Soil Cover Improves Soil Quality in a Young Walnut Forest in the Sichuan Basin, China
, Josep Peñuelas 3,4, Jordi Sardans 3,4, Wenyu Bai 1,2, Dongmiao Han 1,2,5, Tao Wu 1,2 and Wenbing Li 1,2,6Round 1
Reviewer 1 Report
The article topic is interesting.
There are several points to note concerning that need some substantial and detailed improvement regarding the following:
- Overview:
The review is complete, and it cites the most relevant information in this area; the authors made a comprehensive revision about the background of the soil covers. However, white film (WF), black film (BF), shade netting (SN), and maize straw (MS) covers require more information to let the readers understand the whole concept. Finally, the authors should include the soil health concept in the review.
- Methods
In Line 124 – 126 should include the description on white film
- Results:
The main outcomes are well presented but there are some concerns of the text in Lines 239 and 246. This chunk has to be rewritten.
In the Discussion Section, the authors compare different soil layer deep. It increases the uncertainties of the results, be aware of comparing similar setups. e.g. Lines 369 – 370.
- Conclusions
The authors have included the pros, but not the cons of these soil covers.
Author Response
#1. Overview: The review is complete, and it cites the most relevant information in this area; the authors made a comprehensive revision about the background of the soil covers. However, white film (WF), black film (BF), shade netting (SN), and maize straw (MS) covers require more information to let the readers understand the whole concept. Finally, the authors should include the soil health concept in the review.
Response: First, we now have further clarified that the treatments were covered onto the soil surface. We also added more information about them, e.g., “The white and black films comprised 0.01 mm thick biodegradable polyethylene; white film shading rate was approximately 15%; black film shading rate was approximately 95%” (in chapter of 2.2.2. Plot design). Second, the revised manuscript now included soil health in the Introduction, i.e., “Soil quality, also known as soil health, is defined as the functional capacity of soil within an ecosystem or land-use boundary to sustain biological productivity, maintain environmental quality, and promote plant and animal health” (in chapter of 1. Introduction).
#2. Methods: In Line 124 – 126 should include the description on white film
Response: Yes, we now have descripted the white film. It now reads “The white and black films comprised 0.01 mm thick biodegradable polyethylene; .... The white and black films were replaced with new ones in December 2013 and October 2014” (in chapter of 2.2.2. Plot design).
#3. Results: The main outcomes are well presented but there are some concerns of the text in Lines 239 and 246. This chunk has to be rewritten.
Response: We now have corrected this part to now read “During the study period, the soil fauna mainly gathered in the 5–15 cm soil layer in CK (78.2%; Figure 4a) and in the 0–10 cm soil layer in soils covered with WF, BF, and MS (75.8, 77.3, and 81.1%, respectively). The fauna in the soils covered with SN was found in 33.8, 35.9, and 30.3% in the 0–5, 5–10, and 10–15 cm soil layers, respectively. The vertical distribution of soil fauna was different in different sampling months (Figure 4b–f).” (in chapter of 3.2. Effect of soil cover on soil fauna).
#4. In the Discussion Section, the authors compare different soil layer deep. It increases the uncertainties of the results, be aware of comparing similar setups. e.g. Lines 369 – 370.
Response: Thank you for calling this issue to our attention. We have now added the possible conclusions of this result, reading “In summary, soil cover types overall increased the soil faunal diversity in 0-15 cm soil layer, but the impacts differed among 0-5, 5-10, and 10-15 cm layers.” (in chapter of 4.2. Soil cover increased soil MBC and faunal diversity). Moreover, we now have highlighted that this study was conducted in the 0-15 cm soil layer. For, example, “We investigated the effects of white film (WF), black film (BF), shade netting (SN), and maize straw (MS) soil cover types and an uncovered control type (CK) on soil chemical and biological indicators and the SQI in the 0-15 cm soil layer in a young walnut forest in the Sichuan Basin over a 27-month study period.” (in the Abstract), “In this study, we carried out a 27-month experiment in the region to examine the effects of soil cover on soil nutrient concentrations, microbial biomass carbon (MBC), the number of soil fauna groups (N) and individuals (S), and the SQI in the 0-15 cm soil layer.” (in chapter of 1. Introduction), and “The results highlighted that SOM, TN, AK, S, and MBC were the minimum required soil variables for the effective assessment of the SQI in the 0-15 cm soil layer in the studied young walnut forest.” (in chapter of 5. Conclusions).
#5. Conclusions: The authors have included the pros, but not the cons of these soil covers.
Response: We now have added the following description in the revised version, i.e., “Soil cover types affected the vertical distribution of soil fauna, so the impacts among 0-5, 5-10, and 10-15 cm may be different.” (in chapter of 5. Conclusions).
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear Authors
After reading your manuscript entitled: "Soil cover improves soil quality in a young walnut forest in the Sichuan Basin, China" several times, I added my comments as follow:
This study explained the effect of different soil cover amendments on soil quality in a young walnut forest. The authors showed soil cover impacted soil quality, emphasizing maize straw cover as the best option for this forest. The manuscript is well written and straightforward in each section. The results are impressive and well discussed. Some minor comments were added to improve the quality. Please see the attached file.
Comments for author File: 
Comments.pdf
Author Response
#1. After reading your manuscript entitled: "Soil cover improves soil quality in a young walnut forest in the Sichuan Basin, China" several times, I added my comments as follow: This study explained the effect of different soil cover amendments on soil quality in a young walnut forest. The authors showed soil cover impacted soil quality, emphasizing maize straw cover as the best option for this forest. The manuscript is well written and straightforward in each section. The results are impressive and well discussed. Some minor comments were added to improve the quality. Please see the attached file.
Response: Thank you very much for your approval and positive consideration of this manuscript. We now have corrected the manuscript according to your comments. The main corrections are as follows.
First, we now have used similarly expression for the soil cover treatments. E.g., “We investigated the effects of white film (WF), black film (BF), shade netting (SN), and maize straw (MS) soil cover types and an uncovered control type (CK)…”(in Abstract). Moreover, we have changed the “uncovered soils” with “CK” in the revised version.
Second, we have moved the Figure S1 to the revised manuscript as Figure 1. We have also corrected the order of the figures in the text.
Third, we have added the soil bulk density: “…a soil bulk density of 1.73 ± 0.35 g-1 cm-3 at the beginning of this experiment.” (in section 2.1. Study site).
Fourth, we have divided “Moss and leaf litter were removed from the soil surface, and five samples of the 0–15 cm soil layer were collected at random from each plot (avoiding the fertilized area around the base of the saplings) using a 5-cm diameter soil auger [27,28] and then mixed to form a single composite sample.” into two sentences, i.e., “Before soil sampling, moss and leaf litter were removed from the soil surface. Five samples of the 0–15 cm soil layer were collected at random from each plot (avoiding the fertilized area around the base of the saplings) using a 5-cm diameter soil auger [1,2] and then mixed to form a single composite sample.” (in chapter of 2.3.1. Soil chemical indicators and MBC).
Fifth, we have defined the arrows in the Figure 5. It reads “Blue and red arrows indicate biological and environmental variables, respectively.” (in chapter of 3.5. Relationships between soil biological indicators and soil chemical indicators).
Sixth, we have changed “soil texture” with “soil types” in the Discussion. (in chapter of 4.1. Soil cover altered soil nutrient concentrations).
Seventh, we have changed “Ctr” with “CK” in Figure 1 and 4 in the revised manuscript.
Two native English experts have corrected the files and improved the logic in the revised manuscript. We believe that the quality of the revised manuscript has been improved substantially thanks to the insightful suggestions of the referees and the editor. We sincerely appreciate your help and consideration.
Author Response File: Author Response.docx
