Integrated Application of Inorganic and Organic Fertilizer Enhances Soil Organo-Mineral Associations and Nutrients in Tea Garden Soil
Round 1
Reviewer 1 Report
Due to the poor resolution of all the figures, it is not possible to objectively review this manuscript. Please correct the figures and send the manuscript for review one more time.
Author Response
Dear reviewer:
I am very grateful to your comments for the manuscript. According with your advice, we revised in manuscript. Some of your questions were answered below.
Point 1: Due to the poor resolution of all the figures, it is not possible to objectively review this manuscript. Please correct the figures and send the manuscript for review one more time.
Response 1: Thank you so much for your suggestion. We do improve the resolution of all the figures and present them in the revised manuscript.
Thank you and all the reviewers for the kind advice.
Sincerely yours,
Huan Li
Author Response File: 
Author Response.docx
Reviewer 2 Report
Fertilization determines the size of the yield of arable crops. It also has a significant impact on the quality of crops and the environment. Therefore, the research topic undertaken by the authors is very important.
However, in my opinion the paper should be improved to be published in the journal.
Chapter: Abstrakt and Introduction
Lines 19, 42: You use abbreviations in the text. The first time you use them, you should explain what they mean.
Lines 42-43: Explain, what fertilization you write about.
Chapter: Metods
Lines 89: Use kg hm-2 instead of kg/hm2
Sectio 2.1.
Lines 79-80: Why before starting the research, the soil was screened through a sieve with a mesh diameter of 5 mm?
Explain:
Was organic fertilizer part of the total nutrients fertilizers?
How was the dose NPK and OM100 fertilisation determined?
Which organic fertiliser was used?
How was organic fertilisation carried out?
How long after fertilisation were soil samples taken?
Were the pots watered?
What was the temperature of the soil at the time of the experiment?
Chapter: Results
In addition to the control (CK), 5 fertilisation levels were applied: NPK, OM30...OM100. It is not understood why only CK and OM70 (sectio 3.2.) and NPK and OM70 (sectio 3.3) are analysed.
Sectio 3.2.
Lines 169-170 and 179, 184: Table S1?
The figures 4 and 5 are not very legible.
Sectio 3.5.
Lines 259-260: TN content did not increase with increasing organic fertilizer dose. The amount of TN was less on OM100 than on OM70.
Lines 261: You use the word "Usually" and citation only reference 21.
Table 3. High variability (standard error) in AP content on the combination of OM30 and OM100 compared to other combinations.What influenced it?
Sectio 3.6.
Lines 270-288: Improper description of results. Revise the description.
Author Response
Response to Reviewer 2 Comments
Dear reviewer:
I am very grateful to your comments for the manuscript. According with your advice, we amended the relevant part in manuscript. Some of your questions were answered below.
Point 1: Chapter: Abstract and Introduction
Lines 19, 42: You use abbreviations in the text. The first time you use them, you should explain what they mean.
Response 1: Thank you so much for your suggestion. We supply the explanation of abbreviations in Lines 19, 42 which were presented in the Methods section 2.3 previously.
Point 2: Lines 42-43: Explain, what fertilization you write about.
Response 2: This sentence refers to the paper “Effect of organic substitution rates on soil quality and fungal community composition in a tea plantation with long-term fertilization”. Ji et al. express the applied fertilizers information as below: Urea, calcium superphosphate, and potassium sulfate were applied as synthetic N, P, and K fertilizers, respectively. The applied organic fertilizer was pig manure. They found that tea yields were all higher under fertilization during both spring and autumn seasons compared with CK.
Point 3: Section 2.1.
Lines 79-80: Why before starting the research, the soil was screened through a sieve with a mesh diameter of 5 mm?
Response 3: We did the pot experiment refer to the methods Yu et al mentioned in reference 44 which address soil preparation prior to the microcosm experiment and further analysis as “soils were air-dried and ground to pass through a 5.0-mm sieve”. I think this step was aimed to remove stones, roots and plant residues and to disrupt large soil aggregates.
Point 4: Explain:
- Was organic fertilizer part of the total nutrients fertilizers?
- How was the dose NPK and OM100 fertilisation determined?
- Which organic fertiliser was used?
- How was organic fertilisation carried out?
- How long after fertilisation were soil samples taken?
- Were the pots watered?
- What was the temperature of the soil at the time of the experiment?
Response 4: The answer to the question is as below:
- Yes, organic fertilizer is part of the total nutrients fertilizers.
- The N application rates in this study were 350 kg ha−1 as we mentioned in line 82. Organic substitution was calculated according to N rate. Except for the control treatment (CK, without N addition), the rest of the treatments were applied as follows: pure synthetic fertilization (NPK, without any organic fertilization), 30% N substituted with organic fertilizer (OM30), 50% N substituted with organic fertilizer (OM50), 70% N substituted with organic fertilizer (OM70), and 100% N substituted with organic fertilizer addition (OM100).
- The applied organic fertilizer (N 2.0 %, P2O52 %, K2O 1.8 %, organic matter 25 % and functional microorganisms 2 × 107 g−1)) was produced by Jiangyin Pengyao Lianye Bioscience & Biotechnology Co.,Ltd., in Jiangyin City, Jiangsu Province ,China.
- The organic fertilizer was mixed thoroughly with 10 kg soil separately, and then put into a PVC pot.
- The soil sampling for this study was performed two years after the pot cultivation experiment was conducted.
- The soil moisture was kept at 70% field water holding capacity by adding deionized water daily.
- All the tea plants were grown at natural temperature and photoperiod of the green house, no additional thermal source and light were supplied.
Point 5: Chapter: Results
In addition to the control (CK), 5 fertilisation levels were applied: NPK, OM30...OM100. It is not understood why only CK and OM70 (section 3.2.) and NPK and OM70 (section 3.3) are analysed.
Response 5: We did fully analyse the correlation between organic functional groups and minerals in soil aggregates as affected by different fertilizer treatments and found that there were obviously difference among CK, NPK and OM70 treatments. That is the reason why we show these results in figure3-4. The correlation analysis between organic functional groups and minerals of all treatments were provided in Supplementary Data S1 last version and Table 3 now.
Point 6: Section 3.2.
Lines 169-170 and 179, 184: Table S1?
The figures 4 and 5 are not very legible.
Response 6: Table S1 was provided in Supplementary Data S1 before. We move this data to table3 now and improve resolution of the figures 4 and 5.
Point 7: Section 3.5.
Lines 259-260: TN content did not increase with increasing organic fertilizer dose. The amount of TN was less on OM100 than on OM70.
Response 7: Thank you so much for your suggestion. We did revise the expression to “In organic and inorganic fertilized soils (OM30, OM50 and OM70), TN content was significantly increased with increasing organic fertilizer input.”
Point 8: Lines 261: You use the word "Usually" and citation only reference 21.
Response 8: This result was also supported by reference 15,16 and 20. The missing reference has been added into the revised manuscript.
Point 9: Table 3. High variability (standard error) in AP content on the combination of OM30 and OM100 compared to other combinations. What influenced it?
Response 9: This is a good question. Reviewer mentioned that study occurred high variability (standard error) in AP content on the combination of OM30 and OM100 compared to other combinations, which is quite correct! We did double check the original raw data and find that there is no problem among the contents of total carbon, nitrogen and available K, so the soil samples were out of the question. The soil we used in this paper were cultivated in the pot for two years. Then we compare the data between the 2-year cultivated soil and 3-year cultivated soil. The same phenomenon occurs. There is also high variability in AP content of OM30 and OM100 in 2-year cultivated soil. We will continue the pot experiments and explore the effect of fertilizer on AP content of soil.
Point 10: Section 3.6.
Lines 270-288: Improper description of results. Revise the description.
Response 10: Thank you so much for your suggestion. The grammatical or typographical errors have been revised.
Thank you and all the reviewers for the kind advice.
Sincerely yours,
Huan Li
Author Response File: Author Response.docx
Reviewer 3 Report
Tea is an economically important crop in China. It is therefore necessary to make technologies available at low cost and more accessible to local producers. In this case, the results of the present work show that the management of soil organic matter is of fundamental importance to reduce the use of chemical fertilizers, as well as in soil organo-mineral interactions. However, some results obtained need to be further discussed. Mainly in the discussion section the results need to be discussed in more detail.
Specific comments:
Abstract
Line 19 to 21 - This statement is not true (see line 249 to 250 in results). Treatment with organic fertilization (OM70) significantly increased soil pH, TN, AP, Ca and Mg in the soil when compared to treatment with inorganic fertilization (NPK). However, there was no significant difference when compared to no fertilization (CK). This sentence must be corrected.
Methods
In item 2.1. Pot Experiment and Fertilizer Treatments - Inform which form of organic fertilizer was used.
Discussion
Line 249 to 250 - I think the main discussion here is trying to explain why the pH of the organic and inorganic fertilization treatments are lower than the no fertilization (CK) treatment, as well as the high concentrations of TN and AP in this treatment.
Line 350 to 351 - "Treatments containing more than 50% organic fertilizer, on the other hand, enhanced soil pH". Improved the pH of the soil in relation to what? Improve explanation.
Line 354 to 355 - "The addition of organic matter such as the pig manure can help in neutralizing the soil's acidity" [add a reference]
As production data are not available, it would be interesting to compare the soil fertility data in the different treatments, if they are adequate for the tea culture, in relation to other studies.
Author Response
Response to Reviewer 3 Comments
Dear reviewer:
I am very grateful to your comments for the manuscript. According with your advice, we amended the relevant part in manuscript. Some of your questions were answered below.
Point 1: Abstract
Line 19 to 21 - This statement is not true (see line 249 to 250 in results). Treatment with organic fertilization (OM70) significantly increased soil pH, TN, AP, Ca and Mg in the soil when compared to treatment with inorganic fertilization (NPK). However, there was no significant difference when compared to no fertilization (CK). This sentence must be corrected.
Response 1: Thank you so much for your suggestion. The soil pH of fertilized treatments (NPK and OM) was obviously lower than unfertilized treatment (CK) (table 4). In fertilized soil, the organic replacement higher than 50%, specifically OM70, and OM100, had notably higher pH values than NPK, OM30 and OM50. We did correct this sentence (Line 19 to 21) by split the expression of pH and other index in the revised manuscript.
Point 2: Methods
In item 2.1. Pot Experiment and Fertilizer Treatments - Inform which form of organic fertilizer was used.
Response 2: The missing information has been added into the revised manuscript (Line 89 to 93). The applied organic fertilizer (N 2.0 %, P2O5 2.2 %, K2O 1.8 %, organic matter 25 % and functional microorganisms 2 × 107 g−1)) was produced by Jiangyin Pengyao Lianye Bioscience & Biotechnology Co.,Ltd., in Jiangyin City, Jiangsu Province ,China. The organic fertilizer was mixed thoroughly with 10 kg soil separately, and then put into a PVC pot.
Point 3: Discussion
- Line 249 to 250 - I think the main discussion here is trying to explain why the pH of the organic and inorganic fertilization treatments are lower than the no fertilization (CK) treatment, as well as the high concentrations of TN and AP in this treatment.
- Line 350 to 351 - "Treatments containing more than 50% organic fertilizer, on the other hand, enhanced soil pH". Improved the pH of the soil in relation to what? Improve explanation.
- Line 354 to 355 - "The addition of organic matter such as the pig manure can help in neutralizing the soil's acidity" [add a reference]
Response 3:
- Thank you so much for your suggestion. We did correct the expression error throughout this section.
- According to table 4 and reference 21, compared with CK, NPK and OM30 treatments significantly decreased the soil pH, while treatments with added more than 50% organic matter increased the soil pH, which indicated that adding organic matter could mitigate the soil acidification caused by chemical NPK fertilizer addition and tea planting.
- Thank you so much for your suggestion. This sentence referred to reference 21 and 31.
Point 4: As production data are not available, it would be interesting to compare the soil fertility data in the different treatments, if they are adequate for the tea culture, in relation to other studies.
Response 4: Thank you so much for your suggestion. Reviewer mentioned that study lacks the production data for the tea culture, which is quite correct! We will continue the pot experiments and explore the effect of fertilizer on the productivity and quality of tea in future.
Last but not the least, all the comments were revised in the manuscript.
Thank you and all the reviewers for the kind advice.
Sincerely yours,
Huan Li
Author Response File: Author Response.docx
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.
