Effect of Furrow Straw Mulching and Straw Decomposer Application on Celery (Apium graveolens L.) Production and Soil Improvement

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript of “Effect of furrow straw mulching and straw decomposer application on celery (Apium graveolens L.) production and soil improvement” provided the new approach for straw mulching on the furrow, and investigated its effects on celery yield, and soil properties which are beneficial for agriculture and sustainability. However, I have some questions and suggestions:

 

Introduction

1.      Lines 45-47, please provide more details on examples of environmental factors, vegetables, and yields in the facility cultivation because the conditions of facility conditions link to lines 95-96.

2.      Introduction part, please insert more specific details for the suitable conditions of growing celery such as temperature, soil moisture, N, P, K, soil ECe, also yield related to those factors.

Materials and Methods

3.      Lines 120-128, please provide a light intensity or PAR during experiments.

Discussion

4.      It would be nice, if the authors include, or compare the yield between furrow mulching, and bed mulching for celery.

5.      Lines 399-404, please discuss more specific mechanisms related to P, and K from straw mulching on Vc, total flavonoid, and total phenolic content.

6.      Lines 442-449, related to the temperature, did the author measure soil temperature? Please provide the result.

References

7.      Please change to the journal style.

 

 

Author Response

Dear reviewer, the authors are thankful for the time you spent reviewing the manuscript. The authors have tried their best to add information according to your comments. Your valuable suggestions helped us to improve our manuscript. The response to your comments has given in the attached file of response to reviewer comments.

 

Reviewer 1:

Comments

The manuscript of “Effect of furrow straw mulching and straw decomposer application on celery (Apium graveolens L.) production and soil improvement” provided the new approach for straw mulching on the furrow, and investigated its effects on celery yield, and soil properties which are beneficial for agriculture and sustainability. However, I have some questions and suggestions:

General Response:

--Dear reviewer, your positive comments encouraged us to revise the manuscript to our best. Hope the changes we have done according to your comments can make you satisfied with our revision.

 

Introduction

1. Lines 45-47, please provide more details on examples of environmental factors, vegetables, and yields in the facility cultivation because the conditions of facility conditions link to lines 95-96.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we have added detailed information on environmental factors, vegetables and yield examples in facility-based cultivation to the article.

 

According to announcements by the Chinese government and relevant departments, the area of modern facility cultivation in China has reached 2.67 million ha, and the area of facility agriculture accounts for more than 80% of the total area in the world, of which facility vegetable cultivation accounts for 81% of the area of facility cultivation in China. (https://www.gov.cn/yaowen/liebiao/202308/content_6897358.htm, accessed on September 1, 2023 ; https://www.moa.gov.cn/ztzl/2023yhwj/xcbd_29328/202303/t20230309_6422688.htm, accessed on September 1, 2023; https://www.moa.gov.cn/ztzl/ymksn/gmrbbd/202205/t20220526_6400512.htm, accessed on October 17, 2023). The survey of relevant government departments shows that in 2021, China's facility vegetable production has reached 230 million tons, accounting for 30% of the total vegetable production (https://www.gov.cn/zhengce/202307/content_6890148.htm, accessed on October 17, 2023). (Lines 39-51)

To date, these microorganisms are commonly used in field crops such as rice, wheat and corn [20,21]. However, a large number of vegetables are produced in facilities (such as plastic sheds). Due to the well insulated performance of the shed, temperatures inside the sheds are often higher than outside, and this temperature difference is more pronounced during the daylight hours [22]. In addition, the amount of irrigation inside the shed is usually much higher than outside, and the annual irrigation often exceeds 1300 mm, which leads to high temperature and high humidity climatic conditions inside the shed [23]. The activity of straw decomposing bacteria is easily affected by the environment. However, there are few studies on whether the application of straw decomposers can effectively decompose straw under high temperature and high humidity facility conditions. (Lines 93-103)

 

2. Introduction part, please insert more specific details for the suitable conditions of growing celery such as temperature, soil moisture, N, P, K, soil ECe, also yield related to those factors.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we have added suitable conditions for celery growth and provided the effect of these factors on yield.

 

Celery production has a high demand for fertilizer. Navarro et al. found that the highest celery yield (12.54 kg/m²) was achieved when N, P and K were applied at 257 kg/ha, 38 kg/ha and 475 kg/ha respectively [28]. In southern China, celery can be cultivated all year round, but it grows best at temperatures between 15 ℃ and 20 ℃ [29]. Celery also has a high water demand during growth and can be used for wet-upland rotation [30,31]. Therefore, celery was used as the cultivated crop to explore the effects of different straw amounts and different straw decomposers on the soil physicochemical properties and the celery yield and quality. We investigated if furrow straw mulching technology and straw decomposer application are feasible under intensive leafy vegetable production facilities. (Lines 119-127)

 

 

Materials and Methods

3. Lines 120-128, please provide a light intensity or PAR during experiments.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we added the photosynthetically active radiation during experiments.

 

Figure S3 The photosynthetically active radiation during experiments.

 

 

Discussion

4. It would be nice, if the authors include, or compare the yield between furrow mulching, and bed mulching for celery.

--We thank the reviewer for this suggestion.

-- Celery is an intensively cultivated leafy vegetable, and it is difficult to mulch straw on the beds in agricultural production, so we regret that we were unable to compare the yield between furrow mulching and bed mulching for celery.

 

 

5. Lines 399-404, please discuss more specific mechanisms related to P, and K from straw mulching on Vc, total flavonoid, and total phenolic content.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we added more specific mechanisms related to P, and K from straw mulching on Vc, total flavonoid, and total phenolic content.

 

The beneficial effects of straw mulching on soil improvement has been well established, including that alleviate soil salinization, reduce nitrate nitrogen leaching and increase soil organic carbon content [48-51]. Moreover, straw mulching can improve crop qualities such as Vc, flavonoids and total phenolics by increasing soil phosphorus and potassium nutrients [52]. Potassium fertilization can regulate stomatal opening and improve photosynthesis in plants, thereby increasing the activity of GalLDH, a key enzyme that catalyzes Vc synthesis, and leading to an increase in Vc synthesis in plants [53,54]. Also, it has been shown that high potassium fertilizer application increased the production of TNC (D-glucose), a precursor substance for Vc biosynthesis in plants, which leads to the production of more Vc in the L-galactose pathways [55,56]. Some studies indicated that increasing potassium supply also increases the activity of PAL (Phenylalanine-Ammonia-Lyase) in plants, which increased flavonoids and total phenolic content in plants [56]. Liu et al. found that proper application of phosphorus fertilizer enhanced the inhibition of hydroxyl radicals, superoxide anion radicals and DPPH radicals , and increased the flavonoid content of plants [57]. (Lines 421-434)

 

 

6. Lines 442-449, related to the temperature, did the author measure soil temperature? Please provide the result.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we added the soil temperature in the furrows after straw decomposer application. We also added the temperature changes in the shed during the experimental period.

 

Figure S1 Temperature variations during experiments.

 

Figure S2 Changes of the soil temperature in the 0~10 cm soil layer of furrows after different types of straw decomposer application. CK₂: no straw decomposer added. SD₁: straw decomposer "JiaLefeng", SD₂: straw decomposer "LanYue", SD₃: straw decomposer "ZhuBang". The different lowercase letters in the figure indicate significant differences between the different treatments based on the bidirectional ANOVA tests (P<0.05).

 

 

References

7. Please change to the journal style.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we have changed the citation format of the references as required by the journal.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

I read the manuscript with high interest. This work is quite actual. The manuscript is well organized and nicely written. The presented results are very important and interesting to readers. The manuscript is well illustrated and very clear.

I would like to thank you for making an important contribution to investigating such a relevant topic.

However, there are some issues to address to, before the manuscript could be accepted.

1.      Lines 59-62: Do you have more recent data?

2.      Lines 114-119: Please, divide this sentence into 2 parts. Could you, please, add a working hypothesis?

3.      Lines 122-128: could you, please, add characteristics of soil types in the studied plots?4.      Line 135: Data from table 1 – is this Your data or from literature? Need reference

5.      Line 146: Table S2

6.      Line 147: Did weather conditions have any influence during two experiments - from March 123 to July and July to November 2021?

7.      Lines 150-167: what plot had a treatment with some or other amount of mulching or different decomposers applied according to figure 1? What does mean Plot 1 and so on?8.      Why soil sampling points were only at plot 2?

9.      Lines 223-225: it is not shown or not obvious at figure S1.

10.   Lines 227 and further: it is worth comparing data from different experiments - rice and wheat straw.

11.   Lines 251-253: it is not shown or not obvious at figure 3.

12.   Line 254: “Compared with CK1, straw mulching significantly increased the organic carbon content in both soil layers” - it is not obvious for 10-20 cm.

13.   Line 256-257: “Nitrate nitrogen content in 10~20 cm of the beds was higher than that in 0~10 cm” - it is not obvious according to figure 3.

14.   Lines 260-261: except for Ptotal for 10-20 cm.

15.   Line 289: please decode an acronym Vc

16.   Lines 314-316: it is not obvious for wheat straw experiment.

17.   Lines 319-321: it is not significant according to figure 5.

18.   Lines 359-362: it is not significant according to figure 7.

19.   Results part: it is lack of data analysis about differences of experiments with rice and wheat straw, and experiments with different amount of mulching.

20.   Lines 364-365: why do You think the total P content of SD1 treatment increase in rice experiment?

21.   Lines 375-377: why do You think the total flavonoid content of SD1 treatment decrease in wheat experiment?

22.   Line 398: According to Your data straw mulching did not reduce nitrate nitrogen

23.   Line 402: What enzyme activities did You analyze?

24.   Lines 423-424: need a reference.

25.   Lines 454-456: it is quite interesting to define the amount of straw mulching that will not have a positive effect in order to detect the optimal range.

26.   References: Please, make a reference list according to rules. Please, add DOI where possible.

27.   Lines 543-545: these reference is not cited in the text.

28.   Table S2: what does 1^st column mean?

29.   Table S1. Please, add what does different lowercase letters mean.

Author Response

Dear reviewer, the authors are thankful for the time you spent reviewing the manuscript. The authors have tried their best to add information according to your comments. Your valuable suggestions helped us to improve our manuscript. The response to your comments has given in the attached file of response to reviewer comments.

 

Reviewer 2:

Comments

I read the manuscript with high interest. This work is quite actual. The manuscript is well organized and nicely written. The presented results are very important and interesting to readers. The manuscript is well illustrated and very clear.

I would like to thank you for making an important contribution to investigating such a relevant topic.

However, there are some issues to address to, before the manuscript could be accepted.

General Response:

--Dear reviewer, your positive comments encouraged us to revise the manuscript to our best. Hope the changes we have done according to your comments can make you satisfied with our revision.

 

1. Lines 59-62: Do you have more recent data?

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we cited new references and updated the data.

 

China produces 1 billion tons of straw annually, about 30% of the world's total straw production [4]. According to the statistics of relevant departments of the Chinese government, the comprehensive utilization rate of straw in China is 88.1% in 2021, including returning straw to fields and using it as feed and substrate for edible fungi cultivation [5,6]. (Lines 64-68)

 

 

2. Lines 114-119: Please, divide this sentence into 2 parts. Could you, please, add a working hypothesis?
3. Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we divided this sentence into 2 parts and added a working hypothesis.

 

Therefore, celery was used as the cultivated crop to explore the effects of different straw amounts and different straw decomposers on the soil physicochemical properties and the celery yield and quality. We investigated if furrow straw mulching technology and straw decomposer application are feasible under intensive leafy vegetable production facilities. (Lines 123-127)

 

 

3. Lines 122-128: could you, please, add characteristics of soil types in the studied plots?

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we added a new table S1.

 

Table S1 Characteristics of soil types before treatments (0-20cm soil layer)

	March to July	July to November
Clay (%)	23.1±0.4a	22.5±0.6a
Loam (%)	57.4±0.5a	57.8±0.3a
Sand (%)	19.5±0.4a	19.8±0.6a
pH	6.6±0.1a	6.6±0.1a

Note. Data are mean ± SD. Different lowercase letters in a row indicate significant differences (P < 0.05) between the nutrient contents of different straws.

 

 

4. Line 135: Data from table 1 – is this Your data or from literature? Need reference

-- The data were measured by us.

 

 

5. Line 146: Table S2

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we corrected the serial number of the table.

 

 

6. Line 147: Did weather conditions have any influence during two experiments - from March 123 to July and July to November 2021?

Response:

-- Our experiments were conducted at the facilities and the weather conditions did not affect the experiments.

 

 

7. Lines 150-167: what plot had a treatment with some or other amount of mulching or different decomposers applied according to figure 1? What does mean Plot 1 and so on?Good luck

Response:

-- Our experiments were conducted in a randomized block design. Plot1, Plot2, Plot3, and Plot4 represent the four treatments (CK₁/S₇₅₀₀/S₁₁₂₅₀/S₁₅₀₀₀ or CK₂/SD₁/SD₂/SD₃.) within each shed, and these treatments were randomly placed in Plot1, Plot2, Plot3, and Plot4. To make it easier for the reader to understand, we have added a textual description below Figure 1.

 

 

8. Why soil sampling points were only at plot 2?

Response:

-- We sampled the soil in each furrow and bed, and the sampling points in Figure 1 are just examples. To make it easier for the reader to understand, we have added a textual description below Figure 1.

 

 

9. Lines 223-225: it is not shown or not obvious at figure S1.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we rephrased the sentence.

 

With the increase of straw amount, the decomposition rate gradually decreased, but after 4 months of decomposition, the S₁₅₀₀₀ treatment (rice straw mulching), which had the lowest decomposition rate, also had a decomposition rate of 64.8%. (Lines 230-233)

 

 

10. Lines 227 and further: it is worth comparing data from different experiments - rice and wheat straw.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we added Tables S4 and S5 and compared the data for rice straw mulching with wheat straw mulching in the manuscript.

 

 

 

11. Lines 223-225: it is not shown or not obvious at figure S1.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we removed the incorrect description from the manuscript.

 

 

12. Line 254: “Compared with CK1, straw mulching significantly increased the organic carbon content in both soil layers” - it is not obvious for 10-20 cm.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we corrected the misdescription from the manuscript.

 

Compared with CK1, straw mulching significantly increased the organic carbon content in 0~10 cm of the beds, and different amounts of straw mulching had no significant effect on the organic carbon content in 10~20 cm of the beds (Figure 3b, Figure 3j). (Lines 264-266)

 

 

13. Line 256-257: “Nitrate nitrogen content in 10~20 cm of the beds was higher than that in 0~10 cm” - it is not obvious according to figure 3.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we removed the incorrect description from the manuscript.

 

 

14. Lines 260-261: except for Ptotal for 10-20 cm.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we corrected the misdescription from the manuscript.

 

Phosphorus and potassium nutrient contents in 0~10 cm decreased significantly and phosphorus and potassium nutrient contents in 10~20 cm decreased significantly except for total phosphorus compared with the pre-planting stage. (Lines 269-272)

 

 

15. Line 289: please decode an acronym Vc

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we added the full name of Vc (Vitamin C) to the manuscript.

 

The results showed that compared with rice straw mulching, wheat straw mulching was more effective in improving the dietary fiber, Vc (Vitamin C), flavonoid and total phenolic contents of celery (Table S4). (Lines 300-302)

 

 

16. Lines 314-316: it is not obvious for wheat straw experiment.(修订版346-347行)

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we revised the formulation.

 

The organic carbon content of 0~10 cm of the furrows was significantly increased after celery planting. Compared with CK₂, SD₂ and SD₃ treatments significantly increased soil organic carbon content (Figure 5b). (Lines 328-330)

 

Figure 5 Changes of soil conductivity, total organic carbon, total nitrogen, nitrate nitrogen, total phosphorus, available phosphorus, total potassium, available potassium in the 0~10 cm soil layer of furrows after different types of straw decomposer application. CK₂: no straw decomposer added. SD₁: straw decomposer "JiaLefeng", SD₂: straw decomposer "LanYue", SD₃: straw decomposer "ZhuBang". The different lowercase letters in the figure indicate significant differences between the different treatments based on the bidirectional  ANOVA tests (P<0.05).

 

 

17. Lines 319-321: it is not significant according to figure 5.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we corrected the misdescription from the manuscript.

 

Compared with CK₂, the total and available phosphorus contents were significantly increased in SD₃ treatment (Figure 5e, Figure 5f). (Lines 334-335)

 

 

18. Lines 359-362: it is not significant according to figure 7.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we corrected the misdescription from the manuscript.

 

SD₃ treatment showed the highest increase in celery yield compared with CK₂ (Figure 7a). Compared with CK₂, mulching rice straw significantly increased the total nitrogen content of celery in SD₃ treatment and mulching wheat straw significantly increased the total nitrogen content of celery in SD₂ and SD₃ treatments (Figure 7b). (Lines 381-385)

 

 

19. Results part: it is lack of data analysis about differences of experiments with rice and wheat straw, and experiments with different amount of mulching.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we added new Tables S4 and S5, and revised the results part of the manuscript to add data analysis for experiments with rice and wheat straw and experiments with different amount of mulching.

 

 

20. Lines 364-365: why do You think the total P content of SD1 treatment increase in rice experiment?

Response:

--We thank the reviewer for this suggestion.

--We reviewed a large amount of literature, but did not find any mechanism related to the increase of total phosphorus content by SD₁ treatment in rice experiment. The question you raised is very valuable and we will research and find the related mechanism in our next research program.

 

 

21. Lines 375-377: why do You think the total flavonoid content of SD1 treatment decrease in wheat experiment?

Response:

--We thank the reviewer for this suggestion.

--We reviewed some literature, but there are few studies on the effects of applying straw decomposers on the flavonoid content of crops, and the related mechanisms are still unknown. Thank you for your valuable suggestion, we will research and find the related mechanism in our next research program.

 

 

22. Line 398: According to Your data straw mulching did not reduce nitrate nitrogen

Response:

--We thank the reviewer for this suggestion.

-- In our study, straw mulching significantly reduced soil nitrate nitrogen. (Figure 2d, Figure 3d, Figure 3l)

 

Figure 2 Changes of soil conductivity, total organic carbon, total nitrogen, nitrate nitrogen, total phosphorus, available phosphorus, total potassium, available potassium in the 0~10 cm layer of furrows after different amounts of straw mulching.  CK₁: no mulching straw, S₇₅₀₀: mulching straw amount 7500 kg/ha, S₁₁₂₅₀: mulching straw amount 11250 kg/ha, S₁₅₀₀₀: mulching straw amount 15000 kg/ha. The different lowercase letters in the figure indicate significant differences between the different treatments based on the bidirectional  ANOVA tests (P<0.05).

 

Figure 3 Changes of soil conductivity, total organic carbon, total nitrogen, nitrate nitrogen, total phosphorus, available phosphorus, total potassium, available potassium in the 0~10 cm and 10~20 cm layer of beds after different amounts of straw mulching. CK₁: no mulching straw, S₇₅₀₀: mulching straw amount 7500 kg/ha, S₁₁₂₅₀: mulching straw amount 11250 kg/ha, S₁₅₀₀₀: mulching straw amount 15000 kg/ha. The different lowercase letters in the figure indicate significant differences between the different treatments based on the bidirectional  ANOVA tests (P<0.05).

 

 

23. Line 402: What enzyme activities did You analyze?

Response:

--We did not measure soil enzyme activity, and we revised the discussion section of the manuscript.

--Thank you for your suggestion, in the later study, we consider measuring soil enzyme activity indexes to study the effect of soil enzyme activity on celery quality.

 

The beneficial effects of straw mulching on soil improvement has been well established, including that alleviate soil salinization, reduce nitrate nitrogen leaching and increase soil organic carbon content[51-54]. Moreover, straw mulching can improve crop qualities such as Vc, flavonoids and total phenolics by increasing soil phosphorus and potassium nutrients [55]. Potassium fertilization can regulate stomatal opening and improve photosynthesis in plants, thereby increasing the activity of GalLDH, a key enzyme that catalyzes Vc synthesis, and leading to an increase in Vc synthesis in plants [56,57]. Also, it has been shown that high potassium fertilizer application increases the production of TNC (D-glucose), a precursor substance for Vc biosynthesis in plants, which leads to the production of more Vc in the L-galactose pathways [58,59]. Some studies indicated that increasing potassium supply also increases the activity of PAL (Phenylalanine-Ammonia-Lyase) in plants, which increases flavonoids and total phenolic content in plants  [59]. Liu et al. found that proper application of phosphorus fertilizer enhanced the inhibition of hydroxyl radicals, superoxide anion radicals and DPPH radicals, and increased the flavonoid content of plants [60]. (Lines 438-451)

 

 

24. Lines 423-424: need a reference.

Response:

--We thank the reviewer for this suggestion.

-- In our experiments, furrow straw mulching affected both soil properties and celery growth in the beds, which indicates the ability of straw nutrients to move laterally. In this study, the width of the beds was 1.2 m, so theoretically the nutrients from the furrows on each side of the beds would need to move laterally at least 0.6 m each to affect the whole bed.

 

25. Lines 454-456: it is quite interesting to define the amount of straw mulching that will not have a positive effect in order to detect the optimal range.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we revised this paragraph and refined our next research plan.

 

In this study, the maximum amount of straw application is 15,000 kg/ha and we found that the optimal effects of straw mulching was realized at this amount. Thus, we have reason to speculate that more straw application may result in better effects. However, the common furrow depth was about 10 cm for leafy vegetable growth, and the maximum amount of straw that could be mulched in the furrow was 15,000 kg/ha. In subsequent studies, we will try to deepen the furrows to further increase the amount of straw mulching to explore whether it can produce better results and then define the amount of straw mulching that will not have a positive effect in order to detect the optimal range. (Lines 479-486)

 

 

 

26. References: Please, make a reference list according to rules. Please, add DOI where possible.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we reformatted the references in the manuscript as requested and added the DOI number.

 

 

27. Lines 543-545: these reference is not cited in the text.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we cited the relevant literature in line 193 of the manuscript.

 

 

28. Table S2: what does 1^st column mean?

Response:

--The first column of the table indicates the time of fertilizer application.

--As suggested by the reviewer, we revised the contents of the first column of the table.

 

Table S3 Fertilization amount and schedule for celery (kg·ha^-1)

Fertilization time	CH4N2O	Ca(H2PO4)2	K2SO4
15-Mar	244.57	937.5	225
15-Apr	300	/	/
15-Jun	300	/	/
15-Jul	244.57	937.5	225
15-Aug	300	/	/
15-Oct	300	/	/

 

 

29. Table S1. Please, add what does different lowercase letters mean.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we added the meaning of lowercase letters.

 

Table S2 Nutrient contents of dry straw (mg·g^-1)

	Rice straw	Wheat straw
Total nitrogen	6.2±0.23b	8.43±0.18a
Total phosphorus	1.6±0.14b	2.71±0.11a
Total potassium	12.3±1.31b	20.64±0.85a
Organic carbon	456.02±31.73a	379.71±23.64b
Cellulose	402.5±24.63a	369.45±21.42b
Hemicellulose	227.4±15.77b	342.67±19.63a
Lignin	97.2±8.28a	67.85±4.58b

Note. Data are mean ± SD. Different lowercase letters in a row indicate significant differences (P < 0.05) between the nutrient contents of different straws.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

please find attached a file with my comments on the article

Regards

Comments for author File: Comments.pdf

Comments on the Quality of English Language

The grammatical and language mistakes noted (see attached file) should be corrected

Author Response

Dear reviewer, the authors are thankful for the time you spent reviewing the manuscript. The authors have tried their best to add information according to your comments. Your valuable suggestions helped us to improve our manuscript. The response to your comments has given in the attached file of response to reviewer comments.

 

Reviewer 3:

Comments

this manuscript brings some ideas to improving vegetable cultivation. However, there are many issues that can be immediately addressed to improve the overall communication of your work:

General Response:

--Dear reviewer, your positive comments encouraged us to revise the manuscript to our best. Hope the changes we have done according to your comments can make you satisfied with our revision.

 

1. The peer-reviewed manuscript does not meet the editorial requirements and needs a significant number of improvements. Please correct the article in accordance with the editing requirements (https://www.mdpi.com/journal/agronomy/instructions): abstract is too long; specify the type of article; the numbering of references in the text; improve the numbering of figures (figures 2,3 and 4 indicated before (line 127) than figure 1 (line 151), supplementary materials should be listed and described, etc…

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we corrected the article the article in accordance with the editing requirements. We revised the abstract and added the article type to the first line of the word version, the numbering of the figures was adjusted, and the supplementary materials were listed.

 

Abstract: Straw mulching on the wet beds is an effective method to alleviate continuous cropping obstacle in the greenhouse. However, this technique can not be applied in the production of leafy vegetables with high planting density. Straw mulching in the furrows is an alternative method in this occasion. In this study, celery (Apium graveolens L.), a vegetable prefers high planting density and wet soil was used to test the furrow straw mulching technology and the effect of different straw amounts and straw decomposers on soil improvement and celery production were investigated. The results showed that straw mulching in the furrows significantly reduced soil conductivity and nitrate nitrogen level, increased the contents of soil organic carbon and phosphorus and potassium nutrients in the bed, and then improved celery yield and quality, indicating significant lateral movement of released nutrients between furrow and bed. The positive effects of 15000 kg/ha straw application were more pronounced than those of 7500 kg/ha and 11250 kg/ha. In addition, straw decomposers accelerated the nutrient release and improved celery yield and quality. A decomposer "ZhuBang" containing Bacillus licheniformis had the most effective effect. We concluded that furrow straw mulching combined with the straw decomposer application is an effective measure for the sustainable production of leafy vegetables in intensive vegetable production facilities. (Lines 21-36)

 

 

2. If possible, please add the total nitrogen content of the soil at each stage of the experiment. Giving only the nitrate nitrogen content is not justified. Mulching with straw significantly affects the C/N ratio in soils and consequently the quality of the yield.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we added soil total nitrogen data to the figures.

 

Figure 2 Changes of soil conductivity, total organic carbon, total nitrogen, nitrate nitrogen, total phosphorus, available phosphorus, total potassium, available potassium in the 0~10 cm layer of furrows after different amounts of straw mulching.  CK₁: no mulching straw, S₇₅₀₀: mulching straw amount 7500 kg/ha, S₁₁₂₅₀: mulching straw amount 11250 kg/ha, S₁₅₀₀₀: mulching straw amount 15000 kg/ha. The different lowercase letters in the figure indicate significant differences between the different treatments based on the bidirectional  ANOVA tests (P<0.05).

 

Figure 3 Changes of soil conductivity, total organic carbon, total nitrogen, nitrate nitrogen, total phosphorus, available phosphorus, total potassium, available potassium in the 0~10 cm and 10~20 cm layer of beds after different amounts of straw mulching. CK₁: no mulching straw, S₇₅₀₀: mulching straw amount 7500 kg/ha, S₁₁₂₅₀: mulching straw amount 11250 kg/ha, S₁₅₀₀₀: mulching straw amount 15000 kg/ha. The different lowercase letters in the figure indicate significant differences between the different treatments based on the bidirectional  ANOVA tests (P<0.05).

 

Figure 5 Changes of soil conductivity, total organic carbon, total nitrogen, nitrate nitrogen, total phosphorus, available phosphorus, total potassium, available potassium in the 0~10 cm soil layer of furrows after different types of straw decomposer application. CK₂: no straw decomposer added. SD₁: straw decomposer "JiaLefeng", SD₂: straw decomposer "LanYue", SD₃: straw decomposer "ZhuBang". The different lowercase letters in the figure indicate significant differences between the different treatments based on the bidirectional  ANOVA tests (P<0.05).

 

Figure 6 Changes of soil conductivity, total organic carbon, total nitrogen, nitrate nitrogen, total phosphorus, available phosphorus, total potassium, available potassium in the 0~10 cm layer and the 10~20 cm layer of beds after different types of straw decomposer application. CK₂: no straw decomposer added. SD₁: straw decomposer "JiaLefeng", SD₂: straw decomposer "LanYue", SD₃: straw decomposer "ZhuBang". The different lowercase letters in the figure indicate significant differences between the different treatments based on the bidirectional  ANOVA tests (P<0.05).

 

 

3. When analysing changes, you should not use "... by XX to YY " (lines 230, 233, 234, 307 etc.) as the correct form is "from XX to YY".... check the whole text and correct it.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we have checked the whole text and corrected it.

 

 

4. Major mistake in Table S1. The total organic carbon in the straw is 45.1 and 37.97 mg/g and the cellulose content is 402.5 and 396.45 mg/g respectively. Either something has been miscalculated or wrongly recorded in the table, as these results are incorrect. Please check and improve.

--We thank the reviewer for this suggestion.

-- As suggested by the reviewer, we rechecked the formula and corrected the incorrect result.

 

Table S2 Nutrient contents of dry straw (mg·g^-1)

	Rice straw	Wheat straw
Total nitrogen	6.2±0.23b	8.43±0.18a
Total phosphorus	1.6±0.14b	2.71±0.11a
Total potassium	12.3±1.31b	20.64±0.85a
Organic carbon	456.02±31.73a	379.71±23.64b
Cellulose	402.5±24.63a	369.45±21.42b
Hemicellulose	227.4±15.77b	342.67±19.63a
Lignin	97.2±8.28a	67.85±4.58b

Note. Data are mean ± SD. Different lowercase letters in a row indicate significant differences (P < 0.05) between the nutrient contents of different straws.

 

 

5. If you speculate that the positive yield-forming effect depends on high straw rates (lines451-453), then conclusion 2 makes no substantive sense. A speculation about the resultsobtained should not be the same as a conclusion. Please rephrase or delete this conclusion.

Response:

--We thank the reviewer for this suggestion.

--As suggested by the reviewer, we rephrased this conclusion.

Straw mulching in the furrows significantly reduced the conductivity and nitrate nitrogen level of the soil in the beds and the furrows, promoted the accumulation of organic carbon and phosphorus and potassium nutrients, and then improved the yield and quality of celery. In this study, the best improvement in celery yield, quality and soil properties were achieved at 15000 kg/ha of straw mulching in the range of 0 to 15000 kg/ha. In addition, the application of straw decomposers can significantly increase the rate of straw decomposition, accelerate the release of nutrients from straw to the soil, and improve the yield and quality of celery in facility vegetable cultivation. The study indicated that straw decomposer "ZhuBang" containing Bacillus licheniformis is the most suitable for the application in facility vegetable cultivation. The results of the study indicated that straw mulching in the furrows and the application of straw decomposers are reasonable measures for the sustainable development of the leafy vegetable industry. (Lines 488-499)

 

Overall, the work is interesting, but due to linguistic, factual and editorial mistakes, the major

revision is required.

Good luck

Response:

-- Thank you very much for reviewing and revising our manuscript. Your effort and time spent on our manuscript are greatly appreciated by all of us. Hope the changes we have done according to your comments can make you satisfied with our revision.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

The text has been revised according to my instructions. On the other hand, I do not know why the corrected version was not made in the template file, because now the text is not adapted to the requirements of Agronomy (font, size, spacing, etc.). Moreover the names of the journals have been misspelled in the literature list (no. 14, 22, 30, 33 etc) while according to the guidelines, journals should be abbreviated and italicised. Please correct this.