The Phosphorus Availability in Mollisol Is Determined by Inorganic Phosphorus Fraction under Long-Term Different Phosphorus Fertilization Regimes
, Naiyu Zhang 1, Yanhua Chen 1,3, Zhenhan Qin 1, Yuwen Jin 1, Ping Zhu 4, Chang Peng 4, Gilles Colinet 2, Shuxiang Zhang 1,* and Jin Liu 5,*Round 1
Reviewer 1 Report
This manuscript summarized a long-term field experiment on NPK and manure use affecting soil P fractions. The work is of interest to researchers and land managers and is publishable after revision though what is reported is knowledge in the public domain.
General comments: Various chemical and spectroscopic techniques were used to characterize soil properties, but the spectroscopic results were not fully used, as reflected in the abstract and conclusions. Think about omitting the methods and data that were not used.
Technical comments:
1. An emphasis is required in the discussion on SOM reducing active Fe and Al, thus making more soil P available to the crop.
2. If crop yield is available, a discussion on the link between the yield and available soil P will improve the merit of this manuscript.
3. Before submission, the revised manuscript must be checked by Grammarly or a co-author (Gilles Colinet) to minimize grammatical errors.
Author Response
General comments: Various chemical and spectroscopic techniques were used to characterize soil properties, but the spectroscopic results were not fully used, as reflected in the abstract and conclusions. Think about omitting the methods and data that were not used.
Response: Thanks, and the we reworded the abstract and conclusion.
- An emphasis is required in the discussion on SOM reducing active Fe and Al, thus making more soil P available to the crop.
Response: Thanks, we remodified the discussion part about the relationship between SOM and Fe/Al.
- If crop yield is available, a discussion on the link between the yield and available soil P will improve the merit of this manuscript.
Response: Thanks for the advice. Compare to CK treatment, long-term application of P fertilizer significantly increased available soil P and crop yield. In this study, no significant difference in crop yield was found between NPK and NPKM treatments during the whole fertilization periods. This lack of difference may be because the critical value of Olsen-P in the Gongzhuling soil was 13.3 mg kg−1; above this value, crop yield is little influenced by additional P and the extra P would likely remain in the soil [1]. This result has published in previous articles by authors [2]. Therefore, in this paper, the author focuses on the effect of fertilization regimes on the P fraction with three different analytical methods and its influence factors.
- Before submission, the revised manuscript must be checked by Grammarly or a co-author (Gilles Colinet) to minimize grammatical errors.
Response: Thanks for this suggestion. The manuscript had been carefully checked and polished up.
Author Response File: 
Author Response.docx
Reviewer 2 Report
I reviewed the article "The phosphorus availability in black soil is determined by inorganic phosphorus fraction under long-term different phosphorus fertilization experiments" and I found it interesting and well-prepared.
The methods selected by the authors are reasonable according to the actual state of knowledge in this field of study and were selected appropriately to the given research goal. The methodology section was well described. Results section was also prepared very good. Tables and figures are relevant and clearly presented. The descriptive part of the results section exhaustively describes the obtained outcomes. Statistical data processing is also clear. After analyzing the results and conclusions sections, it can be confidently stated which of the obtained results are significant.
Altogether novelty and significance of content, as well as scientific soundness of the manuscript, are on a high level.
Based on my experience I recommend given manuscript to be published.
The only flaw as I can see is overusing general term of black soils which I find not specific enough.
As far as I do understand soil nomenclature/taxonomy in China, as a soil scientist I can not agree, nor approve, naming the soil on which the experiment was conducted as "black soil" only. This is due to inexactness in soil taxonomy systems recommended by soil sciences societies. While taking into account soils from the same group or sub-type it is easy to draw contradictory conclusions on the exact soil type. It is very visible with so-called black soils which can be Phaeozem or Czarnozem based on WRB classification, or Mollisols based on USDA taxonomy, and still there are country/region specific taxonomy systems in which black soils reffers to more than one specific soil type. Thus I strongly believe that indicating only in [93] and [115] the proper referencing to the soil type is not enough to make the article most clear to understand.
Hence, I strongly recommend to change term "black soils" into Mollisols both in text and title.
Author Response
Hence, I strongly recommend to change term "black soils" into Mollisols both in text and title.
Response: Thanks. According to the suggestion we remodified the description of "black soils" with “Mollisols” through the whole paper with red colour.
Author Response File: Author Response.docx
