Assessment of Variation in Marginal Productivity Value of Water in Paddy Farming Systems in Times of Water Stress
Round 1
Reviewer 1 Report
Comments
SUMMARY
The paper addresses the research area related to Water Resources Management, Policy and Governance section in the MDPI Water journal. I believe that the target journal is an appropriate forum for this article. This study employed residual imputation method to isolate the marginal productivity value of water from other inputs of production in six paddy farming systems viz. the conventional transplant and flooding system (CTFS), system of rice intensification (SRI) and the mechanized systems under Kilombero Plantation Limited (KPL).
BROAD COMMENT
This study is of great importance for agriculture in Tanzania. The Introduction section is written with recent references. The methods were well described and in detail allowing a good understanding of the results of the study. The authors discussed well the results of the study. However, I have some concerns about the different parts of the manuscript. I suggest a minor revision to address a few issues. If the authors address carefully the comments, I’ll recommend publication of the manuscript in the journal.
SPECIFIC COMMENTS
- Line 237: the authors put the formula for the effective rainfall calculation for rainfall lower than 70 mm, however, from Figure 4, I noticed that most months have rainfall higher than 70 mm. Please, include also the formula used when P>70 mm
- Line 153: Pleas, use one citation style, this “Kangalawe and Liwenga (2005)” seems different from the others in the manuscript.
- Please, incude the implications of the findings of the study for agriculture in Tanzania (for policymakers) in the abstract as well as in the conclusion sections.
- Reading the manuscript, it is not clear whether the authors conducted experiements on field or not. If it is the case, put detail about the experimental design and data collected.
Comments for author File: 
Comments.pdf
Author Response
Hello,
Your invaluable comments/reviews are much appreciated. We have worked on them (attached file) and added details as per your comments. This included improvements in English, formulae, references, and improvement in the methodology where an explanation of the superiority of the residual imputation method over the change in net income for instance which lamps other inputs of production together with that of water – thereby exaggerating facts. Other rectifications have benefited from various comments as per the plagiarism check.
Thank you very much
Regards
Onesmo
Author Response File: Author Response.pdf
Reviewer 2 Report
Water productivity has not been considered in order to improve the decision-making process in water politics. This paper is a good example of using this tool, and I appreciate the effort of the authors.
One of the main keys in this kind of research is to evaluate changes or variations in this economically relevant factor. And It is very interesting how the authors have developed this challenge.
The information is very clear and it is correctly processed. The methodology is simple but correct despite certain factors. However, the weakness of this research is the economic productivity analysis. Physical Water Productivity is simple to measure and compare. Even for different climate areas. Economic Water Productivity depends on income and the difference against costs. The income depends on prices. And prices depend on markets.
The authors have not taken into account the direct profit calculation of the agricultural activity. They have selected an imputation approach method. Very useful when there is missing information or values. So, my question is: why this methodology and not others? Maybe, they cannot get income or market rice prices. It is not explained in the text.
Using an imputation approach method and no other methodologies should be clarified.
Author Response
Hello,
Your invaluable comments/reviews are much appreciated. We have worked on them (attached file) and added details as per your comments. This included improvements in English, formulae, references, and improvement in the methodology where an explanation of the superiority of the residual imputation method over the change in net income for instance which lamps other inputs of production together with that of water – thereby exaggerating facts. Other rectifications have benefited from various comments as per the plagiarism check.
Thank you very much
Regards
Onesmo
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
I have undertaken a review of the manuscript (revised) as well as the attached author responses to the initial review. I am satisfied with the revisions made by the authors as they have addressed most, if not all, of my initial comments. Therefore, I do believe that the manuscript has been significantly improved and now warrants publication in Water.
Comments for author File: 
Comments.docx
Reviewer 2 Report
I think it is well-conceived research work and very interesting for Water. I agree with this new improved manuscript. No objections.
