? Did the authors observed any impact at 10 days? what is happening at 30 days

Author Response

Dear Reviewer,

Please see the attached file named "Response to the Reviewers".

Best regards,

Cristiano Soares

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Rebuttal of authors are not scientific enough to accept this manuscript. 

Author Response

Dear Reviewer,

Please see our detailed response in the attached file named "Response to the Reviewers".

Best regards,

Cristiano Soares

Author Response File: Author Response.docx

Reviewer 3 Report

The authors replied to reviewer's suggestions. The authors may incorporate the answers into the text

Author Response

Dear Reviewer,

Please see our detailed response in the attached file named "Response to the Reviewers".

Best regards,

Cristiano Soares

Author Response File: Author Response.pdf