Review Reports - Pre-Plant Fumigation of Soils for Nematode Control Affects the Seedling Production and Morphological Properties of Pine and Larch Seedlings

Round 1

Reviewer 1 Report

Detailed Comments:

The manuscript is logically built, and well-written. The experiments are thoroughly conducted and the results provide important information about the effect of the fumigant on the soil and the properties of two different seedlings.

Below are the more detailed comments and questions from this reviewer:

Page 2, Lines 67-77: Was the soil tilled prior to the application of Dazomet? Usually it is recommended to till the soil twice before fumigation, first ten days in advance, followed by a second tilling directly before fumigation. Was the soil temperature above 13^oC at 15-20 cm depth during the treatment? Was the area sprayed with water to moisten the soil to activate the fumigant? How far were the treated areas from the control plots? What was the buffer zone? Page 2, Line 69: Was liquid Dazomet used? Dazomet is a solid (metam sodium is a liquid). Page 3, Lines 96-100: If the nematodes were killed and fixed for enumeration, how can the authors tell which nematodes were affected by the fumigation? Page 3, Line 103: What was the length of the study, 5 months (April 15 – September 15)?

What was the concentration of the Dazomet in the soil at the end of the study?

Page 5, Line 154, Figure 2: Please provide explanation for the marker symbols with colors. Page 6, Line 171, Figure 3: The lines and numbers are faint; the numbers are small and hard to read on the plot. Page 6, Lines 188 – 197: In the Discussion, the effect of nematodes on the change in OM could be more precisely discussed if the number of nematodes that survived the fumigation, was known.

Author Response

17 September 2019

Dear Editor and Reviewers:

We would like to submit our revised manuscript, titled “Pre-plant Fumigation of Soils for Nematode Control Affects the Seedling Production and Morphological Properties of Pine and Larch seedlings.”

The manuscript has been carefully revised, and changes have been made in accordance with the reviewers’ suggestions, although a part of the comments from Reviewer 2 are guessed to be missing. We sent two replies to confirm what speculated to be missing, but we didn't get an answer, so we responded according to the given comments of Reviewer 2.

The resubmitted manuscript consists of "Revised tracked file". "Revised tracked file" is revised manuscript using the "Track Changes" function in Microsoft Word. Please see the attachment.

We thank you and the reviewers for your thoughtful suggestions and insights, which have enriched the manuscript and produced a more balanced and better account of our research. We hope that the revised manuscript is now suitable for publication in Forests.

Response to the Reviewer 1

- Comment 1: The manuscript is logically built, and well-written. The experiments are thoroughly conducted and the results provide important information about the effect of the fumigant on the soil and the properties of two different seedlings.

- Response to comment 1: Thank you for your constructive comments, which helped us to improve the manuscript. We have added information, and corrected some errors regarding the Materials and Methods with your suggestions.

- Comment 2: Page 2, Lines 67-77: Was the soil tilled prior to the application of Dazomet? Usually it is recommended to till the soil twice before fumigation, first ten days in advance, followed by a second tilling directly before fumigation. Was the soil temperature above 13oC at 15-20 cm depth during the treatment? Was the area sprayed with water to moisten the soil to activate the fumigant? How far were the treated areas from the control plots? What was the buffer zone?

- Response to comment 2: We added and corrected information of the Dazomet treatment method in Materials and Methods. We, as you comment, tilled the soil before the Dazomet treatment, irrigated the soil after the Dazomet treatment, and then tilled once again. We added the additional information to the Material and Methods (Page 2, line 76-78).

Dazomet treatment period in the manuscript was revised from 14 days to 4 months (Page 2, line 78). It is an error in the process of writing the manuscript. We performed the treatment of Dazomet for 4 months, because of the low soil temperature in winter.

The 10 m perimeter of the treatment plots is set to the buffer zone by referring to Reregistration Eligibility Decision (RED) for Dazomet (2008). Control plot was also at least 10 meter away from the treatment plots. We added this information to the Materials and Methods of the manuscript (Page 2, line 81-82).

- Comment 3: Page 2, Line 69: Was liquid Dazomet used? Dazomet is a solid (metam sodium is a liquid).

- Response to comment 3: We used granule form of Dazomet. We added this information to the manuscript (Page 2, line 76-77).

- Comment 4: Page 3, Lines 96-100: If the nematodes were killed and fixed for enumeration, how can the authors tell which nematodes were affected by the fumigation?

- Response to comment 4: We thought that dead nematode due to fumigation are not extracted because the Baerman funnel method extracts only nematodes in the active state.

- comment 5: Page 3, Line 103: What was the length of the study, 5 months (April 15 – September 15)?

- Response to comment 5: Yes, the plant growth period is about 5 months from April to September.

- Comment 6: What was the concentration of the Dazomet in the soil at the end of the study?

- Response to comment 6: After the end of study, the concentration of Dazomet was not measured. We think that there is no Dazomet remaining because we have fully proceeded the volatilization process.

- Comment 7: Page 5, Line 154, Figure 2: Please provide explanation for the marker symbols with colors.

- Response to comment 7: We repainted to improve Figure 2, and added information for the marker symbols.

- Comment 8: Page 6, Line 171, Figure 3: The lines and numbers are faint; the numbers are small and hard to read on the plot.

- Response to comment 8: We repainted to improve Figure 3.

- Comment 9: Page 6, Lines 188 – 197: In the Discussion, the effect of nematodes on the change in OM could be more precisely discussed if the number of nematodes that survived the fumigation, was known.

- Response to comment 9: The relationship between number of nematodes and changes of OM could not be more precisely discussed because linear regression analysis did not show significant. This result is speculated that the result is due to the fact that the fumigation affects not only the nematode, but also the microbes. We are believed that the elimination of nematodes by fumigation had a big impact in the change of soil OM, but it could not directly explain the role of nematodes and microbes in the change of OM. The mechanism of change of OM due to changes in nematodes and microbes caused by fumigation is the interesting part that should be addressed in further study.

Thank you very much once again for your intensive comments and suggestions.

Author Response File: Author Response.docx

Reviewer 2 Report

This research article provides information on pre-plant fumigation of soils for nematode control affects the seedling production and morphological properties of pine and larch seedlings. There is clear need for second repetition of field trial to help elucidate findings. Even though it is re-submission, substantial revision is still needed to improve the clarity of the information provided, particularly regarding the nematode species. Without knowing if the nematodes pathogenic or non-pathogenic, it is difficult to understand the results. More specific comments are provided below.

Author Response

17 September 2019

Dear Editor and Reviewers:

The resubmitted manuscript consists of "Revised tracked file". "Revised tracked file" is revised manuscript using the "Track Changes" function in Microsoft Word. Please see the attachment.

Response to the Reviewer 2

- Comment 1: This research article provides information on pre-plant fumigation of soils for nematode control affects the seedling production and morphological properties of pine and larch seedlings. There is clear need for second repetition of field trial to help elucidate findings. Even though it is re-submission, substantial revision is still needed to improve the clarity of the information provided, particularly regarding the nematode species. Without knowing if the nematodes pathogenic or non-pathogenic, it is difficult to understand the results. More specific comments are provided below.

- Response to comment 1: Thank you for your valuable comment, which helped us to improve the manuscript. Our study consists of total 56 separated experimental plots, and nursery filed where the experiment was conducted was carried out created a homogeneous state through plowing and harrowing. We believe that the results obtained under these experimental conditions are reliable.

In our study, the density of pathogenic nematodes was not provided because the identification of soil nematodes was not conducted. So we added the information of plant pathogenic nematodes and fungi by referring a report that examined the same nursery filed (Page 2, line 66-71).

Thank you very much once again for your intensive comments and suggestions.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

This reviewer would like to thank the authors for considering the review comments and adding to/modifying the manuscript narrative and the figures accordingly.

Reviewer 2 Report

The authors made the required edits and addressed the concerns in this version.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

This research article provides information on pre-plant fumigation of soils for nematode control affects the seedling production and morphological properties of pine and larch seedlings. The problem being addressed is critical to forestry and nursery production; thus, the research presented is of great importance. But, there is clear need for second repetition of field trial to help elucidate findings.Substantial revision is needed to improve the clarity of the information provided, particularly regarding the nematode species. Without knowing if the nematodes pathogenic or non-pathogenic, it is difficult to understand the results. More specific comments are provided below.

The authors need to choose keywords carefully; a few suggestions are Pinus densiflora; Larix kaempferi

Line 40- Please complete the sentence with “.”.

Line 43- What type of soil condition and changes are you pointing?

Line 47- Please re-write the sentence. What do you mean with managing the nursery?

Line 56- Please re-write.

Line 66- It is better to present minimum and maximum temperatures, total rainfall for the experiment duration.

Line 73- What did you use to cover? Color, material and thickness will be helpful.

Line 73- at 2–3-day intervals after removal of cover.

Line 76- Did you make count for the dead seedlings? What was the reason of removing dead seedlings and what is the reason of dead?

Line 125- What type of nematodes? Are those pathogenic, non-pathogenic; what species? Do you call nematode density as soil property? This needs to be re-written under another section.

Line 188- This is very weak statement and I don’t think it will be appropriate to use. Please re-write this part. When you removed the dead seedlings; how do you make this conclusion?

Line 263- Please re-write the sentence.