Production Costs and Benefits of Japonica Rice in Mwea, Kenya

Round 1

Reviewer 1 Report

This study compares the production costs and profitability of locally grown Japonica rice and conventional rice, in the Mwea Irrigation Scheme site in Kenya. The figures of outputs, yields, production costs for Japonica rice are estimated from cultivations on experimental plots, while the figures for conventional rice are assessed from interviews of farmers. The study then compares the figures for these two types of rice and provides policy implications.
Major points
• More explanation or justification for the sample size should be provided, which seems rather small. Is it mostly to obtain more detailed and accurate information of a particular farm (which is possible by closely monitoring a small number of farms), rather than focusing on more representative figures (which require larger samples)?
• Given the small sample sizes, authors should also report the statistical significance of the differences between figures.
• More information is also needed regarding the comparability of the production environment for the two types of rice. For example, if local Japonica rice was grown on better plots than conventional rice (for example, soil quality, flatness/smoothness of surface that minimize land leveling requirement, proximity to and conditions of nearby irrigation canals, proximity to threshing or loading space, etc.), it may be difficult to compare the production costs and profits between these two types of rice.
• Relatedly, the manuscript can benefit from a little more discussion on the differences in sales price between the two types of rice. The locally grown japonica rice is 90KSh/kg, which is considerably higher than conventional rice (55 KSh/kg). Do you have any information as to whether this is because the former is purchased by MIAD and the latter is sold to the local open market? Perhaps, authors can cite a few papers showing that willingness-to-pay by local consumers is also higher for locally grown japonica rice than for conventional rice in Kenya or elsewhere.
• Similarly, more discussion on seed quality will be beneficial. Is it possible that, better quality seeds (such as certified seeds) were used for local Japonica rice, while seeds used for conventional rice were of inferior quality (obtained from informal markets, etc.)?
• The manuscript can also benefit from a little more discussion on what explains the differences in costs between local Japonica rice and conventional rice. For example, in Table 4, transplanting cots for S2 is almost twice higher than conventional rice. What may be the reason?
• Similarly, in Table 5, please discuss a little more about the difference in bird scaring costs between local japonica rice and conventional rice. Does a certain variety attract more birds than the other? A quick review of relevant literature to list a few hypotheses is recommended.
• Some of the justifications used in calculating Table 6 figures are also not very clear. For example, it states, “Labor costs for japonica rice were reduced by 5-18 KSh/kg”. Please describe how this figure of 5-18 KSh / kg was derived.
Minor points
• While the overall contents of the manuscript are clear, I think that the manuscript can benefit further from English editing, as I found wording and expressions in this manuscript rather different from most other research articles written in English. For example, in the abstract, the sentence “In order to solve this issue, varieties that generate novel and competitive value are expected to be different from conventional varieties.” is a little unclear. There are numerous examples like this throughout the manuscript.

Author Response

Response to the Reviewer 1

We thank the Reviewer for this pertinent comment.

Comment 1): More explanation or justification for the sample size should be provided, which seems rather small. Is it mostly to obtain more detailed and accurate information of a particular farm (which is possible by closely monitoring a small number of farms), rather than focusing on more representative figures (which require larger samples)?

Response: We thank the Reviewer for this pertinent comment. In order to provide more information on sample size more, we have added the explanation as follows;

Explanation about sample size of japonica rice (P.4.L.106-107):

“In Kenya, japonica rice is produced only by MIAD. All japonica rice grown during that crop season was sampled.”

Comment 2): Given the small samples sizes, authors should also report the statistical significance of the differences between figures.

Response: Thank you for the comment. The results of the t-test were described in the paper, though they were also shown in the Table 1 for clear understanding as follows (P.6.L.204 and Average unit yield of S1 and S2 in Table 1 were marked *.);

Table 1. Yield and unit yield of each plot.

*Significance at the 0.05 level by t-test.

Comment 3): More information is also needed regarding the comparability of the production environment for the two types of rice. For example, if local japonica rice was grown on better plots than conventional rice (for example, soil quality, flatness/smoothness of surface that minimize land leveling requirement, proximity to and conditions of nearby irrigation canals, proximity to threshing or loading space, etc.), it may be difficult to compare the production costs and profits between these two types of rice.

Response: We appreciate the highly suggestive comment. In accordance with the Reviewer’s comment, we have added to the following description of the comparability of the production environment for the two types of rice (P.7.L.226-239);

“The soil in the Mwea region is black cotton soil, which becomes very hard when it dries; therefore, during the land preparation stage, tillage was done with rotavators, followed by leveling with an animal. Threshing was done in the portion of the field harvested by combine harvesters, and loading was done where the combine harvesters entered and exited the field. There was no significant difference of these production environments between japonica rice and conventional rice. On the other hand, as shown in Table 1, three plots of japonica rice for each of S1 and S2 were established, and the unit yields were different. Although there was no difference in the production environment, as described above, the distance to the canal and the condition of the canal may have caused the difference in unit yield. The same ca be said about the relationship between japonica rice and conventional rice. In this case, the comparison of the yield of conventional rice to the yield of japonica rice was based on yield data of the whole country, making it less sensitive to the production environment, such as the distance to the canal.”

Comment 4): Relatedly, the manuscript can benefit from a little more discussion on the differences in sales price between the two types of rice. The locally grown japonica rice is 90 KSh/kg, which is considerably higher than conventional rice (55 KSh/kg). Do you have any information as to whether this is because the former is purchased by MIAD and the latter is sold to the local open market? Perhaps, authors can cite a few papers showing that willingness-to-pay by local consumers is also higher for locally grown japonica rice than for conventional rice in Kenya or elsewhere.

Response: We really appreciate this pertinent comment. we have added the explanation on the sales price of conventional rice at farmers as follows (P.6 L.209-212);

“The price of 55 KSh/kg of conventional rice is the broker’s purchase price, which is lower than the purchase price of the rice mill. Farmers lack the means to transport their rice to a rice mill, so they sell it to a broker who comes to the farmer and purchases it for cash at a lower price.”

Comment 5): Similarly, more discussion on seed quality will be beneficial. Is it possible that, better quality seeds (such as certified seeds) were used for local japonica rice, while seeds used for conventional rice were of inferior quality (obtained from informal markets, etc.)?

Response: Thank you for the comment. we have added the explanation on resources of seeds to clear seeds quality as follows (P.5 L.178-179);

“The conventional rice seed was produced by and purchased from MIAD, as was the japonica rice seed.”

Comment 6): The manuscript can also benefit from a little more discussion on what explains the differences in costs between locally grown japonica rice and conventional rice. For example, in Table 4, transplanting costs for S2 is almost twice higher than conventional rice. What may be the reason? 

Response: Thank you for the comment. In accordance with the Reviewer’s comment, we have clearly described the transplanting cost for S2 in Table 4 as follows;

Explanation about the transplanting cost for S2 in Table 4:

The man-day per ha of S2 was 58.0, and the unit labor cost was 350 KSh, so 20300KSh/ha. The unit yield of S2 was 3.77 tons/ha, so the labor cost was 5.38 KSh/kg. On the other hand, the man-day per ha of conventional rice was 50.0, and the unit labor cost was 350 KSh, so 17500KSh/ha. The unit yield of conventional rice was 6.07 tons/ha, so the labor cost was 2.88 KSh/kg.

Comment 7): Similarly, in Table 5, please discuss a little more about the difference in bird scaring costs between local japonica rice and conventional rice. Does a certain variety attract more birds than the other? A quick review of relevant literature to list a few hypotheses is recommended.

Response: We appreciate the highly suggestive comment. In accordance with the Reviewer’s comment, we have added the explanation on the difference in bird preference by variety as follows (P.10 L.335-336);

“Differences in the bird preference by variety, such as those reported for sorghum production [17], may also affect japonica rice.”

Comment 8): Some of the justifications used in calculating Table 6 figures are also not very clear. For example, it states, “Labor costs for japonica rice were reduced by 5-18 KSh/kg”. Please describe how this figure of 5-18 KSh/kg was derived.

Response: We thank the Reviewer for this pertinent comment. In accordance with the Reviewer’s comment, we have clearly described the evidence that the reduction in labor cost is 5-18 KSh/kg as follows;

Explanation about the reduction in labor cost is 5-18 KSh/kg:

As shown in Table 2, the labor cost of S1 is 19.36 KSh/kg and that of S2 is 41.19 KSh/kg. Table 6 shows the labor cost estimated after adjusting the same condition for bird scaring, which is 14.49 KSh/kg and 23.33 KSh/kg for S1 and S2, respectively. The difference between the original labor cost and the estimated labor cost for S1 is 19.36-14.49=4.87, and for S2 is 41.19-23.33=17.86, which is described as 5-18 KSh/kg.

Comment 9): While the overall contents of the manuscript are clear, I think that the manuscript can benefit further from English editing, as I found wording and expressions in this manuscript rather different from most other research articles written in English. For example, in the abstract, the sentence “In order to solve this issue, varieties that generate novel and competitive value are expected to be different from conventional varieties.” is a little unclear. There are numerous examples like this throughout the manuscript.

Response: Many thanks you for the comment. In accordance with the Reviewer’s comment, we have conducted an English editing to improve the wording and expressions in English.

Reviewer 2 Report

Reviewer View:
The paper raises important issues for cost-benefit analysis of rice production in Kenya.
I have tried to review the paper from the empirical contributions to the literature focusing on its contribution to international readers of the journal.
General: It is good to conduct a cost-benefit analysis for a new technology specific to a new crop variety. However, we should be very careful in the way we analyze the data and come up with a conclusion.
Major comments
• Mostly locally grown in the literature use the word conventionally, but in this article the word use is confusing. The new verities should not be named locally. please use the new technology on trial as “Japonica rice” or another given name.
• It is not clear there is a statically significant difference between “Japonica rice” and the conventional one 6.44 tons/ha and 6.07. The profitability is mainly because of the high market price which is already supported and stated …from page 3 line 54 -60 “ Although it is non-aromatic with a low yield, it has a higher market price than basmati rice, and so is an attractive variety whose production volume is forecast to increase in the future. This suggests that locally grown japonica rice is highly profitable and competitive, making it a promising crop for small-scale farmers” (see Mwangi et al., 2017)
Reference “Mwangi, M. K. Transformation in Mwea Rice Sector. Available online: https://www.maff.go.jp/primaff/koho/seminar/2017/at-tach/pdf/171030_03.pdf (accessed on 01 November 2017).”
• It page 3 line 57 stated that the “japonica rice is eaten by the Asian community in Nairobi”. Is that possible to know the reasons why the local people in Kenya (majority in number) not interested in japonica rice? Because of test difference? Because of high prices in which the local community cannot afford it? It should be clear.
• The results are in the experimental trial with a replication. However, the output might be different in on-farm trials with farm management. Have you tried on the “Japonica rice” on the farmers' field?
• From page 3 on line 48- 52 discussed “the main challenges for the domestic rice value chain in Kenya have been listed as lack of water for irrigation; inefficient water management; poor land productivity; high input costs; shortage of machinery; bird damage; low-quality seedlings/seeds; difficulties for farmers surrounding delivery to mills; and the fact that agriculture” It is not clear how the new variety overcomes these problems?
• High
• There is a problem of more damage by bird attack for S2 variety” page 6 line 196. How is sure that the “Japonica rice” is not also affected compared to the local verities? This is a serious case in which the rise producers adopt a new verity.
• In Table 3 there are different values sate for agricultural machinery service charge for the 3 verities. It is not clear why this charge is different accounting that it should be uniform.
• Please make your policy implication based on your finding. Your conclusion is more general and does not show your findings. Your main finding is that japonica rice has the same level of productivity compared to conventional rice, but it is profitable because of the high market price. Your finding supports Mwangi et al., 2017.

Author Response

Response to the Reviewer 2

We thank the Reviewer for this pertinent comment.

Comment 1): Mostly locally grown in the literature use the word conventionally, but in this article the word use is confusing. The new varieties should not be named locally. Please use the new technology on trial as “Japonica rice” or another given name.

Response: We thank you the Reviewer for the comment. In accordance with Reviewer’s comment, we revised the name of domestic japonica rice to “japonica rice” and we have explained it on page 2 line 55-56 as follows;

From:

Currently, domestic japonica rice is eaten by the Asian community in Nairobi.

To:

“Currently, domestic japonica rice (hereinafter, japonica rice) is eaten by the Asian community in Nairobi.”

Comment 2): It is not clear there is a statically significant difference between “Japonica rice” and the conventional one 6.44 tons/ha and 6.07. The profitability is mainly because of the high market price which is already supported and stated … from page 3 line 54-60 “Although it is non-aromatic with a low yield, it has a higher market price than basmati rice, and so is an attractive variety whose production volume is forecast to increase in the future. This suggests that locally grown japonica rice is highly profitable and competitive, making it a promising crop for small-scale farmers” (see Mwangi et al., 2017)

Reference “Mwangi, M. K. Transformation in Mwea Rice Sector. Available online: https://www.maff.go.jp/primaff/koho/seminar/2017/at-tach/pdf/171030_03.pdf (accessed on 01 November 2017)

Response: We really appreciate this pertinent comment. Mwangi reported that the market price was higher than basmati rice, but no specific price was given. We have added that to the introduction (P.2 L.56-58). We added a note in the discussion (P.6 L.222-225) that this paper supports Mwangi’s report because it reveals the selling prices of producers.

We have added that to the introduction as follows (P.2 L.56-58);

From:

Although it is non-aromatic with a low yield, it has a higher market price than basmati rice, and so is an attractive variety whose production volume is forecast to increase in the future [6].

To:

“Although it is non-aromatic and has a low yield, it has a higher market price than basmati rice (the exact price was not available) and so is an attractive variety whose production volume is forecast to increase in the future [6].”

Additionally, we have added the explanation on the statically significant difference between unit yield of japonica rice and that of conventional rice as follows (P.6 L.222- P.7 L.226); 

“Furthermore, the unit yield of 6.07 tons/ha for conventional rice was a United States Agency for International Development statistic and only provides a single unit yield for the whole country of Kenya. Therefore, a comparator with the japonica rice yield was unfortunately not available for assessment of statistical significance.”

Comment 3): It page 3 line 57 stated that the “japonica rice is eaten by the Asian community in Nairobi”. Is that possible to know the reasons why the local people in Kenya (majority in number) not interested in japonica rice? Because of test difference? Because of high prices in which the local community cannot afford it? It should be clear.

Response: Thank you for the comment. In accordance with the Reviewer’s comment, we have explained about the reason why the local people in Kenya not interested in japonica rice as follows;   

Kenyans prefer aromatic rice, but it is not clear why japonica rice is not yet widespread. Our next study will be to investigate the test of japonica rice.

Comment 4): The results are in the experimental trial with a replication. However, the output might be different in on-farm trials with farm management. Have you tried on the “Japonica rice” on the farmers’ field?

Response: We appreciate the highly suggestive comment. As Reviewer mentioned, verification by on-farm trial is very important. Japonica rice has not yet been test grown in farmer’s field. It is necessary to conduct on-farm trial with farm management and verify the results. This is one of the limitations of this paper. We have added this point on page 11 line 387-390 as follows;

“This test cultivation was conducted at the MIAD test farm. However, to determine the cost of production when farmers grow japonica rice, it is necessary to carry out trials in farmers’ field using their management practices. This is one of the issues that needs to be addressed in the future.”

Comment 5): From page 3 on line 48-52 discussed “the main challenges for the domestic rice value chain in Kenya have been listed as lack of water for irrigation; inefficient water management; poor land productivity; high input costs; shortage of machinery; bird damage: low-quality seedling/seeds; difficulties for farmers surrounding delivery to mills; and the fact that agriculture” It is not clear how the new variety overcomes these problems?

Response: Thank you for the comment. Although it is not a direct solution to these problems, the new variety will have a higher selling price for the producers, so the profit of the producers will be greater than that of conventional rice. 

Comment 6): “There is a problem of more damage by bird attack for S2 variety” page 6 line 196. How is sure that the “Japonica rice” is not also affected compared to the local varieties? This is a serious case in which the rise producers adopt a new variety.

Response: We deeply appreciate this pertinent comment. The survey revealed that the cost of bird scaring was different between S1 and S2 because the number of bird scarers was adjusted according to local conditions, the difference between S1 and S2 may be due to bird preference for these rice varieties, and the fact that the cost of bird scaring was higher for japonica rice means that bird preference for japonica rice may be greater than for conventional rice. The higher cost of bird scaring for japonica rice means that the birds preference for japonica rice may be greater than for conventional rice. Once the factors behind the higher cost of bird scaring and the measures to address them are clarified, it may be possible to further increase the net profits of japonica rice.

We have added the following note in (P.10 L.335-336) on the differences in bird preferences among varieties;

“Differences in the bird preference by variety, such as those reported for sorghum production [17], may also affect japonica rice.”

Comment 7): In Table 3 there are different values state for agricultural machinery service charge for the 3 verities. It is not clear why this charge is different accounting that it should be uniform.

Response: Many thank you for the comment. We have explained on agricultural machinery service charge for 3 varieties as follows;

The man-day per ha for S1 and S2 was 3.0 for tractors and 1.30 for combine harvesters, and the unit rent was 3500KSh for tractors and 4000KSh for combine harvesters, so 10500 KSh/ha for tractors and 11700 KSh/ha for combine harvesters. The total per unit area is 22200 KSh/ha. Since the unit yield of S1 was 6.44 tons/ha and that of S2 was 3.77 tons/ha, the agricultural machinery service charge for each is 3.45 KSh/kg and 5.89 KSh/kg. respectively.

On the other hand, for conventional rice, the man-day per ha was 2.5 for tractors and 2.5 for combine harvesters, and the unit rent was 4000 KSh for tractors and 6000 KSh for combine harvesters. The total rent per unit area was 25000 KSh/ha. Since the unit yield of conventional rice was 6.07 tons/ha, the agricultural machinery service charge was 4.12 KSh/kg.

Comment 8): Please make your policy implication based on your finding. Your conclusion is more general and does not show your findings. Your main finding is that japonica rice has the same level of productivity compared to conventional rice, but it is profitable because of the high market price. Your finding supports Mwangi et al., 2017.

Response: We appreciate highly suggestive comment. In accordance with Reviewer’s comment, we have added our finding to second and third paragraphs of the Conclusion and revised them as follows;

Second paragraph of Conclusion (P.11 L373-379);

From:

Within materials costs (included in production costs), agricultural machinery service charges are seen as problematic because of a shortage of tractors and combine harvesters. It would, therefore, be desirable if strategies and support are put in place by the government and aid agencies to increase the number of machines owned by individual farmers and the MRGM that are available to undertake contract work for farmers, as this would push down the service charge unit price.

To:

Within the materials costs (included in production costs), agricultural machinery service charges accounted for the largest proportion of the total cost for both japonica rice and conventional rice. Agricultural machinery service charges are problematic because of a shortage of tractors and combine harvesters. Therefore, it would be desirable if strategies and support could be put in place by the government and aid agencies to increase the number of machines owned by individual farmers and the number available from the MRGM, as this would lower the service charge unit price.

Third paragraph of Conclusion (P.11 L380-386);

From:

Within labor costs, the main rice cultivation tasks (land preparation, transplantation, weeding, and bird scaring) are carried out by hired laborers, and a rise in their wages is cause for concern. Therefore, promotion of mechanization of those tasks to improve their efficiency is necessary, and relevant investigation is expected, in conjunction with strategies and support aimed at increasing the number of machines available.

To:

Within labor costs, the main rice cultivation tasks (land preparation, transplantation, weeding, and bird scaring) are carried out by hired laborers. As this trend is the same as in the case of Tanzania, it is possible that this is a hired-labor trend common to the East Africa region. An increase in the wages of these laborers is cause for concern; therefore, promotion of mechanization of those tasks to improve efficiency is necessary, and relevant investigation, in conjunction with strategies and support aimed at increasing the number of machines available, is expected.

Round 2

Reviewer 1 Report

Thank you very much for addressing my comments. The manuscript has improved significantly and I do not have any further comments.

Reviewer 2 Report

Dear Authors,

Thanks for incorporating in the revised manuscript most of my comments and accounting for the limitation of the study. I wish to read the study focused on japonica rice data-based on-farm trials and farmers' practice!

Congratulation and Stay Safe!!