The Effects of Irrigation, Topping, and Interrow Spacing on the Yield and Quality of Hemp (Cannabis sativa L.) Fibers in Temperate Climatic Conditions
, Vladimir Sikora 1, Mirjana Kostić 3, Aleksandra Ivanovska 4, Biljana Pejić 3 and Bojan Vojnov 2Round 1
Reviewer 1 Report
The manuscript describes the effect of irrigation, spacing and topping on quality and yield of hemp (Canabbis sativa). This is an appropriate agronomical trial which has direct relevance to application of the technology in the field, especially to the farmers. However, the manuscript needs some measure improvements as suggested below:
The author mentions that hemp is cultivated only in 350 ha in Serbia. Therefore, the economic significance of conducting a purely applied research having clientele area of 350 ha should be justified. It may be appropriate to give some projection in terms of possibility of area expansion, economic gain along with opportunity cost so that the manuscript looks more relevant.
In the materials and method section, some clarification on the layout and statistical design may be given. Three irrigation treatments and one control (I0) have been imposed along with two spacing and topping/non-topping. The plot size/experimental unit has been kept at 2.5 m2. In such a situation, how was the irrigation treatment imposed without affecting the neighbouring plots? Such experiments usually employ split plot or split split plot design. Please given the feasibility and justification of using a Randomised Complete Block Design (I believe it was a factorial RBD). Does the precision for comparison of irrigation treatment outweighs the error expected in the neighbouring plots because of lateral movement of water?
The layout of the experiment may be pictorially depicted.
The variety of hemp used in the study may be mentioned.
In line no 112, the unit of altitude (84….?) may be mentioned.
In both abstract and conclusion needs to be coherent and the outcome should be clearly spelt out. In the conclusion section, the authors have stated that “As statistically significant differences in fiber yield and quality between RS1 and RS2 were not found, the hemp growers could be recommended the first alternative if the goal is better weed control or second alternative if the goal is seed saving.” However, no evidence has been cited in the manuscript regarding the seed rate and the savings that would accrue by way of reducing the population density vis a vis weed control. Therefore, the statement in the conclusion itself is inconclusive. Moreover, there is no statistical difference between the two spacing for yield and quality of hemp. In such a scenario, it is apparent that both the spacing has equal effect on the weed control as stand density is complete/full and there is no empty space in the inter row spaces. The authors may look into the statement and place their justification accordingly.
Author Response
Reviewer 1: The manuscript describes the effect of irrigation, spacing and topping on quality and yield of hemp (Canabbis sativa). This is an appropriate agronomical trial which has direct relevance to application of the technology in the field, especially to the farmers. However, the manuscript needs some measure improvements as suggested below:
The author mentions that hemp is cultivated only in 350 ha in Serbia. Therefore, the economic significance of conducting a purely applied research having clientele area of 350 ha should be justified. It may be appropriate to give some projection in terms of possibility of area expansion, economic gain along with opportunity cost so that the manuscript looks more relevant.
Response 1: First of all, thank you for stating that research is a significant contribution to agricultural practice of particular benefit to farmers. Just to add that the obtained data are the results of hard work in the field and laboratory. Regardless of the modest areas on which hemp is grown in Vojvodina, the northern part of the Republic of Serbia, there is a growing interest in increasing acreages in the near future, because of very favorable agro-ecological conditions. Since there are no data on hemp production under irrigation in the Vojvodina region, and there are few such studies in the world the results of this research are gaining importance. The obtained results could enhance the local farmers to optimize the production of fiber hemp achieving high yields and fiber quality. Because of that we just add one more sentence which confirms the aforementioned statement. Currently, hemp cultivated for fiber production is covering an area of about 350 ha [4]. Regardless of the modest areas on which hemp is grown in Vojvodina there is a growing interest in increasing acreages in the near future, because of very favorable agro-ecological conditions and the interest of local farmers in the production of this plant.
Reviewer 1: In the materials and method section, some clarification on the layout and statistical design may be given. Three irrigation treatments and one control (I0) have been imposed along with two spacing and topping/non-topping. The plot size/experimental unit has been kept at 2.5 m2. In such a situation, how was the irrigation treatment imposed without affecting the neighboring plots? Such experiments usually employ split plot or split split plot design. Please given the feasibility and justification of using a Randomised Complete Block Design (I believe it was a factorial RBD). Does the precision for comparison of irrigation treatment outweigh the error expected in the neighboring plots because of lateral movement of water?
Response 1: As you suggested the layout of the experiment is pictorially depicted and explained (Figure 1). (The area of each individual basic plot was 7 m2 (2x3.5 m). At harvest the aboveground fresh biomass and number of plants were determined from the center of the basic plot from an area of 2.5 m2, while each side was 0.5 m away in order to avoid the effect of irrigation from neighboring plots).
Reviewer 1: The layout of the experiment may be pictorially depicted.
Response 1: Figure 1.
Reviewer 1: The variety of hemp used in the study may be mentioned.
Response 1: As for the variety of hemp used in the study it is already in the text (line 143-144), but we additionally mentioned the name of the variety in the abstract as well.
Reviewer 1: In line no 112, the unit of altitude (84….?) may be mentioned.
Response 1: In the line 112 the correction was made (m).
Reviewer 1: In both abstract and conclusion needs to be coherent and the outcome should be clearly spelt out. In the conclusion section, the authors have stated that “As statistically significant differences in fiber yield and quality between RS1 and RS2 were not found, the hemp growers could be recommended the first alternative if the goal is better weed control or second alternative if the goal is seed saving.” However, no evidence has been cited in the manuscript regarding the seed rate and the savings that would accrue by way of reducing the population density vis a vis weed control. Therefore, the statement in the conclusion itself is inconclusive. Moreover, there is no statistical difference between the two spacing for yield and quality of hemp. In such a scenario, it is apparent that both the spacing has equal effect on the weed control as stand density is complete/full and there is no empty space in the inter row spaces. The authors may look into the statement and place their justification accordingly.
Response 1: As you suggested, we made that the text in Abstract and Conclusion more coherent and understandable. It is a true that there is not any reference cited in the paper regarding the amount of seed and the savings that would be achieved by reducing the crop density for weed control, as that was not the focus of our research. Because of that the sentence “As statistically significant differences in fiber yield and quality between RS1 and RS2 were not found, the hemp growers could be recommended the first alternative if the goal is better weed control or second alternative if the goal is seed saving” is deleted as it was the most appropriate. So, in both the Abstract and the Conclusion, we only stated that inter-the row spacing did not have a statistically significant effect on hemp fiber yield and quality.
As suggested the English text was corrected by the native English speaker.
On this occasion, we would like to thank you, on behalf of all the authors of the paper, for the very useful suggestions that will certainly contribute to the quality of the paper.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
1. Arrange the following key words: hemp; irrigation; topping; row spacing; yield; fiber quality with the first letter in alphabetical order.
- Ine 45-46: revise this sentence for grammatical mistake “In Serbia, hemp is traditionally cultivated in Vojvodina, the northern part of the country, and the largest cultivated area of 20,000 ha has been recorded in 1968.”
- Line 50-52: This paragraph should be refined. Irrigation and environment are too broad to be narrowed down with an example on water stress alone. Include more relevant examples
- Lines presented under Figures 3 and 4 are too thick. To enhance legibility, reduce the thickness accordingly.
- Line 331, avoid making conclusions in the discussion. In any case how many conclusions will you make in this study?
- As part of results, present a Table with detailed summary of soil hydraulic properties.
- Also plot a graph clearly showing Water Use per crop for every irrigation interval over the entire crop development period.
Author Response
Reviewer 2: Arrange the following key words: hemp; irrigation; topping; row spacing; yield; fiber quality with the first letter in alphabetical order.
Response 2: We expected to arrange key words as you suggested (alphabetical order).
Reviewer 2: 1. Line 45-46: revise this sentence for grammatical mistake “In Serbia, hemp is traditionally cultivated in Vojvodina, the northern part of the country, and the largest cultivated area of 20,000 ha has been recorded in 1968.”
Response 2: The sentence “In the Republic of Serbia, hemp is traditionally cultivated in Vojvodina, the northern part of the country, and the largest cultivated area of 20,000 ha has been recorded in 1968.” was grammatically corrected.
Reviewer 2: 2. Line 50-52: This paragraph should be refined. Irrigation and environment are too broad to be narrowed down with an example on water stress alone. Include more relevant examples
Response 2: Line 50-52. Instead the word environment, words climate and soil conditions were used as more acceptable.
Reviewer 2: 3.Lines presented under Figures 3 and 4 are too thick. To enhance legibility, reduce the thickness accordingly.
Response 2: To enhance legibility of Figures 3 and 4 the thickness of lines was corrected as you suggested.
Reviewer 2: 4. Line 331, avoid making conclusions in the discussion. In any case how many conclusions will you make in this study?
Response 2: Line 331. To avoid making conclusions in the discussion part some words in the sentence were deleted.
Reviewer 2: 5. As part of results, present a Table with detailed summary of soil hydraulic properties.
Response 2: As you suggested water-physical and chemical properties of the soil were presented in Tables instead writing in the text.
Reviewer 2: 6. Also plot a graph clearly showing Water Use per crop for every irrigation interval over the entire crop development period.
Response 2: Regarding your suggestion to plot a graph of water use for every irrigation interval over the entire crop development period, our opinion is that it would be a duplication of data because the requested data is clearly visible in the fiber hemp water budget tables (5 and 6).
On this occasion, we would like to thank you, on behalf of all the authors of the paper, for your time and for the very useful suggestions that will certainly contribute to the quality of the paper.
Author Response File: Author Response.pdf
