Corn Stover Removal Responses on Soil Test P and K Levels in Coastal Plain Ultisols
, James R. Frederick 1, Don W. Watts 1, Thomas F. Ducey 1 and Douglas L. Karlen 2Round 1
Reviewer 1 Report
Dear Authors,
I revised the manuscript “Corn stover removal responses on soil test P and K levels in Coastal Plain Ultisols” submitted to the Sustainability Journal. The paper is very interesting. However, I have some concerns, which need to be addressed before considering for final publication.
Line 120: please specify types of mineral fertilizers P and K (trade name and mineral content in %)
Line 122. if possible, please indicate the number of FAO (early, medium, late) next to the variety name Dekalb C69-71.
Fig 1. and Fig 2. Titles above graphs are unnecessary. Captions under the graphs are sufficient.
Request to change the font (Palatino) on the graphs to suit the journal requirements.
Overall evaluation of the work:
The scientific hypothesis used in the work is correct.
The literature used in the introduction is current and very extensive.
Methods used to perform analyses (Mehlich method and others) well matched to the experiment.
The results obtained from years of research are presented in a clear and readable way in tables and graphs. I have no major objections to the form of presentation of the results.
The conclusions from the statistical analyses are correct.
The references used in the discussion is very extensive and new.
Conclusions of the research results are well described and supported by the resultant data.
In my opinion, the authors have many years of experience in research work on the extraction of plant raw materials for energy purposes and the impact of such action on the mineral composition of soil. The work is very well prepared in terms of the assumed experiment and elaboration of results. The work is a valuable addition to the research conducted in this field in other States of the USA (IA, IL, IN, MN, NE, PA, SC).
Maize is a species that leaves a large amount of organic matter in the form of straw after harvesting. Taking more than 50% of the straw from the field proves to be detrimental due to the removal of minerals: N, P and K. However, replenishment is quick and possible by balanced mineral fertilization. The replenishment of organic matter is much more difficult, and natural, organic fertilizers in the form of manure and plant composts must be used for this purpose.
An important research aspect for the Authors for the future especially on South Carolina soils is to conduct a study on the loss of organic matter and deterioration of soil microbial flora activity under the effect of taking corn straw for energy purposes.
In my opinion, it is very good that a further part of the research conducted by the team of Authors concerning other aspects of soil depletion caused by the use of corn straw for energy purposes has been published in the article „Carbohydrate and Nutrient Composition of Corn Stover from Three Southeastern USA Locations” Spyridon Mourtzinis, Keri B. Cantrell , Francisco J. Arriaga, Kipling S. Balkcom, Jeff M. Novak, James R. Frederick and Douglas L. Karlen
The results obtained during the research conducted over a period of 5 years by the team of authors may serve as evidence of soil mineral depletion as a result of too intensive harvesting of organic matter intended for energy purposes. This work can be used for further research and analysis by scientists in the field of agricultural economics, agricultural chemistry and bio-energy.
Greetings to the Research Team and wish them further success.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This manuscript reports valuable field data, useful for future sustainable production of corn. I judge there is no critical problem and this manuscript should be accepted, after the following are properly amended.
Line 56: It is better to describe reason or author’s interpretation why results are different depending on studies.
Line 115-116: please add information on replicate. How many cores were taken for each treatment?
Line 120: please describe the kind of P and K fertilizers. In addition, please show the values of Mehlich extractable P and K.
Line 179: If possible, please show the results of statistical difference in the amount of corn stover between years.
Line 233, 256 Figs. 1 and 2: The data in Figs. 1 and 2 derive from both results of P and K amount/kg soil and bulk density. Please mention differences in bulk density data among treatments. By doing this, the authors can discuss the effect of corn stover removal on soil physical property.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
