Comparative Analysis of Pasture Soil Fertility in Semiarid Agro-Silvo-Pastoral Systems
, João M. Serrano 2, Francisco J. Rebollo 3, Ricardo F. M. Teixeira 4 and Tiago Domingos 4Round 1
Reviewer 1 Report
This is research is meaningful. But the format of the manuscript is not standardized. For example in" 2.2. Soil sample collection and analysis" part, 100m2 should be changed to 100m2, K2O is changed to K2O, CO2 is changed to CO2 . Author should check the whole text.
The reference is not standardized. In reference 19" J. Soil Sci. Plant. Nutr,"should be italic.
Author Response
All comments and suggestions has been addressed.
Reviewer 2 Report
The manuscript reports the application of Rasch model to categorise pasture soil fertility based on location and soil characteristics. I would like to congratulate the Authors for conducting the study and preparing the manuscript.
The manuscript has value to the scientific community, however, there are some concerns (mentioned below) that should be addressed to make the manuscript acceptable for publication.
It is well known that soil fertility is different within a large field. Several studies have been conducted and reported that there is a need to optimize management practices for better yields based on the variability within the field. The manuscript does not highlight clearly what is new in this study. It could be that a new element in this area is the application of the Rasch model in delineating pasture soil fertility. If this is the case then the Authors need to highlight the earlier usage of similar models as well, with their performances in the studies.
For the review process, it is better to have line numbers in the manuscript. It is easier to refer to specific lines or sections in the manuscript.
Abstract
Half of the abstract talks about the background and methods and less about the results, which prevents readers to understand the result of the study.
The results presented in the abstract are not direct and clear. It’s hard for the readers to have clear takeaway message from the study. At the very end, the authors have mentioned about “slope” and its influence on pasture soil fertility. Apart from that, no other soil property or characteristic is mentioned.
The last sentence “A better application of inputs, including a more cost-effective management of the fields, can be achieved if differences in pasture systems are considered.” is a very general statement. Similar sentences can be seen in many studies. Authors could be more direct and contextual based on their results.
I would suggest including some more results and putting that in contextual perspective.
Introduction
There are redundancies in the introduction in several places.
Information about the Rasch model and its application in this study is limited. The authors need to provide a bit more information about the model and the applications of earlier models in the subject area.
Some unclear sentences need correction or re-phrasing. For example,
“Many goods are produced in these systems, such as cork, firewood honey, etc., but they are mainly grazed by animals.” What does “they” mean in this sentence?
Material and methods.
There is enough explanation in the materials and methods section. However, in certain places that is not enough. For example:
Before formulating the Rasch model, it is necessary to categorise all data for achiev-ing an adimensional characterisation. Five categories were defined for all soil variables, as it was conducted in many previous studies [3,5,9]. Class 1 was assigned to the lowest contribution to soil fertility of each measure of a soil property and, on the contrary, class 5 was assigned to the highest contribution to soil fertility.
It would be good to mention what are those 5 categories that were used to define soil variables. The authors have provided the references but for a quick grasp those can be mentioned.
State what Infit and Outfit Mean-Square values suggest. There are acceptable values mentioned but what those values mean needs to be explained briefly. Same for ZSTD.
Larger positive values are com-puted for locations where pasture soil fertility is higher or soil properties with lower in-fluence on the pasture soil fertility. On the contrary, larger negative values are computed for those soil properties with higher influence on pasture soil fertility or locations where soil fertility is lower.
Larger positive values for locations indicate higher pasture soil fertility and larger negative values for soil properties indicate higher influence on pasture soil property. It is not very clear why there is a contradiction for pasture soil fertility in terms of measured values and raw score for locations (table 3) and soil properties (table 5).
Results:
The first step is the overall analysis of the data response to the Rasch model. Should it be “response of Rashc model to the data?
The reliability statistics were 0.79 and 0.93 for samples and items, respectively. What is the determinant? Infit or Outfit MNSQ or something else?
In-fit or Infit---consistency in the manuscript
Table 2: infit and outfit, each should have two columns. one for MNSQ and another for ZSTD.
There is an explanation that high clay content at Cubillos could be the possible explanation for high pasture fertility. But table 5 suggests clay content influence on pasture fertility is the lowest. If it’s correct. Please explain the possible reasons why there is a dichotomy between the role of locations and soil property for pasture soil fertility.
There is some explanation “In contrast, clay content has the lowest overall influence on soil fertility in these fields, with the lowest raw score (and the highest measure). Sand content has also a low influence on soil fertility. In consequence, as it could be expected, textural components are not globally important in these sandy fields to define the most fertile zones, except for those fields (Cubillos and Grous) where the clay content is higher”.
However, the answer to why clay content has a lower influence on fertility is not clear. It could be explained on the basis of raw score and measure computation. But it would be better if it can be explained based on field level observed characteristics.
There are some unclear statements. For example, “After analysing the misfits, i.e., sampling locations which do not follow the pattern of the model, it was found a low amount of them.
Considering all sampling locations of each field (Figure 4), sampling locations are aggregated only in Cubillos (they are at the right of the continuum in Figure 3), with a high fertility level….can the variability be seen based on Rasch measure? If not, authors should provide reasons with numbers on how and why sampling locations have more variability for soil fertility.
Did not understand:
Was there any difference between north and south locations, as there is a gradient from south to north for precipitation?
Table 3: It would be interesting to know, for example, why MUR 04, MUR 07, and MUR 09 have very different Raw scores and Measures. Probably the answer is in the Misfits or differences in the soil properties.
Conclusion:
The conclusion reads more like why the study was conducted and the possible usage of results but less on take-home messages based on the results in the study. It needs re-writing based on the direct results.
General comments:
Too wordy and complicated sentences and redundancy prevent readers to keep track.
Some sentences are too wordy. For example:
“These variable spatial patterns in many soil properties lead to an important spatial variability in soil fertility, which determines the existence of spatial variability in pasture yield and quality.”
Complicated and Redundant sentences:
Moreover, the spatial var-viability of soil nutrients is related to the spatial patterns of biomass yield [12]. Conse-quently, yield variability is related to variability on soil properties, because soil patterns determine plant available water and, in turn, pasture production potential [10].
Said above:
Pasture soil fertility and, in turn, pasture production potential are usually very different not only between fields but also within each field, so the economic feasibility of these silvo–pastoral ecosystems requires the implementation of strategies adapted to each particular field [13].
Author Response
Please, see the attached file
Author Response File: 
Author Response.pdf
Reviewer 3 Report
The manuscript addresses an important aspect of rational input application in fertility management using the Rasch model.
The manuscript needs improvement to the results section and discussion as well as the conclusions too. Please see comments in stickers on the pdf.
All tables 2 - 5 need revised titles that a short and informative. In their current form, they are very long and much of the information in tittles should be in the table captions, which are now missing.
The conclusions section is not a summary of the results and discussion/study findings but more like an addition to the introduction and methods.
Specific comments are provided in sticker comments on the pdf file.
Comments for author File: Comments.pdf
Author Response
All comments and suggestions has been addressed. Conclusions section has been rewritten and the specific comment addressed as indicated.
Round 2
Reviewer 2 Report
The authors have addressed some of the concerns that were raised in the earlier review process and made the changes accordingly. However, the paper is not yet acceptable for publishing in its current form based on the following reasoning.
1. The paper is not written clearly and it has not improved, in terms of clearty, from the last submission. A common reader has to go through several times to understand what the authors want to Convery.
2. There are many contradictory statements in the manuscript which creates more confusion. This also suggests that the authors did not write the manuscript in a synthesized way.
3. Their results raise many questions that are not answered in the paper.
There are some unclear or grammatical errors in the sentences.
Abstract:
Moreover, another output of the model was a ranking of the soil properties according to their influence on the soil fertility, being the topographical property, slope, the most influential because it influences the level of other important soil properties, as the textural components.
Two fields, Cubillos and Grous, had the highest soil fertility levels, and the soil samples in these fields were very fertile.
A better application of inputs (is it fertilizer that the authors are talking about or something else), including a more cost-effective management of the fields (is it machinery ..?), can be achieved if differences (is it pasture soil fertility..?) in pasture systems are considered
Introduction
“Moreover, in the current context of climate change, particularly marked in this region [8], the importance of an adequate management is essential for its conservation”
What does “marked” suggest here?
“The main factor that determines forage yield and quality (pasture productivity) is soil fertility, so the knowledge of variability of pasture soil fertility is essential to propose site-specific management strategies”
In my opinion forage yield and quality cannot be called “pasture productivity”.
Contradictory or unanswered statements:
Authors state that sand and clay contents vary between locations and have less influence on fertility. Then by stating that “In fact, the fertility level at each location in any field is related to the clay content because moisture and nutrient contents in locations with higher clay con-tent are also higher [5].” The authors contradict their own statement.
And when we read this:
“The rest of the fields have locations with high and low soil fertility, that is, their spatial variability is more important. This is related to the predominant soil texture in each field. The mean sand content in Cubillos and Grous is 37.5% and 57.6%, respectively, while it is higher than 70% in the other five fields. Moreover, the mean clay content in Cubillos is 23.5%, in Grous is 16.8%, and lower than 10% in the other fields [1314]. Some previous studies in agricultural fields where clay contents are higher, showed its influence on soil fertility [15,23,38].”
It appears that soil texture influence soil fertility. This again contradicts the above statements.
If slope is driving soil fertility and authors also say that “This is be-cause this topographical variable determines the level of other soil properties, for instance, the textural components” then why clay and sand is not influential on fertility? Should not they have to be closer raw score and measured value as slope?
Is the term misfit synonymous with outfit (which is described in M & M)?
“After analysing the misfits, i.e., sampling locations which do not follow the pattern of the model, it was found a low amount of them. This is another evidence (only 5 soil samples had at least one misfit, approximately 12% of the good agreement between the data and the model.samples). The sampling locations that displayed misfit are shown in Table 4. Only fiveTwo samples displayedhad two misfits and two of them had two mis-fits. When the residuals were positive, the score for the sample in those residuals was higher than expected. Negative residuals indicate that the score was lower than expected. Thus, the sample AZI01 has a low fertility (−1.08) but the organic matter content is too high and the score is, in turn, the maximum, 5. It was expected a lower organic matter content in this location. Unlike the previous sample, sampling location GRO11 has a high fertility (0.52) but the score is too low, 1. It would be expected a higher organic matter content in this location. Moreover, the expected slope was lower than the existing in this place. Similar explanations can be argued for the other misfits in each sample and soil property shown in Table 4.”
In this paragraph, the usage of the word “expected” creates a lot of confusion. Also, the way the reasoning of misfit (or Outfit) is explained is difficult to grasp.
For better readable quality, I strongly suggest that the paper should be read by a native English speaker. The way some sentences are written creates confusion rather than giving clear messages. The paper has merit, however, it needs clear and synthesized writing.
Author Response
See the attached file
Author Response File: 
Author Response.docx
Round 3
Reviewer 2 Report
Reviewer 2
Please find my responses below in blue font.
The authors have addressed some of the concerns that were raised in the earlier review process and made the changes accordingly. However, the paper is not yet acceptable for publishing in its current form based on the following reasoning.
1. The paper is not written clearly and it has not improved, in terms of clearty, from the last submission. A common reader has to go through several times to understand what the authors want to Convery.
2. There are many contradictory statements in the manuscript which creates more confusion. This also suggests that the authors did not write the manuscript in a synthesized way.
3. Their results raise many questions that are not answered in the paper.
There are some unclear or grammatical errors in the sentences.
Abstract:
Moreover, another output of the model was a ranking of the soil properties according to their influence on the soil fertility, being the topographical property, slope, the most influential because it influences the level of other important soil properties, as the textural components.
Two fields, Cubillos and Grous, had the highest soil fertility levels, and the soil samples in these fields were very fertile.
A better application of inputs (is it fertilizer that the authors are talking about or something else), including a more cost-effective management of the fields (is it machinery ..?), can be achieved if differences (is it pasture soil fertility..?) in pasture systems are considered
These sentences have been rewritten.
Introduction
“Moreover, in the current context of climate change, particularly marked in this region [8], the importance of an adequate management is essential for its conservation”
What does “marked” suggest here?
We have change the word “marked” by “intense”.
“The main factor that determines forage yield and quality (pasture productivity) is soil fertility, so the knowledge of variability of pasture soil fertility is essential to propose site-specific management strategies”
In my opinion forage yield and quality cannot be called “pasture productivity”.
It has been removed.
Contradictory or unanswered statements:
Authors state that sand and clay contents vary between locations and have less influence on fertility. Then by stating that “In fact, the fertility level at each location in any field is related to the clay content because moisture and nutrient contents in locations with higher clay con-tent are also higher [5].” The authors contradict their own statement.
And when we read this:
“The rest of the fields have locations with high and low soil fertility, that is, their spatial variability is more important. This is related to the predominant soil texture in each field. The mean sand content in Cubillos and Grous is 37.5% and 57.6%, respectively, while it is higher than 70% in the other five fields. Moreover, the mean clay content in Cubillos is 23.5%, in Grous is 16.8%, and lower than 10% in the other fields [1314]. Some previous studies in agricultural fields where clay contents are higher, showed its influence on soil fertility [15,23,38].”
It appears that soil texture influence soil fertility. This again contradicts the above statements.
It is important to differentiate between the overall pasture soil fertility, that is, considering each field as a unit, and the soil fertility at each sampling location. As the mean clay content in most of the fields is very low, its influence on the overall soil fertility considering the fields is also very low. It does not mean that at each particular sampling point, the clay content is not important. Conversely, it is very important when its level is not so low, as we have in some of the locations of the experimental fields.
This is not contradictory. It the real fact we usually have in our fields, where soil spatial variability is very important.
Thanks for clarifying. It makes sense now. Please replace the word "location" with "sampling location" as it is mentioned in several places in the text.
If slope is driving soil fertility and authors also say that “This is be-cause this topographical variable determines the level of other soil properties, for instance, the textural components” then why clay and sand is not influential on fertility? Should not they have to be closer raw score and measured value as slope?
This is also related to the overall or the particular soil fertility at each sampling location as it was aforementioned.
Is the term misfit synonymous with outfit (which is described in M & M)?
No, they are different concepts as it has been described in the text.
Thanks for clarifying. The first usage of the word “misfit” is in the results section with a reference. I would suggest adding a brief phrase about how this is different than “outfit”.
In the text, outfit is described as: “outlier-sensitive fit. It is more sensitive to responses to items that are far from the expected on the latent variable”
Misfits: sampling locations which do not follow the pattern of the model.
It sounds an outfit is a single computed value that is away from the “expected latent variable”, while a misfit is mostly about the dynamical change (in relative to…) a pattern?
“After analysing the misfits, i.e., sampling locations which do not follow the pattern of the model, it was found a low amount of them. This is another evidence (only 5 soil samples had at least one misfit, approximately 12% of the good agreement between the data and the model.samples). The sampling locations that displayed misfit are shown in Table 4. Only fiveTwo samples displayedhad two misfits and two of them had two mis-fits. When the residuals were positive, the score for the sample in those residuals was higher than expected. Negative residuals indicate that the score was lower than expected. Thus, the sample AZI01 has a low fertility (−1.08) but the organic matter content is too high and the score is, in turn, the maximum, 5. It was expected a lower organic matter content in this location. Unlike the previous sample, sampling location GRO11 has a high fertility (0.52) but the score is too low, 1. It would be expected a higher organic matter content in this location. Moreover, the expected slope was lower than the existing in this place. Similar explanations can be argued for the other misfits in each sample and soil property shown in Table 4.”
In this paragraph, the usage of the word “expected” creates a lot of confusion. Also, the way the reasoning of misfit (or Outfit) is explained is difficult to grasp.
I desagree with this statement. They are words usually used in this kind of statistical explanations. The meaning of misfit is explained at the beginning of the paragraph.
Okay
For better readable quality, I strongly suggest that the paper should be read by a native English speaker. The way some sentences are written creates confusion rather than giving clear messages. The paper has merit, however, it needs clear and synthesized writing.
The manuscript has been read by two colleagues who are native English speakers and both have a scientific background.
Okay
It is always great to see all the changes that were made in the text in the response letter with the changed texts. Reviewing becomes difficult in this no-line number format of the submission.
Author Response
Please, see the attached file.
Author Response File: Author Response.pdf
