Comparison of the Effects of Different Crop Production Systems on Soil Physico-Chemical Properties and Microbial Activity under Winter Wheat
Round 1
Reviewer 1 Report
Review Agronomy-862290
The authors did a conventional study on the consequences of conservation tillage practices for various soil quality indicators in long term cropped and grassland systems. They observed pretty much what previous work in this field has reported. From that perspective, although the research was thoughtfully conducted and analyzed, there is nothing particularly new or novel in the approach and observations. In comparing dehydrogenase activity/extractable C ratios the authors seem to be presenting a potential new index to use in evaluating soil quality, but they never really do much with this topic.
The work, as presented, is difficult to read. Any manuscript that requires 132 references and isn’t a review is clearly over-referenced. Because the topic is so well studied, the authors spend far too much time throughout in detailing background information and procedural details that are well understood. In essence they suggest they have three treatments. In reality, the permanent grass is a control and would be best used as a standard against which to compare the organic and conventional treatments. That approach itself has limitations because the cropping system in each of the cropping systems differed. So, various statements about the consequences of the organic matter addition and microbial response are tenuous because the systems are strikingly different in crop input, which is consequential. It is not clear how widely distributed the samples were in each field. It must be made obvious that sufficient distance existed between sample points to reflect site heterogeneity or the study design can simply be regarded as pseudoreplication.
Specific Comments
The abstract lacks a rationale statement and the introduction lacks a hypothesis and an indication of what is unique about the study.
Keywords should not repeat what is already present in the title
The first sentence of the introduction is both long and not very readable
- 43-104 Contain a tremendous amount of background information that is very basic and unnecessary. It should be pruned vigorously to highlight the supposed knowledge gaps your research addresses.
- 150 What’s your hypothesis? Because an observational study like this doesn’t break new ground. Incomparing conventional vs. organic relative to a control (grass) are you suggesting there are specific changes best revealed by the parametes you chose?
Table 1 is not needed. Is it really worth noting that over this period texture did not change? Would you expect it to?
- 172-173 How can you compare your systems if they have so many constantly changing variables?
- 203 What was the separation distance of sampling for replication?
Table 4 and 5 would best be presented as figures because the goal is simply to reveal any underlying trends in temperature and precipitation that might explain year-to-year differences in response.
The methods are standard, so they do not need so much detail.
- 331 ff If not significant, why so much detailed analysis?
- 358 This is rather obvious based on the equation that was used for the calculation.
Figure 2. Fundamentally, given the equation you used, you need either the bulk density or the total porosity to make your point about structural effects, not both. I prefer total porosity.
- 388 This is not a very enlightening observation.
- 402-404 There is little novelty in this observation.
- 410-414 Or did not lose as much SOM with time. Your analysis does not really distinguish this.
- 429-430 This hardly needs stating. When does tillage increase SOM?
- 468-472 You must focus more on what you have found that is new.
- 508-510 This does not appear to be a reasonable explanation to me.
- 522-523 Or crop. So this is a tenuous statement. The nature and amount of crop residues in each system differs, unless you consider crop used as part of soil management
- 644-645. This might be one of your more novel analyses. But how does it compare to other assessments of metabolic activity in soil quality assessment. You can do much more here as part of the discussion.
Author Response
Puławy, Poland, July 21st, 2020
Response letter to Reviewers’ and Editor’s
Dear Editor,
Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Effects of Different Land Use and Management Practices (Organic and Conventional Crop Production vs Permanent Grass) on Soil Physico-Chemical Properties and Microbial Activity”. The title has been shortened according to the Editor’s suggestion to “Comparison of the Effects of Different Crop Production Systems on Soil Physico-Chemical Properties and Microbial Activity under Winter Wheat”. These comments have been valuable and helpful for revising and improving our paper. We have studied your comments carefully and have made corrections which we hope meet with your approval. Revised portions are marked using the ‘Track Changes’ function in Microsoft Word. The main corrections in the paper and our responses to the Editor’s and Reviewers’ comments are as follows:
Reviewer(s)' Comments to Author:
Reviewer: 1
Comments to the Author
The authors did a conventional study on the consequences of conservation tillage practices for various soil quality indicators in long term cropped and grassland systems. They observed pretty much what previous work in this field has reported. From that perspective, although the research was thoughtfully conducted and analyzed, there is nothing particularly new or novel in the approach and observations. In comparing dehydrogenase activity/extractable C ratios the authors seem to be presenting a potential new index to use in evaluating soil quality, but they never really do much with this topic.
The work, as presented, is difficult to read. Any manuscript that requires 132 references and isn’t a review is clearly over-referenced. Because the topic is so well studied, the authors spend far too much time throughout in detailing background information and procedural details that are well understood. In essence they suggest they have three treatments. In reality, the permanent grass is a control and would be best used as a standard against which to compare the organic and conventional treatments. That approach itself has limitations because the cropping system in each of the cropping systems differed. So, various statements about the consequences of the organic matter addition and microbial response are tenuous because the systems are strikingly different in crop input, which is consequential. It is not clear how widely distributed the samples were in each field. It must be made obvious that sufficient distance existed between sample points to reflect site heterogeneity or the study design can simply be regarded as pseudoreplication.
Specific Comments
Response letter to Reviewer #1’s comments:
Comment: The abstract lacks a rationale statement and the introduction lacks a hypothesis and an indication of what is unique about the study.
Reply to comment: Yes, I agree. I add all missing sentences as below:
Abstact: L15 In many areas, organic crop production systems have been shown to contribute to maintaining good soil properties. The organic production system has been recommended as an alternative to conventional agriculture. However, in order to recommend this practice in new regions, it is necessary to obtain information about its effects and consequences in local environmental conditions.
Introduction: L145 The propose of this paper is to test the following hypoteses:1. there will be an improvement in OM and some its fractions and consequently improvement in some properties of tilled soil under an organic crop production system and/or non-tilled soil under permanent grass; 2. there will be a decrease in OM and some its fractions and consequently deterioration some properties in tilled soil under a conventional crop production system.
An explanation, what is unique about the study – see below:
The content of organic matter has been steadily decreasing in agricultural soils in Poland and in Europe more generally. Therefore, the agricultural sector has received the additional task of protecting the organic matter resources in soil while maintaining the current level of crop production, and that was the main reason why this research was done.
It should be emphasized that these studies were conducted on a long-term field experiment, in which winter wheat was grown in the studied crop production systems for 26 years.
In this paper, we present the research on biological and physico-chemical soil properties, which appeared to be highly correlated between each other. In addition, the analysis of changes in soil biological activity were made at the same time as monitoring of the physical and chemical properties of soil (soil sampling time, sampling position on the field), which is valuable and helpful in assessing soil quality.
Greater activity of soil microbial communities in a Haplic Luvisol soil was found under an organic crop production system compared with conventional. This activity was measured with dehydrogenases. Also, higher concentrations of OM and its labile fractions were observed in soil under the organic system, in particular in the 0 - 5 cm depth layer in comparison with the conventional system.
In our study, the effects of various crop production systems on the soil environment were analysed using mostly conventional analytical parameters. This helped us to assess the differences in the soil properties changes caused by different production systems.
So far, no parameter has been defined that could be regarded as a universal biological indicator of soil quality. Therefore, assessment of soil based on the analysis of the values of many parameters is more appropriate. The basic problem associated with soil biomonitoring is the natural variability of most of the analysed parameters. A certain solution in this case can be offered by some proposed indicators.
To get a better picture of the soil environmental changes for the first time in our study the metabolic potential index (MPI) was tested. The metabolic potential index was originally proposed by Masciandaro et al. (1998) as a ratio of dehydrogenases activity to the content of soluble organic carbon. Due to lack of information in the literature we wanted to test this new index and check its usefulness in assessing the quality of our soils.
The metabolic index appeared to be very helpful in evaluation of the effects of different crop production systems on soil quality. In soil under intensive agronomic use as in the conventional crop production system, MPI reached lower values compared to non-tilled soil and/or soil under the organic crop production system. The non–tilled soil under permanent grass was used as a control to better see the scale of changes in soil induced by agronomic practice.
Further work should extend this approach to the wider scale dataset in the soil information system.
Comment: Keywords should not repeat what is already present in the tittle
Reply to comment: Yes, I agree. I changed the tittle as the Editor suggested and Keywords do not repeat words with what is already present in the tittle.
Comment: The first sentence of the introduction is both long and not very readable
Reply to comment: Thank you very much. I agree. Indeed, the sentence is difficult to read.
I correct the sentence as below:
L40. The decline in soil fertility observed in recent decades is indicative of the effects of continued use of intensive tillage. Moreover, insufficient use of agricultural practices to sustain good soil quality can exacerbate this problem [1,2].
Comments: L43-104 Contain a tremendous amount of background information that is very basic and unnecessary. It should be pruned vigorously to highlight the supposed knowledge gaps your research addresses.
Reply to comments: Thank you very much. I agree. I made some corrections and reduced the text as much as possible. L50-57; L70-78; L91-106.
Comments: L150 What’s your hypothesis? Because an observational study like this doesn’t break new ground. Incomparing conventional vs. organic relative to a control (grass) are you suggesting there are specific changes best revealed by the parametes you chose?
Reply to comments: Thank you very much. I agree. Hypotheses were added.
L145. The propose of this paper is to test the following hypoteses:1. there will be an improvement in OM and some its fractions and consequently improvement in some properties of tilled soil under an organic crop production system and/or non-tilled soil under permanent grass; 2. there will be a decrease in OM and some its fractions and consequently deterioration some properties in tilled soil under a conventional crop production system.
Comment: Table 1 is not needed. Is it really worth noting that over this period texture did not change? Would you expect it to?
Reply to comment: Thank you very much. I agree. Indeed, but Table 1 is informative only to show that all treatments were placed on the same soil texture and soil samples taken for analysis from our experimental fields were of the same texture. L160Table 1 was removed.
Comments: L172-173 How can you compare your systems if they have so many constantly changing variables?
Reply to comments: Thank you very much. I agree. The experiment was established in 1994 on experimental fields with different crop production systems. More information is given in [7,66,68] (new numbers 7,39,40). In the period 2016-2018 we compared the effects of long-term tilled soil under winter wheat grown in organic and conventional crop production systems with non-tilled soil under permanent grass as a control.
Comments: L203 What was the separation distance of sampling for replication?
Reply to comments: It is extremely important. I add an explanation:
L203 Each sample point we considered as a replicate because the field experiment was established without replications due to physical constraints such as land availability or plot size. Sample points within each treatment were far enough from each other (20 m) to ensure the replicate independence. To avoid the edge effect the sampling points were placed at least 5 meters from the field margin. The locations of sampling points were chosen carefully to avoid the soil heterogeneity using existing soil maps. The site topography of was taken also into consideration.
Comments: Table 4 and 5 would best be presented as figures because the goal is simply to reveal any underlying trends in temperature and precipitation that might explain year-to-year differences in response.
Reply to comments: I looked into the possibility to show data with graphs but this did not make it clearer. I wish to leave it as tables 4 and 5 (new numbers after the text revision table 3 and 4).
Comments: The methods are standard, so they do not need so much detail.
Reply to comments: I agree. According to suggestions I removed some details in the description of the methods. L233-239; L271-283.
Comments: L331 If not significant, why so much detailed analysis?
Reply to comments: Yes, I agree, I removed some details from the text.
Comments: L358 This is rather obvious based on the equation that was used for the calculation.
Reply to comments: I agree. The description of BD results were removed from the text L316-358.
Comments: Figure 2. Fundamentally, given the equation you used, you need either the bulk density or the total porosity to make your point about structural effects, not both. I prefer total porosity.
Reply to comments: I agree with suggestion. The data considering total porosity are left (new number - Figure 1).
Comments: L388 This is not a very enlightening observation.
Reply to comments: Yes, I agree. The sentence was removed L386-388.
Comments: L402-404 There is little novelty in this observation.
Reply to comments: Yes, I agree, the sentence was removed from the text.
Comments: L410-414 Or did not lose as much SOM with time. Your analysis does not really distinguish this.
Reply to comments: Yes, I agree, and according to suggestions we corrected Figure 3 (new number Figure 2) and this part of the text as below:
L411-420 we removed part of the text
The highest OM quantity 19.6 g kg-1 of soil was found in the top layer at 0-5 cm in non-tilled PRG soil. The results indicated that non-tilled soil under PRG increased significantly the OM content by 32% mostly at the 0-5 cm depth as compared with CON crop production system. Also, quite high the OM content (17.0 g kg-1 of soil) was measured in that soil at the 5-10 cm depth, but in relation to CON system the increase of OM content reached 13.0%.
The tilled soil under ORG crop production system showed similar trends in OM contents as non-tilled soil under PRG. The significantly higher OM concentration (18.0 g kg-1 of soil) was measured in soil under ORG system at the 0-5 cm depth, which was 26% more compared with CON system. At depths of 5-10 cm the OM content was significantly higher in soil under ORG system and PRG compared with CON system, similarly as the top layer.
I add new text: L411 The tilled soil under ORG crop production system showed similar trends in OM contents as non-tilled soil under PRG. At depths of 0-5 and 5-10 cm the OM content in soil under ORG system and PRG was significantly higher compared with CON system, however no significant differences were found between ORG and PRG treatments.
In the lower layer 15-20 cm the OM content dropped significantly in soil under PRG and ORG system in relation to 0-5 and 5-10 cm depths, but in CON system no significant differences were noticed. At the 30-35 cm depth significantly lower the OM contents were measured in soil under all studied treatments (Figure 2).
Comments: L429-430 This hardly needs stating. When does tillage increase SOM?
Reply to comments: Yes, I agree, and according to suggestions I removed part of the text as below:
The above findings are similar to the results published by many researchers, including [7,36,68,89] who found that organic management significantly increased OM concentration in surface soil compared with conventional farming system. L426-429 This can be explained by the fact that OM losses caused by tillage can be balanced by plant residue inputs as manure, green manure, compost, and crop components in the crop rotations, which are generally greater in organic than in conventional farming system. Also, Sarkar et al. [100] reported that OM concentration in soil within cultivated fields was significantly lower than within uncultivated fields and the decrease of OM was mainly due to the tillage practices.
Comments: L468-472 You must focus more on what you have found that is new.
Reply to comments: I agree. I reanalysed our data and the text relating to Figure 5 (new numer Figure 4) was added. Please, see below.
L469 The most beneficial effects on increase of POM percentage in total OM were observed in soil under PRG and ORG system, especially at the 0-5 cm depth. The contribution of POM fraction in the total content of OM decreased significantly in lower soil layers, especially in non-tilled PRG soil and tilled soil under ORG system contrary to CON system. High OM content in soil increased the percentage of labile POM fraction in total OM under PRG and ORG system compared to lower OM concentration under CON system.
Comments: L508-510 This does not appear to be a reasonable explanation to me.
Reply to comments: I agree. I removed the offending sentence with not quite reasonable explanation.
Comments: L522-523 Or crop. So this is a tenuous statement. The nature and amount of crop residues in each system differs, unless you consider crop used as part of soil management
Reply to comments: I agree. I would like to explain that we consider crop used as part of soil management too. The soil samples were taken for analysis at experimental fields under winter wheat only. Please, see corrected sentence below:
L522-524 It means that in this case the crop production systems significantly affect the transformation of OM mainly at top individual depth levels (humus).
Comments: L644-645. This might be one of your more novel analyses. But how does it compare to other assessments of metabolic activity in soil quality assessment. You can do much more here as part of the discussion.
Reply to comments: Yes, I agree. I add to the text this part below: L646.
So far, no parameter has been defined that could be regarded as a universal biological indicator of soil quality [Doran et al. 1996]. Therefore, assessment of soil based on the analysis of the values of many parameters is more appropriate. The basic problem associated with soil biomonitoring is the natural variability of most of the analysed parameters. A certain solution in this case can be offered by some proposed indicators.
To get a better picture of the soil environment changes for the first time in our study the metabolic potential index (MPI) was tested. Due to lack of information in the literature we wanted to check its usefulness in assessing the quality of our soils. The MPI appeared to be very helpful in evaluating effects of different crop production systems on soil quality. In soil under intensive agronomic use as in the conventional crop production system MPI reached lower values compared to non-tilled soil and/or soil under organic crop production system. The non–tilled soil under permanent grass was used as a control to better see the scale of changes in soil induced by agronomic practice.
Future work should extend this approach to the wider scale dataset in the soil information system.
We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper.
We appreciate the Editor’s and Reviewers’ work, and hope that the corrections will meet with approval.
Once again, thank you very much for your comments and suggestions.
Yours sincerely,
Anna Gajda and Co-Authors.
Reviewer 2 Report
Dear authors,
I am sorry but I have to say sorry that I cannot support the publication of your manuscript. The authors tried to clarify the impact of land use on soil properties, especially regarding to carbon. I noticed that the authors made great effort to collect data set of soil properties. However, the topic is not new, and many researchers already reported the similar kind of researches. In addition, most importantly, the experimental design was not well controlled: The authors prepared three types of treatment, but too many factors are different among the three, and it is hard to determine what caused the results. In other words, (1) planted vegetation, (2) tillages, (3) fertilization types, (4) fungicides, were different among the treatments, all of which could have affected the results, but we cannot determine. Several sentences, such as line 26 or 136, should be constructed again, because they are strange.Author Response
Puławy, Poland, July 21st, 2020
Response letter to Reviewers’ and Editor’s
Dear Editor,
Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Effects of Different Land Use and Management Practices (Organic and Conventional Crop Production vs Permanent Grass) on Soil Physico-Chemical Properties and Microbial Activity”. The title has been shortened according to the Editor’s suggestion to “Comparison of the Effects of Different Crop Production Systems on Soil Physico-Chemical Properties and Microbial Activity under Winter Wheat”. These comments have been valuable and helpful for revising and improving our paper. We have studied your comments carefully and have made corrections which we hope meet with your approval. Revised portions are marked using the ‘Track Changes’ function in Microsoft Word. The main corrections in the paper and our responses to the Editor’s and Reviewers’ comments are as follows:
Reviewer(s)' Comments to Author:
Comments to the Author
I am sorry but I have to say sorry that I cannot support the publication of your manuscript. The authors tried to clarify the impact of land use on soil properties, especially regarding to carbon. I noticed that the authors made great effort to collect data set of soil properties. However, the topic is not new, and many researchers already reported the similar kind of researches. In addition, most importantly, the experimental design was not well controlled: The authors prepared three types of treatment, but too many factors are different among the three, and it is hard to determine what caused the results. In other words, (1) planted vegetation, (2) tillages, (3) fertilization types, (4) fungicides, were different among the treatments, all of which could have affected the results, but we cannot determine. Several sentences, such as line 26 or 136, should be constructed again, because they are strange.
Response letter to Reviewer #2’s comments:
The content of organic matter has been steadily decreasing in agricultural soils in Poland and in Europe more generally. Therefore, the agricultural sector has received the additional task of protecting the organic matter resources in soil while maintaining the current level of crop production, and that was the main reason why this research was done.
The issue of maintaining the resources of organic matter in soils, especially agricultural ones, is still relevant and important in the context of the production potential of soils and the protection of its function in the environment.
It should be emphasized that these studies were conducted on the basis of long-term field experiments, in which the winter wheat was grown in the studied crop production systems for 26 years.
In addition, the analysis of changes in soil biological activity were made at the same time as monitoring of the physical and chemical properties of soil (soil sampling time, sampling position on the field), which is valuable and helpful in assessing soil quality. The non–tilled soil under permanent grass was used as a control to better see the scale of changes in soil induced by crop production systems.
We agree that the first version of our paper was difficult to read. According to the suggestions of the Editor and the Reviewers we have made major revisions as shown below:
1-the title has been shortened to: Comparison of the Effects of Different Crop Production Systems on Soil Physico-Chemical Properties and Microbial Activity under Winter Wheat;
2- the abstract was changed;
3-hypotheses were added;
4- significant amounts of text have been cut;
5- an explanation: the influence of too many factors to control we reduced by focussing only on fields under the same crop (winter wheat) in each crop production system;
The tillage treatment remained the same for each experimental field (1 ha each) since the beginning of the experiment.
There is no unique reference parameter that could be used to assess soil quality in the field where the effects of many factors influence the outcome. Therefore, several parameters were analysed to see and compare their trends so that we could have more clarity in assessing soil changes.
Sampling points within each treatment were far enough from each other (20 m) to ensure replicate independence. To avoid the edge effect the sampling points were placed 5 meters from the field margin at least. The locations of sampling points were chosen carefully to avoid the soil heterogeneity using existing soil maps. The site topography was taken also into consideration.
6- the new aspect (metabolic potential index) in evaluation of the effects of different crop production systems and permanent grass on soil quality has been emphasised;
To get a better picture of the soil environment changes for the first time in our study the metabolic potential index (MPI) was tested. The metabolic potential index was originally proposed by Masciandaro et al. (1998) as a ratio of dehydrogenases activity to the content of soluble organic carbon. Due to insufficient information in the literature we wanted to test this new index and check its usefulness in assessing the quality of our soils.
The metabolic index appeared to be very helpful in evaluation of the effects of different crop production systems on soil quality. In soil under intensive agronomic use as conventional crop production system MPI reached lower values compared to non-tilled soil and/or soil under organic crop production system. The non–tilled soil under permanent grass was used as a control to better see the scale of changes in soil induced by agronomic practice.
6- the Reference List was significantly reduced from 132 to 81
7- the sentences L26 and L136 were corrected.
We tried our best to improve the manuscript and made some changes in the manuscript. These changes will not influence the content and framework of the paper.
We appreciate the Editor’s and Reviewers’ work, and hope that the corrections will meet with approval.
Once again, thank you very much for your comments and suggestions.
Yours sincerely,
Anna Gajda and Co-Authors.
Round 2
Reviewer 1 Report
Good to go with a few more minor editorial corrections to the text in the proofing process. My comments have been addressed.
Author Response
Thank you very much for your review and for your effort to help us significantly improve our manuscript.
Best regards,
Anna Gajda and Co-authors
Reviewer 2 Report
The manuscript lacks the novelty, as I previously commented.
Author Response
Thank you very much for your review and for your effort to help us significantly improve our manuscript.
Best regards,
Anna Gajda and Co-authors
