Detecting Long-Term Dry Matter Yield Trend of Sorghum-Sudangrass Hybrid and Climatic Factors Using Time Series Analysis in the Republic of Korea
Reviewer 1 Report
The article is focused on a design of the model for determining the influence of climatic factors on the dry matter yield trend of Sorghum in the Republic of Korea. To evaluate the seasonality of long-term dry matter yield trend, the authors used the ARIMA method with the extended DickeyFuller test, and the correlogram of autocorrelation. The study covers during 1988-2016. The collected data consisted of dry matter yield data, seeding-harvesting dates, major cultivars including Jumbo and SX-17 and the growing area from April to September. The climatic data concerning to growth and development of the sorghum-sudangrass hybrid were collected on the basis of the year of cultivation, seeding-harvesting date and place, where the cultivation was carried out on the site of the Korean Meteorological Administration. The final set of data based on the assumption of normality was 420, using box-plot analysis using SPSS 23.0. Among the climatic variables related to the growth and development of sorghum were the average cumulative mean temperature, seeding-harvesting mean temperature, seeding-harvesting precipitation amount, seeding-harvesting precipitation days and seeding-harvesting duration of sunshine. The climatic factors found using the ARIMAX model indicate that seeding-harvest precipitation amount and accumulated temperature have a significant effect (p<0.05) on="" the="" dry="" matter="" yield="" of="" sorghum.="" results="" further="" indicate="" that="" seeding-harvest="" duration="" sunshine="" has="" no="" significant="" effect="" p="">0.05) on dry matter yield of sorghum. This does not mean that the average temperature and duration of exposure to sunshine do not affect the growth and development of sorghum, instead, the amount of precipitation together with the accumulated temperature during the seeding-harvesting season has the greatest impact on the dry matter yield trend. The results are the impact of the rainfall model as a major factor (from April to September) for the long-term trend of dry matter yield of sorghum in the Republic of Korea.
Ø Due to the predominant climate change and increasing average annual temperature, the article is a contribution to research.
Ø The authors use more shortcuts and the reader is lost in the text.
Ø I recommend extending the abstract.
Ø Material and Method - Subchapter 2.1 Time Series Data Collection - - I would like to explain in more detail the data obtained in individual years. The description of a particular selected crop (sorghum-sudangrass hybrid (SSH)) is inadequate - I propose to supplement its cultivation conditions and average yields. I propose to add individual hypotheses in this chapter.
Ø The title of article does not fully reflect the text. The result is the creation of a model equation.
Ø The conclusion is non-complaining. I recommend extending the overall model and study benefits.
2-4 - I propose to rename the title
115 - 118 - to explain the"d" shortcuts,
156 - Add to the "MaxAE" shortcuts description
Response to reviewer 1 comments
We very much appreciate the reviewer for detailed comments on our manuscript. He suggested to correct some areas in the manuscript. We found the points raised important and we did accordingly. In the manuscript where the changes are made highlighted with truck changes.
Point 1. The authors used more shortcuts and the reader lost in the text
Response 1. As per the reviewer recommendation, we have extended the areas where we felt the short cuts prevailed.
Point 2. I recommended extending the abstract
Response 2. We found that the shortcuts happened more of in the abstract part. Hence, based on what we received from the reviewer, we amended the abstract part significantly and hope this provides clear understanding to the reader. The changes made in the abstract were given with colored highlight or truck changes. Due to restriction in the number of words in this section, we obliged to focus on the exact flow of the work so us to make clear for the reader, but we met what the reviewer demanded.
Point 3. Materials and Method – subchapter 2.1. I would like to see more detailed data obtained to be explained in individual years. The description of a particular selection crop (sorghum-sudangrass hybrid (SSH)) is inadequate – I propose to supplement its cultivation conditions and average yields. I propose to add individual hypothesis in this chapter.
Response 3. Detailed data collected in individual years presented in the Materials and Method section in subsection 2.1. The description of SSH including the cultivation condition is given on the introduction part (we felt that the appropriate place is in the introduction section and have a look in the second paragraph).
Point 4. The title does not fully reflect the text. The results is the creation of a model equation.
Response 4. Agreed and amended
Point 5. The conclusion is non-complaining. I recommend extending the overall model and study benefits.
Response 5. Done
Point 6. I propose to rename the title.
Response 6. Done
Point 7. Explain the “d” short cut in the figure 1
Response: Explained (d: differencing) in the caption (under figure 1)
Point 8. Add to the “MaxAE” shortcuts in table 2.
Response 8. Explained under table 2 (table caption)
Author Response File: Author Response.pdf
Reviewer 2 Report
Specific comments regarding the above mentioned paper
1. The science around the paper is good.
2. The analyses are quite okay
3. The introduction and abstract are well written.
4. The results are well stated.
1. The language of the paper needs some improvement. And this should be done by a native English Speaker.
2. The discussion should be a bit expanded to recap all major results. The inclusion of other sound results from other studies is recommended.
Response to reviewer two comments
We appreciate the reviewer for the comments given to the manuscript.
Point 1. The language of the paper needs some improvement. And this should be done by native English speaker
Response 1. As per the recommendation, we did some improvement throughout the manuscript.
Point 2. The discussion should be a bit expanded to recap all major results. The inclusion of other sound results from other studies is recommended.
Response 2. Done
Author Response File: Author Response.pdf
Reviewer 3 Report
I did put my comments into text, and here I will point out my most problematic issues:
- although you put weather/climate parameters, you didn't try to evaluate/consider soil moisture contribution, which can be very important for modeling crop growth; is it maybe because all authors are from animal sciences, and noone from crop sciences, I can't tell, crop scientist would point out soil importance
- you are trying to conclude your paper mentioning precipitation patterns, whereas you are taking into account only number of precipitations, not their pattern! For crops, rain amount is not of upmost importance, but whether rain fell down when crop needed that water (which is different from growth stage to stage).
- also, I would like to see some chart/graph depicting precipitations and temperatures for given period, as contribution from your country for "bigger picture" of global climate changes
Comments for author File: Comments.pdf
Response to reviewer 3 comments
We amended the manuscript on some of his comments. We corrected the comments given in the text and responded to those raised as problematic as follows:
Point 1. The issue related to format in the text (Page 7, Line 201 - 206)
Response 1. Corrected. (Page 9, Line 240 -256)
Point 2. In the conclusion section, precipitation pattern is raised as a problem.
Response 2. The conclusion is re-written in line with the outcome of our analysis
Point 3. Lack of data related to soil moisture content in the manuscript was put as problem by the reviewer.
Response 3. We put our response to this comment as follows:
3.1. Our study aimed to detect the climatic factors on the dry matter yield trend over a period of time. The reason why we did so, in Korea, forage crops are not dependent on supplemental irrigation where by soil moisture is a concern. Climate based cultivation of forage crops practiced in the nation. Therefore, climate factors are more important as the increase in surface temperature in the Korean Penusella is twice as rapids as the global average. Yes, the soil moisture also important in determining the crop growth and yield characteristics. But that depends too on the type of cultivation practice and which climatic zone you are found. However, we will consider the effect of soil moisture in our future works.
3.2. The reviewer gave us other possibilities (indirect way of estimating soil moisture) to estimate the soil moisture through detecting the autocorrelation of precipitation trends. We tried to estimate using ARIMA. But this is misleading in the sense that, cultivation of most forages takes place in the sandy-loam soil where by the moisture holding capacity is very low. Rather, a separate research on the effect of soil moisture content based on real-time measurement is needed.
3.2. Again, the amount of rain is very important for optimal yield of forage crops. This affects the much needed dry matter yield and other quality parameters. In the other way, climate related factors determine the forage for its digestibility, intake, or lignin content, etc…The productivity of animas also dependent on these factors.
Point 4. The reviewer tried to relate lack of soil moisture information with authors association to college of animal life sciences. Despite the college is named animal science, its staffed by team of genetics, forage agronomist, statistics specialists , ruminant nutritionists, agro-economists (related to animal resources economics), etc., So, authors in this manuscript are multidisciplinary type with specially on grassland and forage agronomy and statistics. Just to say that the knowledge about soil exists.
Author Response File: Author Response.pdf
Reviewer 3 Report
Authors presented rather convincing arguments about my greatest concern (about soil moisture impact) in their letter to me, but they didn't explain them within the paper.
So I would like to see some sentence(s):
- about showing awareness about importance of soil moisture (it can be in "Introduction")
- about efforts for evaluating soil moisture by their model (ARIMA) and failing to present significance (based on their model), thus excluding it from the model's further consideration (because, they did some estimates, and made some conclusions, as they confirmed it into their Response 3.2.!!!)
- explaining why they think that soil moisture is not of upmost importance in S.Korea (they explained well also in Response 3.2 - low water holding capacity, and in Response 3.1. - dependance of soil tillage / cultivation practices)
So, make issue of soil moisture visible (together with your arguments) to future readers, as you tried to explain to reviewer!
I am glad that you are aware of issue of soil moisture conservation enough to consider it for further work, especially because SSH has great potential as crop which can fit perfectly into conservation soil tillage strategies (does not require deep tillage, excellent soil coverage during growth, anti-weed competitor, thus very promising for no-tillage approach, etc...). I met a more than few scientists from S. Korea who are researching that topic.
Small issue: in line 497, change dot (.) into comma (,), and change "We..." into "we..."
Response to reviewer 3 (Round two)
We very much thankful to the reviewer for all his suggestions.
Even though currently we don’t have soil moisture data, based on the clue we are given, we did our best to address the issue of soil moisture in the introduction and discussion part.
In the introduction: Page 2, Line 42-45
In the discussion: Page 10, Line 308-315
All relevant references are included
Format issue… climatic factors on DMY. We recommend…
Corrected as, …climatic factors on DMY, we recommend…