Too Salty or Toxic for Use: A Tale of Starter Fertilizers in Agronomic Cropping Systems

Round 1

Reviewer 1 Report

The ms agronomy-2568056 with the title of Too Salty or Toxic for Use: A Tale of Starter Fertilizers in Agronomic Cropping Systems review an interesting topic, but the authors should revise my comments to make their ms suitable for publication in such high quality journal:

Abstract:

If possible the author can add some data as key results to show the important of their review ms.

L36-37 authors should cite this text using “Nano-Fertilization as an Emerging Fertilization Technique: Why Can Modern Agriculture Benefit from Its Use?”

Figure q should be revised and the text should be bigger to be clear for the readers.

Can authors add some sentences about the effect of COVID-19 on the productivity of N-P-K fertilization? Using some investigations such as: Will novel coronavirus (COVID-19) pandemic impact agriculture, food security and animal sectors?

L128-129 what was the type of the soil in “Corresponding findings indicated that broadcasting 22 kg ammonium 127 sulphate (AS) ha-1 was ideal for early rice establishment when applied prior to field flood-128 ing [41].”

L151 30% plant N or P uptake, so both N and P was uptake by same percent? What was the applied amount per ha in this study?

Please add the Latin name of plant species  in first mention

Please add the risks of NPK synthetic fertilizers

Please add the future research interests about this topic.

Good luck

minor revisions is need for English

Author Response

Round 1: Reviewer 1 Report

Response to Reviewer 1 Comments

Point 1: If possible the author can add some data as key results to show the important of their review ms.

Response 1: Line 17-18".........and these observations are corroborated by an analysis of past and ongoing short, medium, and long-term experiments."  A phrase was added in the abstract to justify the reported findings from the main document, thank you!

Point 2: L36-37 authors should cite this text using “Nano-Fertilization as an Emerging Fertilization Technique: Why Can Modern Agriculture Benefit from Its Use?”

Response 2: L36-37, Thank you for the proposition, we corrected it to [1,2].

Point 3: Figure q should be revised and the text should be bigger to be clear for the readers.

Response 3: Done.

Point 4: L128-129 what was the type of the soil in “Corresponding findings indicated that broadcasting 22 kg ammonium 127 sulphate (AS) ha-1 was ideal for early rice establishment when applied prior to field flood-128 ing [41].”

Response 4: adjusted to "Sharkey clay (very fine, smectitic, thermic Chromic Epiaquerts)"

Point 5: L151 30% plant N or P uptake, so both N and P was uptake by same percent? What was the applied amount per ha in this study?

Response 5: changed to "Likewise, Bermudez and Mallarino [50] globally obtained 27% early-season growth, 1.1% maize grain-yield increase, and 30% plant N and P uptake respectively." 30% was confirmed to be the mean N and P uptake. 

Point 6: Please add the Latin name of plant species  in first mention

Response 6: Done.

Point 7: Please add the risks of NPK synthetic fertilizers

Response 7: Risks in our case were linked to salt injury and ammonia toxicity.

Point 8: Please add the future research interests about this topic.

Response 8: Section 5.1 highlight all these future research interests.

Reviewer 2 Report

This review manuscript would add a lot to the existing body of knowledge in the area of soil fertility management and agricultural production. Soil fertility and fertilizer have become a global agenda in the fields of agricultural production and climate change mitigation. 

I have few comments:

1. make clear the methodologies, that is, how the literature were collected, thematized and analyzed.

2. make clear the continental coverage as there is enormous knowledge, management and requirement for fertilizers.

3. Make clear why the study is limited to NPK as there are also other forms of chemical fertilizers utilized in agriculture.

Author Response

Round 1

Reviewer 2 Report

Point 1. make clear the methodologies, that is, how the literature were collected, thematized, and analyzed.

Respond 1: This has been paraphrased in Figure 1. (A.) Authors keywords maps: Global network-overlay visualization of authors’ keywords co-occurrence and thematic evolution in research on starter fertilizer placement on agronomic crop production. (Map produced by VOSviewer); (B) Country collaboration network researching starter fertilization in agronomic crop production and productivity. A and B were prepared following the screening criteria of relevant papers about starter fertilizer toxicity, with a pertinent focus on fertilizer salt and ammonia toxicity. This resulted in generating a total number of 490 research articles reported in the Web of Science and Scopus out of which, 210 were universally related to all aspects of fertilizer toxicity on soil and crop production and productivity.

Point 2. make clear the continental coverage as there is enormous knowledge, management and requirement for fertilizers.

Respond 2: We generally covered this mainly in relation to starter fertilizer toxicity (fertilizer salt injury and ammonia toxicities).

Point 3. Make clear why the study is limited to NPK as there are also other forms of chemical fertilizers utilized in agriculture.

Respond 3: The manuscript has clearly detailed our main focus of starter N, P, and K and their combinations, especially in our introduction. We explained our limit to NPKs because of their strong linkage to crop injury during seed germination, emergence, and/or establishment, which at the same time is related to soil and crop behavior. These fertilizers' huge variability in terms of salt and ammonia production and toxicity levels; as well as misleading toxic fertilizer indexes due to new starter NPK fertilizers development in the industry significantly limit our focus to NPK. We are aware of other secondary and micronutrient elements that could be needed as starter fertilizers but globally, we opted to draw attention to NPKs considering the big changes in the industrial production processes.