Pineapple Residue Ash Reduces Carbon Dioxide and Nitrous Oxide Emissions in Pineapple Cultivation on Tropical Peat Soils at Saratok, Malaysia
, Osumanu Haruna Ahmed 2,3,4, Nik Muhamad Nik Majid 5 and Zakry Fitri Abd Aziz 2Round 1
Reviewer 1 Report
This study deals with the question whether pineapple residue ash applied on tropical peat soils reduces C02 and N20 emissions during pineapple production. The study generated a variety of data, which need to be analysed with modern statistical methods to extract the best results from these data. The lack of the latter is the main shortcoming of the present study.
Introduction
Line 43: Please mention health risks for farmers as well as the population as well.
L 100: Give examples of alternative approaches to sustainably manage pineapple wastes.
Please give a definition of ash and distinguish it from (bio)char.
Material & Methods
L 128: Mean annual temperature? Please add.
L 150-156: Which gases and which quantities were released during ash production?
L 180: Recommended rate – what is meant by that? Please cite the recommendation.
Explain why 20 g ash were selected.
L 188: How was mixture applied on the soil? Explain.
L 197-199 (Table 1): Application rate: Explain, what is the unit (m2, ha, …) treated?
L 204: Replace “has” with “have”
L 261-266: The effect of six treatments (T1-T6) on repeated measurements (months 3, 6 and 9) of CO2 and N20 emissions is analyzed. A linear mixed effect model should be fitted to the data.
It is recommended to consult a statistician to get recommendations for the most suitable model.
In table 6 and figure 4 T1-T6 data are pooled. It seems incorrect to pool data if a significant effect of T1-T6 on CO2 and N20 emissions has been proven. A statistician should be consulted also on that issue.
Results
Table 2: Why are ammonium-nitrogen + nitrate-nitrogen higher than total nitrogen (%) at 0-20 and 20-40 cm soil depths?
Table 4: Values were obtained from which soil depth? Please indicate in figure captions.
Figure 3: Averaged CO2 and N20 emissions over all treatments? Please indicate in figure captions.
L 341: Replace “increased” by “increase”
Discussion
The discussion must be adapted to the results of the new statistical analysis.
The emission of gases during pineapple residue ash production should be discussed. These emissions would have to be included in a later CO2/N2O balance.
Author Response
Dear Reviewer,
The manuscript has been revised accordingly by addressing all the comments and suggestions received.
Please see the attachment for the point-by-point response to the comments.
Thank you.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Pineapple Residue Ash Reduces Carbon Dioxide and Nitrous Oxide Emissions in Pineapple Cultivation on Tropical Peat Soils at Saratok, Malaysia
Dear authors,
The topic of your paper is interesting, in a field in which better knowledge is necessary if we want to guarantee the sustainability of agricultural activity. However, there are some aspects which should be improved.
A.- Abstract & title:
Ok. The aim is clear
- Introduction:
The research question is clearly outlined.
Line 134: ginger (bentong variety) do you mean zinger officinale? Please, add the scientific name.
- M&M:
The variables are defined and neasured appropriately. Methods are valid and reliable.
- Results & Discussion:
Data in appropriate way. Figures and tables are ok. Discussion is supported by results or/and references.
- Conclusions/ Implications:
Conclusions are supported by results. However, there is some aspects which could be improved: It would be interesting some additional managerial implications in line with the findings of the study. Something to inspire implications for practice.
Further, sustainability of the pineapple residue ash application would need to be verified. Long-term soil monitoring (Soil microbiota / soil organic matter heterogenety / soil porosity, bulk density, etc.) would help to understand the process and its potential effects on the productivity and long-term sustainability of agricultural activity. Please, you should consider it or, at least, comment it ... to analyze it in the future.
- References:
Please be selective, but representative with referencing and include no more than 50-55 citations for a regular paper; depending on the research, it may be necessary to add more citations. 80 citations could be too many, are you sure that these citations are relevant to the present work? Are they all necessary? Further, the references are somewhat updated.
Author Response
Dear Reviewer,
The manuscript has been revised accordingly by addressing all the comments and suggestions received.
Please see the attachment for the point-by-point response to the comments.
Thank you.
Author Response File: Author Response.docx
Reviewer 3 Report
The manuscript entitled „Pineapple Residue Ash Reduces Carbon Dioxide and Nitrous Oxide Emissions in Pineapple Cultivation on Tropical Peat Soils at Saratok, Malaysia” presents interesting topic connected with sustainable crop production and mitigation of greenhouse emission s from agriculture.
The study was prepared using proper methods, however the field experiments were conducted only in one season. Usually in agronomical research experiments are repeated in two or more seasons (to examine various environmental effects, especially caused by weather variability). Could you explain if the field experiment in one season is enough for such kind of the study?
Please provide more details about ANOVA model used for the statistical analysis. It was multifactor model? Which factors were included in this model?
I recommend using colours for graphs. It will allow better readability of the figures in comparison to greyscale figures.
Some relationships presented in Table 6 despite of very low values of correlation coefficients are statistically significant. Please provide number of observations on which these relationships were evaluated. What was experimental unit in such analyses (one plot)?
Similar doubts I have for other results. Almost all results are characterized by very low variability. For example standard errors for fresh fruit weight (table 5) are very low, from 0.003 kg. Since standard error depends on number of observations in my opinion such number of observations should be provided with every table where standard errors are presented. For me it is quite strange that standard errors are very low for most of variables. Especially in field conditions where high natural variability is quite common. Could you explain why variability of almost all variables in the study was vary small?
Author Response
Dear Reviewer,
The manuscript has been revised accordingly by addressing all the comments and suggestions received.
Please see the attachment for the point-by-point response to the comments.
Thank you.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
No comments.
Reviewer 3 Report
Authors improved manuscript according all my comments. In my opinion current version of the manuscript can be accepted for publication.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
