Modification of Soil Physical Properties by Maize Straw Biochar and Earthworm Manure to Enhance Hydraulic Characteristics under Greenhouse Condition
, Tingting Chang 1 and Yousef Alhaj Hamoud 1,*Round 1
Reviewer 1 Report
Dear authors: The manuscript needs a major revision. Please see all my comments. The paper lacks a scientific approach to writing a manuscript. It looks like a loosely written paper. Grammar and English writing are very poor. The results presented are not clearly written. Many times points seem to be repeated. Overall the research is not bringing up any new findings. Add more citations in the discussion section to support your findings.
Overall, this needs a lot of rework.
Comments for author File: 
Comments.pdf
Author Response
Comment 1: The paper lacks a scientific approach to writing a manuscript. It looks like a loosely written paper. Grammar and English writing are very poor.
Response: We apologize for the language problems in the original manuscript. We checked the whole article carefully to improve the English writing. The language presentation was improved with assistance from a native English speaker with appropriate research background, so we hope it can meet the journal’s standard.
Comment 2: The results presented are not clearly written. Many times points seem to be repeated.
Response: We are sorry for not addressing the Conclusions description clearly. We have rewritten the part in the section of conclusions as the following: “In our study, both biochar and earthworm manure at different application rates positively affected soil physical properties, mainly at the high application rate of 5% biochar. With increasing biochar application rates, soil BD was effectively reduced, soil physical properties were improved, contributed to the improvement of water retention and infiltration, enhanced SWCC and KS, eventually increased FC and AWC. However, at the same application rate, biochar was significantly more effective in enhancing TP than earthworm manure, resulting in significantly higher KS, FC, and AWC in BA3, BA5 than in QA3, QA5. The AWC increased from 14.1% to 18.0%, 18.0%, 20.9%, and 21.9% under CK, QA3, QA5, BA3, and BA5, respectively. Therefore, under the present experimental conditions, maize straw biochar was more effective than earthworm manure in improving the physical properties and hydraulic characteristics of the facility soil, and 5% biochar was the most effective in improving soil water availability.”
Comment 3: Overall the research is not bringing up any new findings. Add more citations in the discussion section to support your findings.
Response: We are grateful for the suggestion. To be more clear and in accordance with the reviewer concerns, we have added more citations in the discussion section to support our findings in the original manuscript.
Comment 4: Title “Maize Straw Biochar and Earthworm Manure-induced Modification of the Soil Physical Properties Enhances Hydraulic Characteristics in Facility Agriculture” is not very clear……! Reframe the title.
Response: We are grateful for the suggestion. To be more clear and summarize the content of the paper more precisely, the title of the manuscript is adjusted to “Modification of Soil Physical Properties by Maize Straw Biochar and Earthworm Manure to Enhance Hydraulic Characteristics under greenhouse condition”.
Comment 5: “(X.L.); (J.Z.); (Q.W.); (H.S.); (T.C.); (Y.A.H.)” why there are so many abbreviations?
Response: We deeply appreciate the reviewer’s suggestion. These abbreviations are the names of the respective authors and have been supplemented in the manuscript with the complete words. X.L. — Xinna Liu; J.Z. — Jie Zhang; Q.W. — Qian Wang; H.S. — Hiba Shaghaleh; T.C. — Tingting Chang; Y.A.H. — Yousef Alhaj Hamoud.
Comment 6: 210098?
Response: We deeply appreciate the reviewer’s suggestion. 210098 is the postal code of the author's address.
Comment 7: “facility agriculture.” what is facility in this context? This should be about general in the larger context.
Response: Thank you for your careful reading of our manuscript. According to Baidu Encyclopedia, in the larger context, Facility agriculture is a facility project that uses artificial technology to change natural light and temperature conditions to create environmental factors that optimize the growth of plants and animals so that they can grow around the clock. In our manuscript, facility agriculture refers to plastic greenhouse in facility horticulture.
Comment 8: “Thus, setting up pot experiment with five soil treatments of 0% (CK, No additives), 3% biochar (BA3, Mass ratio), 3% earthworm manure (QA3), 5% biochar (BA5), and 5% earthworm manure (QA5) to investigate the effects on soil physical properties and hydraulic characteristics in facility agriculture.” It could be written like “An experiment was set up with five soil treatments……”.
Response: We deeply appreciate the reviewer’s suggestion. According to the reviewer’s comment, we have rewritten this section like “An experiment was set up with five soil treatments of 0% (CK, No additives), 3% biochar (BA3, Mass ratio), 3% earthworm manure (QA3), 5% biochar (BA5), and 5% earthworm manure (QA5) to investigate the effects on soil physical properties and hydraulic characteristics under greenhouse condition”.
Comment 9: “The results showed as follows, the soil total porosity(TP), saturatedhydraulic conductivity (KS), field capacity (FC), permanent wilting point (PWP), and available water content (AWC).” You could say “ the soil physical properties were measured based on the soil total porosity, ......” Then talk about the results......,The results showed that.
Response: Thanks for the reviewers' comments, we have revised it according to the reviewers' comments as follows: The soil physical properties were measured based on the soil bulk density (BD) and total porosity (TP), the results showed that BA5 provided the lowest soil BD (1.24 g·cm-3) and the highest TP (53.09%), and was 13.8% higher than CK. What’s more, saturated hydraulic conductivity (KS), field capacity (FC), permanent wilting point (PWP), and available water content (AWC) treated with biochar and earthworm manure were significantly higher than those of CK, and the effect of applying biochar with the same application rate on soil water permeability and water retention capacity was significantly improved than that of earthworm manure, in which the soil-water characteristic curve (SWCC) showed as BA5 > BA3 > QA5 > QA3 > CK, the FC and AWC increased from 28.90% and 14.13% under CK, respectively, to 40.73% and 21.91% under BA5, respectively, the KS, FC, PWP and AWC of BA5 highest increased by 45.93%, 40.91%, 27.46% and 54.96% than CK, respectively.
Comment 10: “tight land resources.” Do you mean scarcity of resources?
Response: We are sorry for not addressing the “tight land resources” description clearly. The “tight land resources” refers to “As the population grows and human needs increase, the shortage of land resources is also becoming increasingly serious.”
Comment 11: “facility agriculture.” not a generic term.
Response: Thank you for your instructive suggestions. We are sorry for not clearly describing this generic terminology, and we have changed the “facility agriculture” to “plastic greenhouse in facility horticulture” in the original manuscript.
Comment 12: “Biochar and earthworm manure have received much attention for their beneficial effects in improving soil quality.” cite it.
Response: We deeply appreciate the reviewer’s suggestion. According to the reviewer’s comment, We have cited references [8-10] related to “Research of biochar and earthworm manure in soil improvement” in the original manuscript.
Comment 13: “With rich pore structure and huge specific surface area (SSA) and excellent adsorption capacity, biochar has been widely used as a soil amendment with positive effects in improving soil physical properties. The well-developed porous structure of biochar increases the TP of the soil surface layer, and with the increase of biochar application, the soil BD tends to decrease and the soil structure is improved[14, 15]. In addition, biochar can adsorb and retain water, which in turn affects soil water holding capacity and hydraulic conductivity characteristics, and can enhance soil water infiltration, but the specific mechanism needs to be further studied[16-18]. Soil water transport and storage play an important role in nutrient transport and plant growth, and soil water characteristics mainly include soil water holding capacity.” what is new about your research? I dont see any new information and the quality of writing is very poor.
Response: Thanks for the reviewers' comments, our original writing did cause ambiguity, now we revise it and add more new information as follows: “Biochar hasWith rich pore structure and huge specific surface area (SSA) withand excellent adsorption capacity, which has a biochar has been widely used as a soil amendment with positive effects in on improving soil physical properties [13-16]. Soil bulk density (BD) and total porosity (TP) are key indicators of soil physical quality [17], and tThe well-developed porous structure of biochar increases the TP of the soil surface layer, and with increasing biochar applicationthe increase of biochar application, the soil BD tends to decrease and the soil structure is improved [18, 19]. Earthworm manure is a black fine particulate matter obtained from the disposal of biological waste under the digestive system of earthworms with the combined action of various enzymes and microorganisms [20, 21]. Earthworm manure has a large specific surface area, high drainage, high water holding capacity, and good aeration, which increases the number and activity of microorganisms in the soil, easily forming granular structures, reducing soil BD, and increasing TP [22, 23].”
Comment 14: “research[21-23]. soils[25, 26]. soils[27, 28]. soil[29, 30]……” Add space, Please correct across the entire document.
Response: Thank you for your careful reading of our manuscript. We have corrected the space across the entire document.
Comment 15: “The results of Lydia et al.[24] showed that biochar could improve soil physical structure and porosity, thus increasing soil water holding capacity, soil water effectiveness, and improving soil moisture status.” you have to provide more details to the study you are citing here.
Response: Thank you for your careful reading of our manuscript. We have added more details as follows: “The addition of biochar can increase the contact between soil particles and increase the small porosity, thus increasing the soil water retention capacity [33]. Devereux et al. [34] set up incubation tests with different mass ratios of biochar and sandy loam (0.0%, 1.5%, 2.5%, 5.0%) and revealed that soil water content increased with the increasing of biochar application at a certain water potential (10-2 kPa - 104 kPa).”
Comment 16: “And it had advantages in physical properties, and could effectively improve soil structure and improve soil water permeability.” Do not begin a sentence with And.
Response: Thank you for your careful review. We are very sorry for the mistakes in this manuscript and have been rewritten: “Earthworm manure has advantages in physical properties, which can effectively improve soil structure and soil water permeability”.
Comment 17: “Under the current water scarcity,” its incomplete sentence.
Response: Thank you for your careful reading of our manuscript. We have rewritten the sentence in the revised manuscript as the following: In the current context of water scarcity, the effects of biochar and earthworm manure on the physical properties and hydraulic characteristics of soil in facilities need to be further investigated.
Comment 18: “a 6.3 mm sieve.” why such a wide pored sieve? Is your soil granular?
Response: Thank you for your comment, and our reply is as follows: Our experimental soil is not granular, it is air-dried powdered loam, and the 6.3 mm sieve is used to remove debris from the soil.
Comment 19: “yellow-brown loam.” Textural composition of soil, silt and clay?
Response: Thank you for your instructive suggestions. We are sorry for not describing the clay, silt, sand of soil. According to your helpful advice, we have added the part in the section of 2.1. Soil sampling: soil texture was measured by Bouyoucos hydrometer (TM-85, SHTG, Shanghai, China) [49], with the clay: 26.5%, silt: 34.9%, sand: 38.6%.
Comment 20: “the Chinese classification [42],” what is chinese clasification? it should be according to USDA-NRCS classification.
Response: Thank you for your careful reading of our manuscript. By consulting the relevant references of soil texture classification, we cited the “Chinese soil taxonomy. Beijing: Science press.”
Comment 21: “The correlation analysis between soil physical properties (BD, TP) and hydraulic characteristics (KS, FC, PWP, AWC) are shown in Table 2. According to the correlation coefficient matrix, all hydraulic characteristic parameters (KS, FC, PWP, AWC) showed a strongly significant correlation with BD and TP (R > 0.8), indicating that the improvement of soil physical properties was conducive to improving soil hydraulic characteristics and enhancing soil water availability. Every two of KS, FC, PWP, and AWC had a highly significant positive correlation (R > 0.6). Moreover, PWP and AWC showed strongly significant correlation with FC (R > 0.8), indicating that the FC was most closely related to AWC, which was conducive to improving soil permeability and increasing soil water holding capacity.” Please improve the presentation of your results write up across the document.
Response: We deeply appreciate the reviewer’s suggestion. According to the reviewer’s comment, we improved the presentation of your results write up across the document as the following: “The correlation analysis between soil physical properties (BD, TP) and hydraulic characteristics (KS, FC, PWP, AWC) are shown in Table 2. According to the correlation coefficient matrix, all the hydraulic characteristic parameters (KS, FC, PWP, AWC) showed highly significantly correlated with BD and TP (R > 0.8), indicating that the improvement of soil physical properties was conducive to the improvement of soil hydraulic characteristics and enhancing the soil water availability. Every two of KS, FC, PWP, and AWC had a highly significant positive correlation (R > 0.6). In addition, PWP and AWC showed strongly significant correlation with FC (R > 0.8), indicating that the FC was most closely related to AWC, which was conducive to improving soil permeability and enhancing soil water holding capacity.”
Comment 22: “Our study supported by Wang et al.” study or results.
Response: Thanks to the reviewers' comments for the wording correction, we thought both “study” and “results” are fine, and “results” is more appropriate, we have corrected it in the original manuscript.
Comment 23: “Our results are championed by Lu et al.[62], who communicated that biochar application was positively correlated with FC, and the addition of 2%, 4% and 6% biochar to the clay soil increased the FC by 12%, 20% and 31%, respectively.” championed? Can you write more scieentifically?
Response: Thank you for your careful review. We are very sorry for the mistakes in this manuscript and inconvenience they caused in your reading. We have carefully examined and corrected the mistakes in the manuscript as follows: “Our results are supported by Lu et al. [69], who revealed that biochar application was positively correlated with FC, with the addition of 2%, 4% and 6% biochar to the clay soil increasing the FC by 12%, 20% and 31%, respectively.”
Comment 24: “this may be explained by our experience was carried out for a short period,” grammatical errors.
Response: We deeply appreciate the reviewer’s suggestion. We are very sorry for the grammatical errors and have rewritten the part as follows: “This may be explained by our experiment was conducted over a short period, the effects of biochar and earthworm manure on the AWC of soil were related to their type, application rate, soil conditions and the experiment time”.
Comment 25: “impact mechanism,” what is impact mechanism?
Response: Thanks for the reviewers' comments, our original writing did cause ambiguity, now we revise it according to the reviewers' comments as follows: “It is necessary to further investigate the impacts of biochar and earthworm manure on soil hydraulic characteristics through long-term experiments”.
Author Response File: Author Response.pdf
Reviewer 2 Report
The work presented in the manuscript is timely and important. There is no argument on that matter. The methodology is very scientific and well-planned, and the findings have been presented very nicely.
One of my concerns is the novelty of the work. There has been a lot of research on work focusing on biochar and earthworm cast separately, as pointed out by the researchers themselves. Their findings are also inline with previous published work. What is the logic behind comparing the performance of the use of biochar on the one hand, and earthworm cast on the other hand? The selected are 2 different soil conditioning methods, and apart from these, there are many other methods as well. Please justify the work further, with a very clear distinction on the novelty of the work. If, for example, you experimented with mixing earthworm cast and biochar, in addition to the pure applications, you would be looking at something 'different'.
My second concern is, the findings of this research are very specific. Meaning, within the context of this work, the 5% application of straw biochar out-performed the parallel application of earthworm cast. How would you make your findings be more generic? In what way can this work be valuable to the greater community?
Author Response
Comment 1: One of my concerns is the novelty of the work. There has been a lot of research on work focusing on biochar and earthworm cast separately, as pointed out by the researchers themselves. Their findings are also inline with previous published work. What is the logic behind comparing the performance of the use of biochar on the one hand, and earthworm cast on the other hand? The selected are 2 different soil conditioning methods, and apart from these, there are many other methods as well. Please justify the work further, with a very clear distinction on the novelty of the work. If, for example, you experimented with mixing earthworm cast and biochar, in addition to the pure applications, you would be looking at something 'different'.
Response: Thank you for your careful reading of our manuscript. our explanation is as follows: The porous structure of biochar and earthworm manure could increase the porosity of the soil surface layer, reduce the bulk density and improve the total porosity of the soil, thus increasing soil water-holding capacity and soil water effectiveness, enhancing soil water permeability, improving soil water status and increasing the drought resistance of the ecosystem. Also, our experimental area is Nanjing, Jiangsu Province, China, and biochar and earthworm manure are widely used in facility horticulture in southern China, so these two additives were chosen. Previous studies have mostly been single studies of the two, and this experiment investigates both under the same conditions, allowing for an optimal soil amendment additive solution from an economic point of view.
In addition, the reviewer's concern is necessary for us to pay attention to the soil improvement effect of the single application of biochar and earthworm manure, but also to the soil improvement effect of the mixture of earthworm manure and biochar in different proportions in the later experiments.
Comment 2: My second concern is, the findings of this research are very specific. Meaning, within the context of this work, the 5% application of straw biochar out-performed the parallel application of earthworm cast. How would you make your findings be more generic? In what way can this work be valuable to the greater community?
Response: We are grateful for the suggestion. To be more clear and in accordance with the reviewer concerns, we provided more details to describe this findings as the following: Within the context of this work, the 5% application of straw biochar out-performed the parallel application of earthworm manure. As our experiments were conducted in plastic sheds through pot experiments, the appropriate additive levels obtained can be applied to soil amendments in facility horticulture; however, the results obtained have some limitations in terms of generalizability, and we plan to validate our previously obtained results through field plot experiments at a later stage, followed by large-scale on-farm implementation to obtain more value in he greater community.
Author Response File: Author Response.pdf
