Weed Pressure, Nutrient Content, and Seed Yield in Field Grown Sulfonylurea-Resistant Camelina sativa and Brassica napus
Round 1
Reviewer 1 Report
Dear Editor,
I have critically gone through the complete draft. I congratulate and appreciate the efforts of Anderson et al. for drafting the manuscript in a very good manner. The overall manuscript looks in a good condition. Although, minor spell checking and grammatical errors need to be re-checked for its further processing.
Also kindly confirm the followings -
Trifluralin is a herbicide applied before sowing of the crop as pre-plant incorporation (PPI), where in lines 112-113, it is mentioned as a pre-emergence application (application after sowing of the crop but before emergence), can you please clear it?
The conclusion is too descriptive, it can be shortened.
Author Response
Reviewer # 1
Dear Editor,
I have critically gone through the complete draft. I congratulate and appreciate the efforts of Anderson et al. for drafting the manuscript in a very good manner. The overall manuscript looks in a good condition. Although, minor spell checking and grammatical errors need to be re-checked for its further processing.
Thank you for your kind words. We appreciate the time you invested in reviewing our manuscript and your very valuable suggestions to improve it.
Also kindly confirm the followings -
Trifluralin is a herbicide applied before sowing of the crop as pre-plant incorporation (PPI), where in lines 112-113, it is mentioned as a pre-emergence application (application after sowing of the crop but before emergence), can you please clear it?
Thank you for bringing this to our attention. Yes, trifluralin was a pre-planted and incorporated herbicide. The word pre-emergence is incorrect and was deleted.
The conclusion is too descriptive, it can be shortened.
We have revised the conclusions section to reduce some of the descriptive language.
Reviewer 2 Report
Abstract line 16: Mention the year.
Abstract line 20: The cultivars/varieties of the crops should be mentioned.
Abstract lines 26-28: Considering this conclusion, did you evaluate the other methods (besides the chemical method) involved in IPM?
Page 2 line 70-76: Mention the negative impacts of herbicides application on agro ecosystems as well.
Page 5 line 143: 0-25 cm is the active agronomic soil zone. Is there a reason why you considered deeper layers?
Page 5 Table 2: EC (electrical conductivity) of the soil must be taken into account as a fundamental factor.
Comments for author File: 
Comments.pdf
Author Response
Reviewer # 2
Thank you for your thoughtful suggestions.
Comments and Suggestions for Authors
Abstract line 16: Mention the year.
Year added
Abstract line 20: The cultivars/varieties of the crops should be mentioned.
The varieties are indicated in Materials and Methods section 2.1
Abstract lines 26-28: Considering this conclusion, did you evaluate the other methods (besides the chemical method) involved in IPM?
The short answer is no. There are many IPM approaches including biological, chemical, cultural, and mechanical. The results of this study show that sulfonylurea-resistant camelina and canola reduced weed pressure with or without herbicide (chemical) treatment. However, in both the abstract and the conclusions, the word “improving” was removed to reduce confusion.
Page 2 line 70-76: Mention the negative impacts of herbicides application on agro ecosystems as well.
A following was included in lines 79 – 80 “…, and the negative impacts of herbicides on agro-ecosystems,…”
Page 5 line 143: 0-25 cm is the active agronomic soil zone. Is there a reason why you considered deeper layers?
These two depths are our standard sampling protocols.
Page 5 Table 2: EC (electrical conductivity) of the soil must be considered as a fundamental factor.
EC values were added to Table 2 (early season soil samples) and mentioned in text for late season soil samples (see lines 326 – 329). In no case were the average EC values over 1.
Reviewer 3 Report
Dear Sirs,
I reviewed your manuscript entitled “Weed Pressure, Nutrient Content, and Seed Yield in Field Grown Sulfonylurea-resistant Camelina sativa and Brassica napus” (agronomy-1932225) submitted for publication on Agronomy.
I consider this manuscript a very interesting study about the effects of using ALS herbicides on 2 different crops from Brassicaceae family, camelina and canola. With these results, the crops can be more attractive to producers and their consideration to be included as a winter crop or cover crop in multi-cropping practices providing several ecosystem services The aim of this paper is to determine the performance of these crops on weed suppression, nutrient content, and yields. In general, the manuscript is well written and readable, it is well designed and executed. However, there are some minor issues that could be considered to improve the work.
Line-by-line comments:
Introduction
There is no mention to the relevance of crop nutrient content measurements, a paragraph or at least some phrases should be included in the introduction to give to the readers the background about it. As it is, there is no reason to include those data and analyze it. In the Results and Discussion session there is some information about the purpose of measure nutrient content but not in the introduction.
L80-83: I recommend the paper “Knezevic, S. Z., & Cassman, K. G. (2003). Use of herbicide‐tolerant crops as a component of an integrated weed management program. Crop Management, 2(1), 1-7” to support this sentence.
Materials and Methods
L123: What kind of weeds? It would be better to clarify, if is possible, which type of weeds you had on the plots. The list of species would be perfect, or at least the families or if they were mainly grasses or broadleaved weeds. Something that could give a better frame to understand the results. Clearly, is not the same a good weed suppression by crops on some competitive weeds than other less competitive species. Also, why did you measure stems instead of another weed characteristic? It was because most weeds were grasses, which make more difficult to identify individually in later stages?
Results
L240: At NW22 it seems there is no reduction in late season between camelina and fallow (Fig 1B).
L250-253: This is interesting. Any idea why this could happen? Any phytotoxic effect on the crop?
L291-308: What about precipitations between the sites? Could be differences in precipitations that affect the herbicide performances?
Author Response
Reviewer # 3
Comments and Suggestions for Authors
Dear Sirs,
I reviewed your manuscript entitled “Weed Pressure, Nutrient Content, and Seed Yield in Field Grown Sulfonylurea-resistant Camelina sativa and Brassica napus” (agronomy-1932225) submitted for publication on Agronomy.
I consider this manuscript a very interesting study about the effects of using ALS herbicides on 2 different crops from Brassicaceae family, camelina and canola. With these results, the crops can be more attractive to producers and their consideration to be included as a winter crop or cover crop in multi-cropping practices providing several ecosystem services The aim of this paper is to determine the performance of these crops on weed suppression, nutrient content, and yields. In general, the manuscript is well written and readable, it is well designed and executed. However, there are some minor issues that could be considered to improve the work.
Thank you for your kind words. We are thrilled you found our research very interesting. We appreciate the time you took to revise it and provide suggestions to improve our manuscript.
Line-by-line comments:
Introduction
There is no mention to the relevance of crop nutrient content measurements, a paragraph or at least some phrases should be included in the introduction to give to the readers the background about it. As it is, there is no reason to include those data and analyze it. In the Results and Discussion session there is some information about the purpose of measure nutrient content but not in the introduction.
With all due respect, Line 45 states “…and soil nutrient losses,…” Line 60 states “… nutrient retention,…” Lines 65 – 66 states “…and retained significant levels of nutrients (N, P, K, S)—similar to that retained by alfalfa.” These are all related to the ecosystem services which are associated with cover crops and mentioned within the introduction. Regardless, we have added the following text (lines 61 – 63) “The ability of these cover/cash crops to scavenge soil nutrients also helps to reduce nutrient leaching into aquatic ecosystems and the associated environmental consequences [25, 26, 57-60].”
L80-83: I recommend the paper “Knezevic, S. Z., & Cassman, K. G. (2003). Use of herbicide‐tolerant crops as a component of an integrated weed management program. Crop Management, 2(1), 1-7” to support this sentence.
Thank you for this helpful recommendation, it was included in Line 87 of Introduction.
Materials and Methods
L123: What kind of weeds? It would be better to clarify, if is possible, which type of weeds you had on the plots. The list of species would be perfect, or at least the families or if they were mainly grasses or broadleaved weeds. Something that could give a better frame to understand the results. Clearly, is not the same a good weed suppression by crops on some competitive weeds than other less competitive species. A list (Table 4) of weeds at both locations has been included in the manuscript. Also, why did you measure stems instead of another weed characteristic? We were interested in determining the impact on weed densities and biomass in this study. It was because most weeds were grasses, which make more difficult to identify individually in later stages?
Results
L240: At NW22 it seems there is no reduction in late season between camelina and fallow (Fig 1B).
Thank you for pointing this out. We have revised the sentence (lines 258 – 261) to read “Except for late-season weed stem counts at NW22 (Figure 1, B), sulfonylurea-resistant camelina alone (without herbicide treatment) significantly reduced mid- and late-season weed stem counts (Figure 1 A) and weed biomass dry weights (Figure 1, C and D) at NDSU and NW22 compared with fallow.”
L250-253: This is interesting. Any idea why this could happen? Any phytotoxic effect on the crop?
We also find this interesting, but we could only include unwarranted speculation at this point.
L291-308: What about precipitations between the sites? Could be differences in precipitations that affect the herbicide performances?
A figure (Figure S1) including daily min and max temp and precipitation was included in the supplemental files. The following text was also included in the methods section (lines 135 - 139) “Data for daily temperature and precipitation during the 2020 growing season (Figure S1) at both field sites was obtained from North Dakota Agricultural Weather Network station located in Fargo, ND https://ndawn.ndsu.nodak.edu/station-info.html?station=23). The weather station is located approximately 0.8 km south of the NDSU and 5.2 km south-east of the NW22 study sites.”
