Dependency of Long-Term Soil Quality Controls on Summer Fallow Tillage and Soil Layers for Dryland Winter Wheat in Loess Plateau
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear authors
The title of the manuscript is very interesting. Please see the comments (they are marked with red color) for the complete manuscript. Also, please explain why no-tillage grain yield was lower than other tillage methods. Issues about the application of the NT in the site of the study must be addressed in the text.
Comments for author File: 
Comments.pdf
That was average.
Author Response
Dear reviewer:
I appreciate your comments. We have carefully considered the comments and suggestions and improved the manuscript accordingly.
The responses to the comments are listed below.
Comment 1: The title of the manuscript is very interesting. Please see the comments (they are marked with red color) for the complete manuscript. How you selected these content of the fertilizer. As you know some fertilizers like P and K must be recommended via soil analysis samples.
Response 1: Thanks a lot for the comment. Permit me to explain further. The fertilizer application method in this experiment field is from "Three Advance" Soil Moisture Preservation Technology, which is a demonstrate and predominant planting technique in Shanxi province, China, where has insufficient soil moisture and soil nutrient, and only adequate exogenous fertilizers could ensure plant growth. And the method has been justified in previous study like “Carbon footprint of dryland winter wheat under film mulching during summer-fallow season and sowing method on the Loess Plateau ”.
Comment 2: 16 m2 for yield evaluation is very low area. Its was great you harvest all plot for yield determination. Yield from 16 m2 cannot demonstrate actual yield.
Response 2: Thanks a lot for the comment. According to your comment, we abandoned the yield from 16 m2 and used the grain yield value harvested from all plot field.
Comment 3: Why grain yield was reduced after 4 years in this treatment should explained in this discussion with more details and connect your explain with soil quality results. Also, please explain why no-tillage grain yield was lower than other tillage methods. Issues about the application of the NT in the site of the study must be addressed in the text.
Response 3: Thanks for the comment. Because precipitation is very important for wheat yield in the case, we added the analysis of the interaction between tillage and precipitation during summer fallow on yield in Table 1 and Table 5. The yield verifies the impact of soil quality, but there is a lack of integral data result in the present study. We also added the relationship between yield and SQI as displayed in Table 6.
Previous study elucidated that NT contributes to mitigate disadvantageous effects caused by conventional tillage and increased crop yield. However, continuous no tillage could cause soil compaction in topsoil and subsoil, long-term influence of no tillage is dependent on soil type and climatic conditions. In Loess Plateau region of this experiment, NT decreased soil aggregate stability and increased ρb, resulting in uneven distribution of soil water and nutrient. Decreased SOC and soil nitrogen could reduce root growth, resulting in poor yield. Soil quality reflects integration of soil physical, chemical and biological characteristics. Here, the grain yield was positively correlated with SQI values in 0-10 cm and 40-50 cm soil layers, and PT/ST had the highest value of SQI followed by treatments of 3ST+PT, 3PT+ST and NT (Table 6). These observations agreed the result that grain yield under PT/ST was higher than other treatments, especially than NT. In arid or semiarid filed, precipitation is the dominant environmental factor affecting wheat growth and production. Precipitation during summer fallow (PF) accounts for app. 60% to total precipitation, and it was positively correlated with grain yield in Loess Plateau. Table 1 showed that the PF was extremely low in the fourth year. That’s why the yield reduced in the fourth year (Table 5). In addition, no tillage in dry season could prevent rainfall from infiltrating and maintaining in deep soil, and it is incapable of protecting soil quality. Without sufficient precipitation, NT amplified hardship that winter wheat had high yield.
Yours sincerely,
Zhiqiang Gao
Shanxi Agricultural University
Reviewer 2 Report
Comments and Suggestions for AuthorsID: Agriculture-2994118
Comments:
1. The title is too general. The result of one experiment cannot be generalized to a macroregion.
2. The abstract needs to be corrected. A correctly constructed abstract contains: research hypothesis, basic elements of the methodology, basic results and the final conclusion that summarizes the research. The length of the abstract is of 200 words.
3. Lines 1011: The interaction is between soil tillage and soil properties, not the other way around.
4. Lines 21-22: The conclusion is too general.
5. The keywords have to be significantly different from the title.
6. Introduction: Definitions or description of basic soil characteristics are unnecessary (lines 44-66). It is advisable to shorten these parts.
7. Line 93: From this sentence and figure 5 it follows that wheat was grown in monoculture? This needs to be clarified.
8. Lines 103-106: What was the justification for using such large doses of P and K?
9. Figures presented at this scale are illegible.
10. Wheat yield should be analyzed statistically correctly. The reader expects an analyzis of the interaction between experimental factors and years.
11. Figures 2 and 3: No analysis of the relationship between grain yield and soil properties, as well as SQI.
12. Only if points 10 and 11 are implemted can disscussions be carried out correctly. As it stands, this is just and extended discussion of the results.
Author Response
Dear reviewer:
I appreciate your comments. We have carefully considered the comments and suggestions and improved the manuscript accordingly.
The responses to the comments are listed below.
Comment 1: The title is too general. The result of one experiment cannot be generalized to a macroregion.
Response 1: We have changed the title: Impact of Long-term tillage during summer fallow on soil quality for Dryland Winter Wheat in Loess Plateau.
Comment 2-4: The abstract needs to be corrected. A correctly constructed abstract contains: research hypothesis, basic elements of the methodology, basic results and the final conclusion that summarizes the research. The length of the abstract is of 200 words. Lines 1011: The interaction is between soil tillage and soil properties, not the other way around. Lines 21-22: The conclusion is too general.
Response 2-4: We have rewrite the whole abstract to solve the problems proposed in comment 2, which was highlighted in yellow. The length of the abstract was shorten into 200 words.
Comment 5: The keywords have to be significantly different from the title.
Response 5: We have changed the keyword: Soil quality index; Principal component analysis; Soil physical properties; Soil chemical properties; Triticum aestivum L..
Comment 6: Introduction: Definitions or description of basic soil characteristics are unnecessary (lines 44-66). It is advisable to shorten these parts.
Response 6: The redundant description of soil characteristics has been removed, the revised content was highlighted in yellow.
Comment 7: Line 93: From this sentence and figure 5 it follows that wheat was grown in monoculture? This needs to be clarified.
Response 7: The wheat was grown in monoculture, and was clarified in “experimental design”.
Comment 8: Lines 103-106: What was the justification for using such large doses of P and K?
Response 8: The fertilizer application method in this experiment field is from "Three Advance" Soil Moisture Preservation Technology, which is a demonstrate and predominant planting technique in Shanxi province, China, where has insufficient soil moisture and soil nutrient, and only adequate exogenous fertilizers could ensure plant growth. And the method has been justified in previous study like “Carbon footprint of dryland winter wheat under film mulching during summer-fallow season and sowing method on the Loess Plateau ”.
Comment 9: Figures presented at this scale are illegible.
Response 9: We are sorry for the unreadable figures. The figure 1, 2 and 3 are composed of multiple small images resulting in the illegibility. And we have remade the figures, which are more legible when enlarging pages in Microsoft Word.
Comment 10 and 11: Wheat yield should be analyzed statistically correctly. The reader expects an analyzis of the interaction between experimental factors and years. Figures 2 and 3: No analysis of the relationship between grain yield and soil properties, as well as SQI.
Response 10 and 11: Thanks a lot for the comment. According to your comments, permit me to explain further. Soil quality is the result of the integration of soil physical, chemical and biological properties. In order to calculate SQI, we have to reduce the data redundancy between different indicators. Figure 2 and Figure 3 are all necessary redundancy analysis process, Figure 2 analyzed the correlation among 22 soil characteristics and figure 3 further analyzed the redundancy of soil physical structure with soil chemistry factors and soil enzyme activities under four tillage practices, the grain yield and SQI are irrelevant in the case. However, according to your comment, we realized it is very important to discuss the results of SQI and grain yield. The yield verifies the impact of soil quality, but there is a lack of integral data result in the present study. We added the relationship between yield and SQI as displayed in Table 6. Because precipitation is very important for wheat yield in the case, we also added the analysis of the interaction between tillage and precipitation during summer fallow on yield in Table 1 and Table 5. The revised discussion have be highlighted.
Comment 12: Only if points 8 and 9 are implemted can disscussions be carried out correctly. As it stands, this is just and extended discussion of the results.
Response 12: Points 10 and 11 have be implemted, and the revised discussion have be highlighted.
Yours sincerely,
Zhiqiang Gao
Shanxi Agricultural University
