Co-Cultivation and Matching of Early- and Late-Maturing Pearl Millet Varieties to Sowing Windows Can Enhance Climate-Change Adaptation in Semi-Arid Sub-Saharan Agroecosystems

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper is focused on the possible improvement of pear millet yield in Northern Namibia’s semi-arid region through appropriately matching 2 varieties to sowing time. From crop models simulations, it has been shown that global crop yields can be lifted by timely adaptation of growing periods to climate change (Minoli et al., 2022). In the present paper, yield data from a 2-year field experiment corroborate this hypothesis. For the studied years (2017-1018 and 2019-2020) rainfall has been rather limited, so the results can be expected to reflect drought occurrence probability and future climatic conditions in Northern Namibia.

Yield improvements can be expected from the introduction of new varieties : in the past ; yield has been doubled in Namibia through the introduction of Okshana-1 variety (CTA, 1992). Results of this paper suggest that the optimized use of 2 varieties, with different sowing times and growing length periods, could mitigate climate change effects.

Some questions arise from the expected adoption of this technique by farmers:

- High yield have been obtained in on-station conditions (maximum = 9.5 t/ha with Kantana, and 8 t/ha with Okshana-2) ; it would be interesting to know mean yields obtained nowadays by farmers, and to compare with the situation in 1993 described by Matanyaire (1996) : A large pearl millet grain yield gap was identified with on-farm yields of 0.15 to 0.20 t/ha, compared with on-station yields of 3.63 to 3.87 t/ha during the 1992/93 season.

- What are the respective areas actually sowed by farmers for Kantana, Okshana-2, and other varieties ?

- What is the average sown area per household ? What is the proportion of farmers able to sow 2 varieties of pearl millet ? What about the respective use of manure and chemical fertlizers by farmers ?

- It seems that the farmers identify short duration as the most preferred varietal trait above grain yield (Matanyaire, 1996) : because of rainfall variabilty , what is the probabilty of adoption of early sowing date of Kantana variety ?

References :

Matanyaire C. M., 1996 – Pearl millet production system(s) in the communal areas of northern Namibia: priority research foci arising from a diagnostic study. Pages 43-58, in Drought-tolerant crops for southern Africa, Proceedings of the SADC/ICRISAT Regional Sorghum and Pearl Millet Workshop, 25-29 July 1994, Gaborone, Botswana (Leuschner K. & Manthe C. S., eds.). Patancheru 502324, Andhra Pradesh, India: International Crops Research Institute for the Semi-Arid Tropics.

Minoli S., Jägermeyer, J., Asseng S., Urfels, A., Müller C. , 2022 – Global crop yields can be lifted by timely adaptation of growing periods to climate change. Nature Communications, 13, 7079. https://doi.org/10.1038/s41467-022-34411-5 .

 

Comments for author File: Comments.pdf

Author Response

We are grateful for the professional review. Kindly receive attached the rebuttal.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The overall results of this study are quite satisfactory, and the content, including the methodology, results, and discussion, is well-written.

However, there seem to be some areas that require modification, and I kindly request that you consider the following points:

The Introduction section appears to be lengthy. For instance, the 2nd, 3rd, and 4th paragraphs discuss the impacts of climatic changes on meteorological variations and crop growth, which could potentially be condensed into a single paragraph. This is just an example, and I anticipate that the author will exercise editing to ensure that the content fits within two pages.

Figure 2's precipitation data seems to be organized into a single data point per year, making the "scatter" format unnecessary. It might be more suitable to represent this information using a bar graph instead. Please consider changing the format accordingly.

As for Figure 3, while it appears to have some significance, considering the already substantial number of figures and tables in the manuscript, it might not be essential to include this figure. This is because Figure 2 already provides an insight into the irregularity of annual rainfall, implying that the monthly comparison results for each year would also be irregular. Nevertheless, if this graph is deemed essential, it could potentially be included as supplementary material.

Table 3 seems to have a distinct format from the others. Please ensure consistency in the formatting of tables.

Author Response

We are grateful for the professional review. Kindly receive the attached rebuttal

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript demonstrates a commendable level of scientific rigor and clarity. The presentation of the research is well-structured, making it easy for readers to follow the logical progression of the study.

The use of appropriate terminology and clear explanations reflects a strong grasp of the subject matter. This clarity enhances the accessibility of the work to a wider audience, including both experts and those new to the field.

The incorporation of relevant data, figures, and tables greatly strengthens the evidentiary foundation of the study. The visual aids effectively complement the text and provide valuable insights into the findings.

The manuscript also showcases a thorough understanding of the existing literature. The literature review is comprehensive and effectively situates the research within the broader context of the field.

Furthermore, the methodology section is robust, detailing the experimental design in a way that allows for replication and validation by other researchers.

In summary, the manuscript is a well-crafted piece of scientific work that exemplifies the hallmarks of sound and logical research. The attention paid to detail, clarity of expression, and methodological precision contribute to a valuable addition to the scientific literature. Kudos. 

Meanwhile, I'll suggest the use of the same citation format for the entire manuscript except where the journal says otherwise. In the introduction, direct names of the authors were given, while this changed from materials and methods to another format. 

Author Response

We are grateful for the professional review. Kindly receive the attached rebuttal

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The paper titled „Co-cultivation and Matching of Early- and Late-maturing Pearl  Millet Varieties to Sowing Windows can Enhance Climate-3 Change Adaptation in Semi-arid Sub-Saharan Agroecosystems“ solves very important topic of climate change effect on growing season and sowing time of  Pennisetum glaucum in Namibia.

 

The main question addressed by the researchers is to analyze rainfall patterns and trends, and their implications on the growing season of pearl millet. Furthermore, the importance of the optimal sowing window for the semi-arid NCR area in Namibia was evaluated.

  The topic is relevant in this research field, there are several studies with similar topic in other African countries but not much in Namibia. Furthermore, there is a high density of population in Namibia, livehoods of farmers depend on agriculture, and pearl millet is the dominant crop in the local agroecosystem. It is important to address this issue.

 

Part of the analyzes was performed only in two summer-rainy seasons – in this part I recommend to prolong this period to obtain more statistical significant results in their future research.

 

The paper is well done, it is easy to read and contains appropriate amount of tables and figures. The latest statistical methods were used for the analysis.

 

 

The discussion is conveniently divided into several parts (Weather conditions, Crop performance, Optimal sowing window for the NCR, and Agronomic significance) which improves its readability.  

 

All figures and tables are clear. Please, use bar chart in Figure 2 and  Figure 3 – this is a commonly used method in climatology.  And please, indicate the statistical significance in table 2.

 

In section Results, I suggest changing the numbering (line 360-361)…3.1 Weather conditions; 3.1.1 Descriptive statistics for annual and monthly rainfall…etc.

 

The most important findings are summarized in the conclusions – they are consistent with presented results and posed the objectives.

References are appropriate for this kind of research topic.  

 

 

I recommend to publish this paper in this form with the minor changes mentioned above.

 

Author Response

We are grateful for the professional review. Kindly receive the attached rebuttal

Author Response File: Author Response.pdf