Microbiological Properties in Cropping Systems and Their Relationship with Water Erosion in the Brazilian Cerrado

Round 1

Reviewer 1 Report

The research work is very extensive and valuable, but I found some points to be enhanced in the manuscript:

- 1) Figure 1: must be improved.

It will be useful to include a map with the topography and hydrology of the area. Perhaps the map on the top right corner could be eliminated.

In addition, some reference to land use in the area could be included in the text, in order to bring a general idea.

 

- 2) No comments regarding Rainfall data? This should be included: in general for the whole treatment period, and in particular for the sampling period. For the sampling period it will be useful to know the characteristic of each rainfall event, since it is directly related to the rainfall erosivity.

Also temperature could be included, at least for the sampling period.

Rainfall and temperature are only mentioned in the description of the area in Materials and methods section, citing a reference from 2013.

 

- 3) More details about microbial biomass could be included. Which were the main species found?

 

- 4) p. 93-94: it is mentioned that “The experimental site was then separated into stripes with terraces between each other, creating a single large experimental block as each stripe being each treatment.”; but it is not specified if the experiment was separated from outside experiment’s upstream plots.

Could surface runoff generated outside the experiment be affecting the plots? For example by introducing water and/or sediment generated upstream the experiment? This should be clearly expressed.

 

- 5) p. 99-101: it is mentioned that “with two additional treatments with a high level of fertilizers input, being MS-HI and MBSB-HI, while the other treatments were maintained with a medium input of fertilizers.”; but I could not found the assumed concentration of fertilizer for “medium input” and for “high level”. I believe this information must be included.

 

- 6) Revise English details through the whole manuscript, but especially in the Discussion section.

Author Response

Reviewer #1 comment No. 1: “The research work is very extensive and valuable, but I found some points to be enhanced in the manuscript:

- 1) Figure 1: must be improved.

It will be useful to include a map with the topography and hydrology of the area. Perhaps the map on the top right corner could be eliminated.

In addition, some reference to land use in the area could be included in the text, in order to bring a general idea.”

R.- Figure 1 has been improved. In the new manuscript version, this became Figure 2. The map on the top right corner was eliminated, as suggested. Unfortunately, there is no way to insert topography and hydrology information since we used image from Google Earth figure. However, we insert the slope direction for better understanding.

The previous land use of the area was already described in the manuscript (Lines 92-93 “Prior to the experiment setting up, the area had been used for maize and soybean production under conventional soil tillage for more than two decades”).

 

Reviewer #1 comment No. 2: “No comments regarding Rainfall data? This should be included: in general for the whole treatment period, and in particular for the sampling period. For the sampling period it will be useful to know the characteristic of each rainfall event, since it is directly related to the rainfall erosivity.

Also temperature could be included, at least for the sampling period.

Rainfall and temperature are only mentioned in the description of the area in Materials and methods section, citing a reference from 2013.”

R.: Thank you very much for the observation and suggestion. To accommodate the reviewer's request, a new figure was prepared (Figure 1) and inserted into the manuscript. It contains information on sampling times, rainfall and average temperature. However, it was not possible to calculate the rainfall erosivity because there was no data on the intensity of the rains.

 

Reviewer #1 comment No. 3: “More details about microbial biomass could be included. Which were the main species found?

R.- The analysis carried out does not allow to distinguish the species present in the soil.

 

Reviewer #1 comment No. 4: “p. 93-94: it is mentioned that “The experimental site was then separated into stripes with terraces between each other, creating a single large experimental block as each stripe being each treatment.”; but it is not specified if the experiment was separated from outside experiment’s upstream plots.

Could surface runoff generated outside the experiment be affecting the plots? For example by introducing water and/or sediment generated upstream the experiment? This should be clearly expressed.”

R.- The experimental strips were separated by terraces, so there was no water flow between treatments.

In the quantification of erosion, information about the erosion plot was inserted in the manuscript (lines 128-131 “In December 2018, three unitary erosion plots of 1 m² (0.5 m width x 2 m length) were implemented for each treatment, arranged with their length on the direction of the slope. Erosion plots were delimited by galvanized zinc sheet metal inserted 0.20 m into the soil and kept 0.20 m above the soil surface”).

 

Reviewer #1 comment No. 5: “p. 99-101: it is mentioned that “with two additional treatments with a high level of fertilizers input, being MS-HI and MBSB-HI, while the other treatments were maintained with a medium input of fertilizers.”; but I could not found the assumed concentration of fertilizer for “medium input” and for “high level”. I believe this information must be included.”

R.- Fertilization information was entered, as suggested. (Lines 104-112 “The treatments differed by soil management practices such as different crop rotation systems and different levels of fertilizer input. Monocultures of soybean (SS) and maize (MM) were compared to rotation systems of maize-soybean (MS) and maize-Brachiaria-soybean-Brachiaria (MBSB) and two additional treatments with a high level of fertilizer input, designated MS-HI and MBSB-HI, while the other treatments were maintained with a medium fertilizer input. The amounts of fertilizeres applied were 148, 250, 250, 250, 415 and 415 kg ha-1 of NPK 08-28-16 + 0.3% boron and 2.1% sulfur for the treatments SS, MM, MS, MBSB , MBSB-HI and MS-HI, respectively. For 2018/2019 crop season, maize was grown in MS and MBSB treatments, and soybeans in MSSB-HI and MS-HI.”):

 

Reviewer #1 comment No. 6: “Revise English details through the whole manuscript, but

especially in the Discussion section.”

R.- The manuscript was proofread by a native speaker:

Reviewer 2 Report

This is an interesting paper, thank you.

Author Response

Reviewer #2 comment No. 1: “This is an interesting paper, thank you.”

R.- Thank you for taking your time to read the manuscript.

Reviewer 3 Report

The Manuscript (MS) is dealing with the relationship between various soil-management methods and soil-physical-chemical indicators. The authors wanted to see the differences in monoculture of soybean and maize and their intercropping methodology and learn the erodability in soil-water storing capacity and soil loss in general. The concept is very good and it is in relation to Journal's aim. The data obtained are valuable and informative also for farmers, potential stakeholders. Methods used are generally accepted and in situ might give information to readers. The authors are using statistical methods, as well to show their results in a well-supported way. It is known already from the literature survey, that Brazilian Cerrado soil is good quality soils, in which the growing of plants (i.e. sugarcane) can grow even without additional inorganic fertilizers (Johanna Döbereiner, personal comments). So, it is very important to show the relevance of crop rotation and/or intercropping with native cover crops, and also to assess the soil-biological status in this process. The final sentence of abstract, as “not only physical and chemical but also biological properties are deeply affected by erosion” could be improved as an opposite way of thinking: „biological improvement of soils by the suggested ecologically supported management methods can reduce water-affected soil erosion. Authors should mention also it considering their presented results. Partly it is addressed in the literature survey and results were supported.

The MS can provide practical information to potential readers and is well-written. Suggested for publication in its present form.

Author Response

Reviewer #3 comment No. 1: “The Manuscript (MS) is dealing with the relationship between various soil-management methods and soil-physical-chemical indicators. The authors wanted to see the differences in monoculture of soybean and maize and their intercropping methodology and learn the erodability in soil-water storing capacity and soil loss in general. The concept is very good and it is in relation to Journal's aim. The data obtained are valuable and informative also for farmers, potential stakeholders. Methods used are generally accepted and in situ might give information to readers. The authors are using statistical methods, as well to show their results in a well-supported way. It is known already from the literature survey, that Brazilian Cerrado soil is good quality soils, in which the growing of plants (i.e. sugarcane) can grow even without additional inorganic fertilizers (Johanna Döbereiner, personal comments). So, it is very important to show the relevance of crop rotation and/or intercropping with native cover crops, and also to assess the soil-biological status in this process. The final sentence of abstract, as “not only physical and chemical but also biological properties are deeply affected by erosion” could be improved as an opposite way of thinking: „biological improvement of soils by the suggested ecologically supported management methods can reduce water-affected soil erosion. Authors should mention also it considering their presented results. Partly it is addressed in the literature survey and results were supported.

The MS can provide practical information to potential readers and is well-written. Suggested for publication in its present form.”

R.- Thank you for reviewing the manuscript and for noting the new way of analyzing the data. Thus, the sentence at the end of the abstract was rewritten. (Lines 31-33 “Thus, not only physical and chemical, but also biological properties are deeply affected by erosion aiding in early monitoring of water erosion. Soil quality improvement in ecologically supported management contribute to mitigate erosion”).