Study of the Humification Process and Humic Acid-like Structure Characteristics of Kitchen Waste with the Addition of Biochar

Round 1

Reviewer 1 Report

Beside the comments below, authors should revise the comments made on provided PDF annoted copy of their submitted manuscript.

The scientific soundness, the significance of Content, the quality of presentation and therefore the interest of the readers may be significantly improved if authors provide answers or modifications to the following 3 points:

1.      Lack of hypothesis and objective(s)

No hypothesis or objective(s) are clearly stated at the end of the Introduction section. From the point of view of the readers, this considerably reduces the understanding of the scientific process and the meaning of the results, points of discussion and conclusions presented by the authors. It is thus difficult to appreciate the innovative scientific soundness aspects promoted by the article.

2.       Lack of detailed information on biochar properties/characteristics

The interest of the readers is to be able to reproduce the results and to fully appreciate the impact of the intrinsic properties of the biochar on: (1) the results observed during the process of composting kitchen waste with or without the biochar, and (2) the resulting properties and amounts of HAL, FAL, HML, TOC, TN measured during composting of KC and KCBr mixtures.

The absence of detailed information on the source of the materials subjected to pyrolysis, the pyrolysis conditions and the intrinsic physical and chemical characteristics of the biochar considerably reduce the reproducibility of the results, the scientific significance of the submitted manuscript and the scientific value of the approach followed by the authors.

3.      Lack of using relative content % of each product (TOC, TN, HAL, FAL, HLM) to statistically compare the effect of KC and KCBr mixes on composting performances:

In table 2, the authors observed that the initial quantities of the products (TOC, TN, HAL, FAL and HML) differed according to the mixture (KC or KCBr) used. They performed the statistical analysis of the content detected in the samples, expressed as absolute values, to determine the effect of the sampling period during the composting process of each mixture. Table 2 indicates the significant increasing or decreasing variations of the quantities of the products during the composting process of each mixture. However, the authors did not statistically analyze the effects between compost mixes.

In addition, the column of HAL values, expressed as relative content %, clearly indicates the interest of using the values of each product expressed as relative content %, in order to better interpret the comparison of compost mixes and the effects of the sampling period during the composting process.

Beside the above 3 global comments, the authors should revise the comments made on provided PDF annotated copy of their submitted manuscript. 

Few word corrections are proposed. Several comments are respectfully provided to highlight unclear statements or to suggest that in M&M sections 2.3 to 2.6 detailed information and at least one reference should be provided. In Results section, especially for Fig 2 and Table 3, authors should considered my comments on expressing product content measured values as product relative content % values to better interpret the results.

Finally, as a general comment on the discussion section, I very much appreciated the exhaustive presentation of the authors' arguments and conclusions published by other authors to clearly explain the functions and effects of soil biology or composting mixtures biology that could explain the results reported in this manuscript. In this context, I wonder about the justification of the authors for not having included at least one if not a few biological parameters to be measured in the content of the mixtures before and during the composting process. 

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 1 Comments

Point 1: Lack of hypothesis and objective.

Response 1: If the current hot spot material -- biochar is selected for humification culture, its humification process can be efficiently promoted? What are the differences between the structural characteristics of the culture product--humic acid-like, and the treatment without biochar?

  To answer the above questions, in this study, we choose to add biochar were humified for 24 days, using the indoor static composting method. The HAL were analyzed using elemental analysis, infrared spectroscopy, and differential thermal techniques, which provided a basis for clarifying whether there were differences in the structure of HAL obtained by adding biochar and whether adding biochar could efficiently promote the humification process. (in red)

Point 2: Lack of detailed information on biochar properties/characteristics.

Response 2: Biochar is made from corn straw under anaerobic conditions at 500-600℃. Before preparing the biochar, the corn straw was dried in an oven at 80 ℃ for 12 hours. The corn straw is put into the carbonization furnace, vacuumized, and then filled with nitrogen for 3 times. In the oxygen free state (filled with high-purity nitrogen), slowly raise the temperature to 400 ℃ (the initial set temperature of the carbonization furnace is 200 ℃, increasing by 100 ℃ every 3 hours). (in red)

Point 3: Lack of using relative content % of each product to statistically compare the effect of KC and KCBr mixes on composting performances.

Response 3: 

 Point 4: Comments: In this context, I wonder about the justification of the authors for not having included at least one if not a few biological parameters to be measured in the content of the mixtures before and during the composting process.

Response 4: We have determined the index of microbial biomass carbon and the content of lignocellulose in the process of humification culture. However, our research group wants to write another article combining high-throughput sequencing after integrating the data indicators on biomass, so this article does not reflect the results of biomass measurement.

Point 5: Several comments are respectfully provided to highlight unclear statements or to suggest that in M&M sections 2.3 to 2.6 detailed information and at least one reference should be provided.

Response 5: 2.4 Compost culture experiment: (1) The moisture content was adjusted only once at the beginning of the experiment. (2) The same treatment is packed in three foam boxes for indoor static composting. The sampling method is multi-point mixing method. Take the same amount (50g) of samples from the upper layer, middle layer and lower layer of the pile respectively, and mix them evenly. 2.6 Need to cite reference(s): The references has been added. (in red)

Point 6: Figure 2 tittle.

Response 6: “effect” was marked in red. 

  Point 7: Results, paragraph 4, line 5, line 10.

Response 7: “humification” was marked in red.

Point 8: Discussion, paragraph 1, line 9-10. 

Response 8: This sentence refers to the second temperature rise of the material on the 18th day in combination with Figure 1(a). The reason for the temperature rise may be that I provided sufficient oxygen after turning the stack.

Point 9: Conclusions, line 3.

Response 9: “TOC, HLM and FAL” has been marked in red.

 Thank you very much for all the suggestions you have made for this article, which has provided great help and inspiration for my future paper writing and made up for my many shortcomings in writing. Thank you very much again.

Author Response File: Author Response.doc

Reviewer 2 Report

The manuscript entitled "Study of the humification process and humic acid-like structure characteristics of kitchen waste with the addition of biochar" by Long Ming et. al., studies the effects on humification process after applying biochar to other wastes, which is a good direction worthy of attention. Methods are not comprehensively described and there is too little statistical and rational analysis of data. This is why, with the actual results, authors can not firmly reach the mentioned conclusions. Thus, I would only recommend that the manuscript is considered suitable for publication in Agronomy after resubmitting and reconsidering all suggestions are correctly performed.

The objective or aim is written in the abstract, but not in the introduction section. If the objective is to determine which changes occurs with the addition or not of biochar, statistical analysis must be performed between treatments, not only between days for the same treatment.

I would recommend to improve the materials and methods section, as many of them are few explained or referenced. All equipment used should have the model, branch and city.

For all data, mean±standard deviation must be provided and in the correct way (according with significant numbers, decimals).

 Revise the template as sustainability and agronomy journals are mixed.

All keywords appear in the title, and one is bad written. Consider changing them.

Be consistent along the manuscript with units. Write g kg^-1 or g/kg in all manuscript. All tables need to be understandable and easy to read. Units of the results must be written,

Check all references. Many of them are in capital letters, others are in lowercase letters. Reference 47 in the list is not in the correct format.

Please, check the term humization and change it for humidification along the manuscript.

More suggestions are included in the pdf attached.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2 Comments

 Point 1: Key words.

Response 1: humification was marked in red.

Point 2: Template.

Response 2: Agronomy was marked in red.

Point 3: Introduction,paragraph 1, line 22.

Response 3: HLS has been deleted.

Point 4: Introduction,paragraph 3, line 6, line10.

Response 4: The capital letters has been changed to lowercase letters. (in red)

Point 5: Objectives? aims? 

 Respinse 5: The objectives or aims are written in the last paragraph of the introduction. (in red)

Point 6: Please, explain in detail how was biochar produced.

Response 6: Biochar is made from corn straw under anaerobic conditions at 500-600℃,Before preparing the biochar, the corn straw was dried in an oven at 80 ℃ for 12 hours. The corn straw is put into the carbonization furnace, vacuumized, and then filled with nitrogen for 3 times. In the oxygen free state (filled with high-purity nitrogen), slowly raise the temperature to 400 ℃ (the initial set temperature of the carbonization furnace is 200 ℃, increasing by 100 ℃ every 3 hours). (in red)

Point 7: Table 1. have the raw material data without standard deviation.

Response 7: Changed. Refer to the Table 1 in the article. (in red)

Point 8: Fresh sample is used for pH and EC. Were they dried prior to the analysis? Please,explain the protocols.

Response 8: The pH and EC were determined without drying, and fresh samples were used. Because the extraction solution of the sample is used for the determination.

Point 9: Questions about sample collection.

Response 9: I'm very sorry that my writing is not standardized, which has caused you trouble. In this study, the pH, moisture content and EC in the composting process were analyzed by collection every three days. When analyzing the humus composition, the samples were collected at days 0, 12, and 24 of incubation. (in red)

Point 10: Was TN determined in the fresh sample?

Response 10: No. TN was determined in fresh samples. Because air dried samples are used for testing.

Point 11: Low-speed ? High-speed?

Response 11: Low-speed: 4000r/min, 15min; High-speed: 11000g, 15min. (in red)

Point 12: Did authors test the normality and homocedasticy of data?

Response 12: I’m very sorry that I didn’t write it clearly, which brought you doubts. Normal distributionand Homogeneity of variance test analysis have been conducted. Refer to the red mark in the article. (in red)

Point 13: It is difficult to see figure 1.

Response 13: Figure 1. has been readjusted.

Point 14: Title is redundant.

Response 14: Changes in the parameters during mixed composting of kitchen waste and biochar. (in red)

Point 15: Please add references.

Response 15: GB 7959-2012, Hygienic requirements for harmless disposal of night soil. Standards Press of China, 2013.

Point 16: Table2. Units.

Response 16: Refer to the Table 2. in the article. (in red)

Point 17: What is HML?

Response 17: Humin-like (HLM). (in red)

Point 18: It is difficult to see figure 2.

Response 18: Figure 2 has been readjusted.

Point 19: Space missing.

Response 19: Spaces has been added. (in red) 

Point 20: Effcets?

Response 20: Effects was marked in red.

Point 21: Space missing.

Response 21: Spaces has been added. (in red)

Point 22: Element?

Response 22: elemental was marked in red.

Point 23: Table 3. Is it C or TOC?

Response 23: This is the carbon.

Point 24: Atomic ratio or molar ratio?

Response 24: C/N, H/C, O/C are all molar ratio.

Point 25: FTIR spectra.

Response 25: FTIR spectra. (in red)

Point 26: Results, paragraph 6, line9-10.

Response 26: This sentence has been deleted.

Point 27: Irrelevant figure. It is not important.

Response 27: Figure 4 (b). has been deleted.

Point 28: The medium and high were should be explained.

Response 28: The medium means medium-temperature (334-357 °C); The high means high-temperature (419-659 °C).

Point 29: How is it significant.

Response 29: There was a significant change in the KCBr heat-temperature exothermic peak at 24 d, while the DTA curve of the KC only slightly changed from 0 d.

Point 30: Results, paragraph 8, line9, line 17.

Response 30: Humification was marked in red.

Point 31: For discussion, results must be better statistically analysis and probably, this part will be rewirtten?

Response 31: First of all, thank you very much for your valuable comments and suggestions on this article. I am pleased to accept your opinion that there should be better data analysis to fill in the discussion. Because the quantitative data analysis in this article is really limited, it may not meet your expectations for a large number of data analysis can be added to the discussion. I am very sorry for that. I have tried my best to use the existing data to fill in this part of the discussion. Finally, thank you very much for all the suggestions you have made for this article, which has provided great help and inspiration for my future paper writing and made up for my many shortcomings in writing. Thank you very much again.

Point 32: Discussion, paragraph 3, last sentence.

 Response 32: Elemental was marded in red.

Point 33: Better data analysis should be performed to reach these conclusions.

Response 33: The calculated data has been added to the conclusion. (in red)

Point 34: Conflicts of Interest.

Response 34: Declare was marked in red.

Point 35: The format of references.

Response 35: The format of references has been corrected. Refer to the red mark in the article. (in red)

Author Response File: Author Response.doc

Reviewer 3 Report

Dear Editors and Authors,

 List of comments

Introduction

Paragraph 1

Line 3              “biochars at high temperatures (< 700 °C) under hypoxia or low oxygen environment”  -  Biochars are produced at different temperatures (also lower than 700°C) and in different gases. Please specify in what temperature range and in what shielding gases biochar is produced. Biochar can have different properties depending on the temperature and shielding gas and can affect the humification process differently.

Line 8-10       “The addition of biochar significantly alters the structure of the microbial community, increases microbial activity and diversity, and promotes further degradation of organic matter, thereby affecting the stability of the soil organic carbon.” -  Always and every type of biochar works like this?

Line 10-16     “Studies have indicated that adding biochar to the same heap of material during composting can rapidly increase the temperature of the heap—usually 6–7 d earlier when the heap enters the high-temperature period—and can also extend the high-temperature period, thereby promoting the degradation rate of organic matter and significantly accelerating the composting process [6–9].”  -  Please provide a brief description of the biochars (feedstock, temperature, shielding gas) as it is of great importance how the biochar affects microorganisms.

Line 18           “believed”...? -   Did they believe or did they investigate?

Line 20           “Dias et al. [12] applied biochar in the composting process to enrich the humus in a heap. Here, the humic acid content in the alkali extract of the fertilizer reached 900%.”  -  When giving the "900%" value, you must relate it to the base value (biochar (dose) increased the C content compared to ...)

Line 22           “Biochar generates humic acid (HLS) and other organic matter in the pyrolysis process that can adsorb to the surface of biochar and consequently enter the soil”  - ???  Did the authors understand the sentence: "water-soluble aromatic structures similar to fulvic-like SOC; (C2–C3) aromatic structures similar to humic-like SOC having low water solubility that decomposed above 350 °C"? [13]

Paragraph 2

Line 13           “Humus will be formed when the corn stalk decomposes, a process that requires energy.” -  "requires energy" ? Could you please explain?

Paragraph 2

Line 1              “Humification, typically described as the transformation of biochar waste into a stable humic substance (HS) [18],”  -  “biochar waste” Could you please explain?

Line 6, 8, 10 “HARDIE et al. [21], WU et al. [22], AMIR et al. [20]” - Why did you use capital letters?

Line 10           “HA” - ? or “humic acid (HLS) (line 22 Paragraph 1). This is confusing: H, HA, HS ...

There is no clearly defined aims of the research in the introduction.

Materials and Methods

Paragraph 1

Line 4              “washed several times with deionized water to remove the upper layer of the oil slick”  -  Why was the oil removed?

Paragraph 3

Line 1              It is very important to add a description of the biochar (feedstock, temperature, shielding gas, etc.) used in the research.

Paragraph 4

Line 4             “the pH was natural”  -  ?

Paragraph 8

Line 6, 13, 16     “centrifugation at low speed.” “high-speed centrifugation” -  Please specify the centrifugation speed and the time.

Table 2.          „HML” - ?

Discussion

Paragraph 1

Line 15-25     Humidity was not a factor in the authors' study. A description of the impact of water on the composting process is redundant.

Line 30-34     Please verify Yingting Li [33] research results with your own research results.

LIne ..             “The conductivity reflects the total soluble salt content in the kitchen garbage extract,...” - Please focus on explaining the effects of biochar added to kitchen waste in terms of electrical conductivity as well as throughout the discussion.

In summary, the manuscript can be accepted for publication in the Agronomy after some revisions.

Best regards

Author Response

Response to Reviewer 3 Comments

 Point 1: Introduction, Paragraph 1, Line3. “biochars at high temperatures (< 700 °C) under hypoxia or low oxygen environment” - Biochars are produced at different temperatures (also lower than 700°C) and in different gases. Please specify in what temperature range and in what shielding gases biochar is produced. Biochar can have different properties depending on the temperature and shielding gas and can affect the humification process differently.

Response1: Biochar is made from corn straw under anaerobic conditions at 500-600℃. Before preparing the biochar, the corn straw was dried in an oven at 80℃ for 12 hours. The corn straw is put into the carbonization furnace, vacuumized, and then filled with nitrogen for 3 times. In the oxygen free state (filled with high-purity nitrogen), slowly raise the temperature to 400℃ (the initial set temperature of the carbonization furnace is 200℃, increasing by 100℃ every 3 hours). (in red)

Point 2: Line8-10. “The addition of biochar significantly alters the structure of the microbial community, increases microbial activity and diversity, and promotes further degradation of organic matter, thereby affecting the stability of the soil organic carbon.” -  Always and every type of biochar works like this?

Response 2: This statement is quoted from the reference. From the structure, biochar has the characteristics of loose and porous, so its surface area increases, providing more habitats for microorganisms, and increasing the diversity and quantity of microorganisms. In the process of aerobic composting, microorganisms are mainly involved in activities. Therefore, more microbial populations bring more organic matter to be degraded. In the process of composting, more organic matter is degraded with high efficiency, more humus is formed, and more stable organic carbon is obtained.

Point 3: Line10-16. “Studies have indicated that adding biochar to the same heap of material during composting can rapidly increase the temperature of the heap—usually 6–7 d earlier when the heap enters the high-temperature period—and can also extend the high-temperature period, thereby promoting the degradation rate of organic matter and significantly accelerating the composting process [6–9].”  -  Please provide a brief description of the biochars (feedstock, temperature, shielding gas) as it is of great importance how the biochar affects microorganisms.

Response 3: Biochar is made from corn straw under anaerobic conditions at 500-600℃. In the oxygen free state (filled with high-purity nitrogen).

Point 4: Line18. “believed”...? -  Did they believe or did they investigate?

Response 4: This sentence is the reference I quoted, and the author reached a conclusion through his own experiment. The PHA (percentage of humic acids) value in Table 3 of the original text is higher than that of the other two treatments without adding biomass carbon at each composting stage. See Table 3 below for details.

Table 3. Humification indexes of different organic waste during composting process.

DP, degree of polymerisation; HR, humification ratio; HI, humification index; PAH, percentage of humic acids. Columns sharing the same letters do not differ significantly according to mean separation by Duncan’s multiple range test at probability level P < 0.05.

Point 5: Line20. When giving the "900%" value, you must relate it to the base value (biochar (dose) increased the C content compared to ...)

Response 5: I'm sorry that this sentence has caused you confusion. After I read the cited original literature again, the original meaning should be”At the end of the composting process, the humic acid fraction represented more than 90% of the alkali extractable fraction, reflecting the intense humification of this material.”I made mistakes in the process of editing, with 900% errors. (in red)

Point 6: Line22. “Biochar generates humic acid (HLS) and other organic matter in the pyrolysis process that can adsorb to the surface of biochar and consequently enter the soil”  - ???  Did the authors understand the sentence: "water-soluble aromatic structures similar to fulvic-like SOC; (C2–C3) aromatic structures similar to humic-like SOC having low water solubility that decomposed above 350 °C"? [13]

Response 6: My understanding is that biochar itself has strong adsorbability. Literature review shows that the structure of biochar contains a large number of alkyl and aromatic structures [1], which can stably exist in the soil and is an important part of the soil carbon pool [2].

References:

1. Zhang A-feng, Pan Gen-xing, Li Lian-qing. Biochar and the effect on C stock enhancement, emission reduction of greenhouse gases and soil reclaimation[J]. Journal of Agro-Environment Science, 2009, 28 (12): 2459-2463.
2. Woolf D. Biochar as a soil amendment：A review of the environmental implications[M]. Swansea：Swansea University, 2008.
3.  

Point 7: Paragraph2,line13. “Humus will be formed when the corn stalk decomposes, a process that requires energy.” -  "requires energy" ? Could you please explain?

Response 7: Humus substances (HS) are the final product of humification process. The humification process of straw aerobic compost is similar to that of soil humification, which is the most typical humification process[1]. Decomposition requires the participation of microorganisms. When microorganisms decompose crop residues, they need energy generation and exchange. Simple compounds are decomposed to form humus through polymerization.

References:

1. Tang Jing-chun, Sun Qing, Wang Ru, et al. Progress in the formation, evolution and application of humic acid during composting[J]. Environmental Pollution and Prevention, 2010 (5): 73-77, 88.
2.  

Point 8: Paragraph3, line1. “Humification, typically described as the transformation of biochar waste into a stable humic substance (HS) [18],”  -  “biochar waste” Could you please explain?

Response 8: I'm sorry that my mistake has caused you trouble. The two words biochar waste should not be used together. My understanding is that solid waste is converted into biochar to form stable humus. (in red)

Point 9: Line6, 8, 10. “HARDIE et al. [21], WU et al. [22], AMIR et al. [20]” - Why did you use capital letters?

Response 9: Changed. (in red)

Point 10: Line10, HA,HLS...“HA” - ? or “humic acid (HLS) (line 22 Paragraph 1). This is confusing: H, HA, HS ... There is no clearly defined aims of the research in the introduction.

Response 10: I want to prove that the addition of biochar carbon has improved the composting effect through reference, so as to confirm this experiment.

Point 11: Materials and Methods，Paragraph 1, Line 4. Why was the oil removed?

Response 11: First of all, kitchen waste in China is characterized by high oil content, especially in the north. Secondly, after several times of composting without oil removal, the effect is very bad, especially easy to cause anaerobic, leading to the generation of odor. After repeated composting to ensure that other composting conditions remain unchanged, the final judgment is that the oil content is too high, so we want to remove some of the oil.

Point 12: Paragraph 3, Line 1. It is very important to add a description of the biochar (feedstock, temperature, shielding gas, etc.) used in the research.

Response 12: Biochar is made from corn straw under anaerobic conditions at 500-600℃. In the oxygen free state (filled with high-purity nitrogen).

Point 13: Paragraph 4, Line 4. “the pH was natural”  -  ?

Response 13: The pH of kitchen waste is determined after removing oil, the pH of corn straw is determined by crushing, and the pH of biochar carbon is determined directly.

Point 14: Paragraph 8, Line 6, 13, 16.“centrifugation at low speed.” “high-speed centrifugation” -  Please specify the centrifugation speed and the time.

Response 14: “centrifugation at low speed.” 4000r/min,15min; “high-speed centrifugation”11000g,15min. (in red)

Point 15: Table 2.HML?

Response 15: HLM means Humin-like. (in red)

Point 16: Discussion, Paragraph 1, Line 15-25. Humidity was not a factor in the authors' study. A description of the impact of water on the composting process is redundant.

Response 16: The discussion in this part is based on the composting itself, because the moisture content is an important factor at the start of composting, and the moisture content at the end of composting can also reflect whether the composting material is more mature.

Point 17: Line 30-34. Please verify Yingting Li [33] research results with your own research results.

Response 17: The research of LiYingTing is actually inconsistent with my research results. My research results are that the water content after adding biochar is higher than that of the treatment without adding biochar at the end of composting. Because the porosity of biochar itself increases, there will be some water vapor between the pores. However, LiYingTing shows that the addition of biochar increases the porosity between material stacks, which will accelerate the exchange capacity with external gas.

Point 18: Please focus on explaining the effects of biochar added to kitchen waste in terms of electrical conductivity as well as throughout the discussion.

Response 18: The addition of biochar and organic manure decreased soil EC when compared to their initial readings. Similar reductions in soil EC were reported by [1] and [2], when organic manures and composts were added to saline soils. The improving impacts that combination of biochar and pig manures had on different parameters of soil might be a consequence of the enhanced level of nutrients. K, Ca, Mg, and Na in the organic amendments (pig manure) may have also contributed to the increase of the exchangeable bases. The EC is total dissolved salts in sample and addition of biochar and organic manure raised soil EC. This reduction in soil EC agrees with report of [1] and [2], who reported reduction in soil EC when organic manures and composts were added to saline soils. The increase in EC is probably due to the ion rise in the solution,  which may have resulted from mineral dissolution [3], or the formation of organic acids [4] . The electrical conductivity (EC) of the compost is used to characterize the content of soluble salt in the compost. The adsorption of biomass carbon reduces the salt dissolved in water, thereby reducing the EC value of the compost [5]. It is generally believed that compost can only be safely applied to the soil [6,7] when the electrical conductivity of the composted heap is less than 4.0 ms cm^-1, otherwise it may cause toxicity or inhibition to the growth of plants [8]. The conductivity value of soil extract can reflect the soil salt content. In a certain range, the salt content of the solution is positively correlated with the conductivity. Soinne et al. [9] research shows that the application of biochar under wet conditions can reduce soil EC, which may be related to the formation of cation bridge bonds involved in the construction of soil aggregates, thus reducing the content of soluble ions in soil. In addition, Quilliam et al. [10] concluded that the reduction value of soil EC was positively correlated with the amount of biochar used, indicating that biochar could promote the leaching of soil salt and reduce soil salt content.

References

1. Ghafoor, A, G. Murtaza, M. Rehman and M. Sabir . "Reclamation and salt leaching efficiency for tile drained saline-sodic soil using marginal quality water for irrigating rice and wheat crops.”Land Degradation & Development, 2012, 23(1): 1-9.
2. Tejada, M, C. Garcia, J. Gonzalez and M. Hernandez . "Use of organic amendment as a strategy for saline soil remediation: influence on the physical, chemical and biological properties of soil.”Soil Biology and Biochemistry, 2006, 38(6): 1413-1421.
3. Flavel, T. C.and D. V Murphy . "Carbon and nitrogen mineralization rates after application of organic amendments to soil.”Journal of Environmental Quality, 2006, 35(1): 183-193.
4. Wong, V. N., R. C. Dalal and R. S. Greene "Carbon dynamics of sodic and saline soils following gypsum and organic material additions:laboratory incubation.” Applied Soil Ecology, 2009, 41(1):29-40.
5. Li L J,Effects of bamboo charcoal on nitrogen conservation and greenhouse gas emissions reduction during swine manure composing, Master Dissertation, Zhejiang University, Hangzhou, China, 2012.
6. Bao S D. soil and agricultural chemistry analysis. M, China Agriculture Press, 2000.
7. Cathcareep, Wheaton F W, Brinsfield R B. Optimizing variables affecting composting of blue-crab scrap J. Agricultural Wastes, 1986, 15(4): 269-287.
8. Zhang Y, He Y. Co-composting solid swine manure with pine sawdust as organic substrate J. Bio-resource Technology, 2006, 97 (16): 2024-2031.
9. Quilliam RS, Deluca th, Jones dl. Biochar application reduces nodulation but increases nitrogenase activity in clover. Plant and Soil, 2013, 366:83-92.
10. Soinne H, Hovi J, Tammeorg P, Turtola E. Effect of biochar on phosphorus sorption and clay soil aggregate stability. Geoderma, 2014, 219: 162-167.

  Thank you very much for all the suggestions you have made for this article, which has provided great help and inspiration for my future paper writing and made up for my many shortcomings in writing. Thank you very much again.

Author Response File: Author Response.doc