Response of Biochemical Properties in Agricultural Soils Polluted with 4-Chloro-2-methylphenoxyacetic Acid (MCPA) under Severe Drought Conditions
, Marina del Toro 1, Patricia Paneque 1, Isidoro Gómez 1, Juan Parrado 2 and Concepción Benítez 3Round 1
Reviewer 1 Report
Interesting article, however, needs some additions:
1. is the study one year or three years? It is difficult to draw appropriate conclusions based on one-year studies.
2. The methodology states that the research was conducted in the laboratory, in pots. This is an experiment rightly conducted, however, here we have the absence of certain factors that will occur under field conditions. Maybe comparative studies in the future.
3. In the methodology it is stated that measurements were made after 3, 7, 15, 25, 35, 45, 60, 75 days. In contrast, in Tables 2, 3, 4, 5 we have after days 5, 15, 25, 35, 45, 60, 75 - there are some discrepancies here with the methodology. This needs to be corrected.
4. In Figure 1, the X axis should have the same designation for variants a, b and c. In the figure above, there are different markings for the X axis.
5. Chapter 5 needs to be rewritten for conclusions.
Author Response
- is the study one year or three years? It is difficult to draw appropriate conclusions based on one-year studies.
The study was done for 75 days. It is true that it is difficult to obtain reliable and conclusive conclusions in short-term studies, but we think that with this study we can obtain an important idea of how the experimental herbicide behaves in said short period of time after its application in different soils with different physicochemical characteristics. and different moisture conditions.
In addition, the reason for doing the experiment for 75 days is a consequence of the variability of the half-life of this herbicide in the soil, where it has been shown that it can range from a few days to a few months. This variability depends on many factors such as soil characteristics, temperature, humidity, biochemical activity of the soil, etc.
On the other hand, it should be noted that in our experiment the soil mcpa half-life was less than 75 days.
For this reason, the working group decided to carry out the study for 75 days.
- The methodology states that the research was conducted in the laboratory, in pots. This is an experiment rightly conducted, however, here we have the absence of certain factors that will occur under field conditions. Maybe comparative studies in the future.
The experimental study was carried out in pots in the laboratory so that we can control the drying of the soil. External weather conditions do not guarantee that for 75 consecutive days there will not be some type of natural rainfall.
For this reason, we decided to carry out the experiment in pots, as other authors have done according to the bibliography consulted.
- In the methodology it is stated that measurements were made after 3, 7, 15, 25, 35, 45, 60, 75 days. In contrast, in Tables 2, 3, 4, 5 we have after days 5, 15, 25, 35, 45, 60, 75 - there are some discrepancies here with the methodology. This needs to be corrected.
Reviewed. It was in error at the time of writing.
- In Figure 1, the X axis should have the same designation for variants a, b and c. In the figure above, there are different markings for the X axis.
First of all, we want to highlight that there was an error when defining each Figure.
Figure 1 shows the evolution of the herbicide in each experimental soil for the studied moisture conditions.
In this case the x-axes for each experimental soil (A, B and C) are different due to the MCPA half-life in each experimental soil.
On the other hand, we have revised the title of the following Figure, being Figure 2.
- Chapter 5 needs to be rewritten for conclusions.
We have revised this section as you have suggested. We believe that we highlight the final conclusions of the experiment carried out.
Reviewer 2 Report
This article deals with the possible effect of climate change, and of a decrease in soil water content, on the degradability and persistence of pesticides. In detail the study is carried out on MCPA and the impact of this herbicide for the control of dicotyledonous herbs in olive oil crops under drought conditions on soil biology.
The paper fits with the aims of the journal, despite the study is of local significance; the article is acceptable for publication.
Some modification could improve the quality of the overall work
I suggest in the introduction to give more information on the use, doses and economic impact of MCPA in the olive tree and in other crops on which it is registered; improve the conclusions which at the moment are too synthetic and specify whether the resultsare also valid for other crops on which MCPA is registered or if they are specific for olive trees
Better highlight how the effectiveness of the treatment can be influenced by environmental conditions
Author Response
The reviewer indicates that the manuscript is of local significance. The authors respect your comment but we do not share it.
MCPA is a herbicide used worldwide and therefore, as with other herbicides, its behavior is very different depending on the physicochemical characteristics of the soil as well as the soil's moisture status. Therefore we think it has an international character.
Regarding the reviewer's suggestions, we have included in the Introduction section more information about its use, generally highlighting the application rates as well as what other crops the herbicide is usually applied to.
We apply the dose of 2.4 l/ha according to the instructions of the manufacturer of the purchased commercial product. this is discussed in the Material and Methods section.
On the other hand, the reviewer suggests that we specify whether the results are also valid for other crops for which MCPA is registered or if they are specific to the olive tree.
At this point, the authors want to emphasize that in this manuscript the effect of the herbicide on the olive tree is not being studied. We emphasize that we try to study the behavior of this herbicide which is widely used in olive trees.
The objective of the manuscript is to observe the behavior of MCPA in 3 agricultural soils with different physicochemical properties in two moisture conditions (watered and non-watered soils).
On the other hand, the authors do not understand your suggestion regarding the "treatment" term. In the manuscript it is highlighted that both the different soils physicochemical characteristics and the moisture conditions influence in different ways the biochemical activity of the soil and, consequently, the herbicide degradation.
Reviewer 3 Report
This paper mainly evaluated the effects of different irrigation measures on the changes of biochemical properties of three soils, and their different effects on the degradation of soil herbicide MCPA. The experimental method is appropriate and the workload is full. However, the idea of this paper is not innovative enough. There are many studies on the influence of soil water management on soil properties and organic matter degradation. At the same time, the paper language is not smooth, some parts of the words do not make sense, need English experts to polish the language. For example, in Abstract: It is not accurate to state that MCPA degradation occurred 45 days after the beginning of the experiment, because the degradation of organic matter occurred all the time, only the degradation rates were different. Therefore, the sentence should be changed to the extent to which the herbicide degrades at a given time.
Author Response
First of all, the authors would like to thank the reviewer for his comments that helped us improve the quality of the manuscript.
After reading your comments, the authors want to highlight that the manuscript does not study the influence of soil water management on soil properties and organic matter degradation.
This study tries to observe how the amount of water and the different physicochemical properties of the soils affect in a different way the biochemical activity of said soils, affecting in a different way the degradation of the MCPA herbicide.
Regarding the language, the authors want to inform you that the manuscript was reviewed by a native English speaker. We do not understand your comment when the other reviewers of the manuscript have not indicated any comments about the language of the manuscript.
