Effectiveness of Cover Crop Termination Methods on No-Till Cantaloupe

Round 1

Reviewer 1 Report

Manuscript “Effectiveness of cover crop termination methods on no-till cantaloupe” by Kornecki and Kichler reports termination rates and soil moisture content of difference termination methods on three crop crops and the impact of cantaloupe yields in no-till cantaloupe. Manuscript is somewhat loose and long and discussion is relatively simple, but important information is reported. I have added some comments in the attached file. I have two main concerns: one is related to the description of the field experiment and other one is how the results were reported. I suggest that it should be described in more detail to better understand the experimental field history and to make it easier for the authors to explain the yields and the readers to follow the text. I also suggest simplify reporting over three growing seasons termination rates for each cover crop by reporting the DAT 21 data only. Some edits and suggestions can be found in attached PDF file. 

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

Thank you for providing an excellent suggestions to improve our manuscript. 

Below are our responses to your comments/suggestions (in bolt text)

Manuscript “Effectiveness of cover crop termination methods on no-till cantaloupe” by Kornecki and Kichler reports termination rates and soil moisture content of difference termination methods on three crop crops and the impact of cantaloupe yields in no-till cantaloupe.

Manuscript is somewhat loose and long and discussion is relatively simple, but important information is reported. I have added some comments in the attached file. I have two main concerns: one is related to the description of the field experiment and other one is how the results were reported.

I suggest that it should be described in more detail to better understand the experimental field history and to make it easier for the authors to explain the yields and the readers to follow the text.

The following information was added on page 3, lines 126 –129:

Prior to this no-till cantaloupe experiment, a tomato test performed on plasticulture was conducted in the experimental area. Before planting cover crops for this test, the field was disked in the fall of 2009. There was not any tillage done between each growing season for this experiment.

I also suggest simplify reporting over three growing seasons termination rates for each cover crop by reporting the DAT 21 data only.

After careful consideration, we decided to keep termination results after 7 and 14 days after rolling.  We need to underscore that this experiment evaluated the effectiveness of agricultural equipment (roller/crimper prototypes and flail mower) at terminating cover crops. We collected large amounts of data for our prototype evaluation. Three weeks of the evaluation was performed in Alabama soil and climatic conditions. The period of three weeks is needed between cover crop termination and planting the main crop into desiccated and flatten cover crop residue.  This is recommended by agricultural extension services to minimize competition for water and nutrients between cover crop and the cash crop. However, if the spring is wet and cold, this three-week time needs to be reduced possibly to 2 weeks and even less (10 days) to preserve recommended planting dates for this area.

 Some edits and suggestions can be found in attached PDF file. 

Corrected to “Agricultural”

In materials and Methods:

Was this study an organic trial? No fertilization information (especially fertilizer N) was mentioned. If it was not, please include fertilization practices in M&M. If it was an organic one, please describe how the field was managed before this experiment. This information is critical for understanding the huge differences in cantaloupe yield between 2012 and 2010. If the 2010 was the first year of organic NT, then it was very likely the soil nutrient status, particularly the N nutrition, was much better in 2010 than in 2012.  

This was not an organic study and the fertilizing schedule was included beginning in line 231 through line 235 of the manuscript:  Prior to transplanting cantaloupe seedling, 43 kg ha^-1 of nitrogen was applied to all plots using calcium nitrate.  Post-transplanting, 11.2 kg ha^-1 of nitrogen was applied weekly alternating between calcium nitrate and general purpose 20-20-20 water-soluble fertilizer. Weekly fertilization for the entire test was performed using drip irrigation.

Already defined in L51

Latin description: Secale cereale L. was removed on page 4, line 147 form the superscript.

Changed to 55 deg (superscript) Celsius

needs clarifying - Non-rolled cover crops or No cover crops? If non rolled cover crops, how the cover crops were terminated, naturally dead?

On page 5 lines: 176-181 following information was added:

Mechanical termination effectiveness using rollers/crimpers and flail-mower was compared with the untreated (non-rolled) cover crop. However, the control treatment with respect to cantaloupe yield was the flail mowing method. Transplanting cantaloupe into flail mowed residue is a more practical operation for a no till-system. In contrast, in Alabama, planting the cantaloupe seedlings into an untreated, non-rolled cover crop is impractical.

clearly points out that the termination rate increased with time. 

We clearly stated this on page 10, lines 295-296: termination rates for each cover crop by week using flail mowing and different rollers (termination treatments) increased with time (weeks of evaluation)

Table 7-9?

Table 7, 8, 9 are not referred in manuscript. Considering so many tables in this manuscript, I recommend considering to merge the data in Tables 7,8,9 into one table or figure, showing the 21 DAT which is the key numbers for this study -plant transplanting happens after this. The trend of the termination rate increase with termination time has already clearly demonstrated in Table 6.

We referenced tables 7, 8 and 9 in the manuscript.  Below is an explanation why we think that separate tables are needed:

The separation of the 3 cover crops and their termination data is a key part of the discussion and needed to differential between the 3 termination methods.  Introductions to each table in their associated discussion sections has been added.  Combining these 3 tables into one table showing just the 3-week termination data would dilute the information and maybe even increase confusion about what the advantages/disadvantages of the termination methods actually are and how they relate to different types of cover crops.   Yes, the general trend of increasing termination rate with time exists, but the discussion includes instances where the termination is above 90% at earlier DATs indicating cash crop planting could be performed prior to 3 weeks after termination.  This shows an advantage to some termination methods with the ability to plant earlier. 

Green bar refers to rainfall, what purple far refers to? 

Added information regarding the purple bars to the caption below the graph with unusually high rainfall events (above 190 mm).

Would be better if some discussion will be given for why the 2011 data differ from the 2010 and 2012 data.

On page 16, lines 503 – 509, following information was provided:

Weather patterns for this year contributed to this which include the heaviest rainfall for all three growing seasons for April of 2011 followed by the least rainfall for May of 2011 out of the 3 years.  Biomass production for 2011 was also the least (3605 kg ha^-1) out of all three growing seasons. Soil moisture left over from April slowly dissipated throughout the month of May thus allowing termination treatments to show differences with the roll/crimped treatments having increased VMC for all three weeks compared to the flail mowed and control treatments.

Also, on page 16, lines 519-523 we added:

The low biomass along with the heavy plant damage caused by the flail mower result-ed in the soil surface loosely and unevenly covered resulted in higher soil evaporation and moisture lost. In contrast, compared to the rolled/crimped cover crops that were pressed against the soil surface with stems left interconnected, thus not allowing more soil moisture to escape.

could huge differences for fruit number and weight as well as the final yields be related to soil nutrients, such as N which was not measured and discussed?

We added additional information on page 2, lines 73 - 77 and 83 - 87 regarding cover crops and nutrients, especially Nitrogen.

showed in table or figure?

We modified Table 15 on page 18, line 545, by providing treatment effects for combined years (2010 and 2012) with respect to fruit weight as rolling, mowing treatments were significant.

substantially less

We added “substantially” on page 19, line 574

if this study was an organic trial, then plant nutrients may play an big role for lower yield in 2012.

The study was not an organic trial. It was no-till system for cantaloupe with selected cover crops: mono (cereal rye) and mixture (cereal rye, crimson clover and hairy vetch) with different residue management (termination) practices.

Reviewer 2 Report

The manuscript presents the results of 2009-2012, but there is no fresh data? 10 years have passed

Author Response

Dear Reviewer,

Thank you for your comments to improve our manuscript.

The manuscript presents the results of 2009-2012, but there is no fresh data? 10 years have passed.

The Northern Alabama Research Station had served scientists both from Auburn University and the ARS, the National Soil Dynamics Laboratory. Thus, the site was not available for additional field experiment beyond 2012 growing season. In fact, a decision was made by Auburn University administration for to close this research location in 2015.

Reviewer 3 Report

Dear editor,

The article "Effectiveness of cover crop termination methods on no-till cantaloupe" is interesting. The article was very well structured and with a great experimental design. However, there are some points that need further clarification, with emphasis on the Material and Methods item. The main points that I believe should be explained are:

- In the Introduction, I suggest exploring possible soil compaction problems due to the use of machinery (tractors/equipment used) during the management of cover crops.

- Why was the statistical analysis done with a 10% probability, since 5% is usually used?

-What is the history of the cultivation area, that is, what was there before the implementation of the experiment with cantaloupe?

- Was fertilization and liming done before planting the cantaloupe?

-Must present a physical-chemical characterization of the soil, at least for the 0-10 cm layer. This is very important for us to understand the development of cover crops, and finally, the response of cantaloupe yield.

-Put in the Material and methods that have taken measurements of temperature and precipitation. Make it clear that irrigation was not used in the cantaloupe crop.

- Cover plants have different chemical characteristics, as they are from different plant species (i,g, grasses vs. legumes). They have different types of root systems, which influence the exploration of different volumes of soil, as well as different carbon inputs to the soil. These characteristics should be explored in the discussion when talking about the efficiency of the evaluated treatments, biomass production, etc.

-Perhaps it would be important to carry out a multivariate analysis, for example, a principal component analysis (PCA), to verify the grouping pattern of the different treatments (covers x terminations methods x productivity).

Author Response

Dear Reviewer,

Thank you for providing valuable comments to further improve our manuscript:

our response is provided below (in bold text) 

The article "Effectiveness of cover crop termination methods on no-till cantaloupe" is interesting. The article was very well structured and with a great experimental design. However, there are some points that need further clarification, with emphasis on the Material and Methods item. The main points that I believe should be explained are:

- In the Introduction, I suggest exploring possible soil compaction problems due to the use of machinery (tractors/equipment used) during the management of cover crops.

Authors added discussion on page 2 lines 51 - 70 by citing previous research (two citations) regarding soil compaction issues from rolling cover crops and transplanting main crops:

Questions are often brought up about soil compaction when discussing reoccur-ring rolling/crimper over the same area. In response to these concerns, a field experiment was conducted by Kornecki et al (2013) [7], evaluating soil compaction during 2007-2009 at the Cullman, Alabama location after rolling cereal rye and mixture (rye, crimson clover, and hairy vetch) once, twice or three times. Researchers [7] concluded that multiple rolling operations did not cause soil compaction on the non-wheel traffic area. During drought conditions in 2007, soil strength (soil compaction indicator) for the rolled residue was 42% lower compared to higher soil strength for cereal rye and mixture controls (7.2 MPa), implying that rolled down cover crops help reduced soil strength by conserving moisture by covering the soil surface with a mulch layer. Furthermore, rolling two or three times over the same non-wheel traffic area did not in-crease soil compaction. Higher gravimetric soil moisture in 2008 and 2009 lowered soil strength below 2 MPa, a critical value for root penetration resistance (Taylor and Gardner, 1963) [8].

Another field experiment conducted by Kornecki (2020) [9] with different roll-ers/crimpers evaluated soil strength in both the plot area (area only where roll-er/crimper bars contacted) and in the tractor’s wheel track, before and after rolling cover crops. This study indicated that rolling two or three times over the same plot area did not cause soil compaction either in the plot area or wheel track. Data also showed that for the top 15 cm of soil, the soil strength value did not surpass 2 MPa, a level of restriction for root penetration [8] and was solely related to changes in gravimetric soil moisture content (GMC).

1. Kornecki, T.S., F.J. Arriaga, A.J. Price, and K.S. Balkcom. 2013. Effects of recurrent rolling/crimping operations on cover crop termination, soil moisture, and soil strength for conservation organic systems. Applied Engineering in Agriculture. Vol. 29(6):841-850.

 

2. Kornecki, T.S. 2020. Influence of Recurrent Rolling/Crimping on Cover Crop Termination, Soil Strength and Yield in No-Till Cotton. MDPI AgriEngineering 2020, 2(4), 631-648; https://doi.org/10.3390/agriengineering2040042

 

- Why was the statistical analysis done with a 10% probability, since 5% is usually used?

On page 8, lines 239 - 243, it was stated:

“Treatment means were separated using the Fisher’s protected Least Significant Differences (LSD) test at the 10 % probability level with respective probabilities (p-values), meaning there is a 10% chance weather and nature could have contributed to the differences observed, which is common with agricultural field experiments.

Below are some examples regarding alpha = 0.10:

The significance level (often referred to as alpha or “α” in scientific studies) selected is solely at the discretion of the researcher. The scientific community in general prefers a significance level of 90% (α = 0.1) or 95% (α = 0.05), meaning that a researcher can state with 90% or 95% probability that the difference between treatments did not occur by sheer chance. Cited from:  https://ohioline.osu.edu/factsheet/anr-40

The significance level for a given hypothesis test is a value for which a p-value less than or equal to is considered statistically significant. Typical values for are 0.1, 0.05, and 0.01.  Cited from website: http://www.stat.yale.edu/Courses/1997-98/101/sigtest.htm

It is a convention to set the level at 0.05, while 0.01 and 0.10 levels are also widely used.

https://mpra.ub.uni-muenchen.de/66373/1/MPRA_paper_66373.pdf

The least significant difference is always noted at a certain confidence level, usually 90 or 95 percent, which tells you the probability that a Type I error could occur. For example, a 90 percent confidence level means there is still a 10 percent chance the difference was actually due to natural variation. Sometimes you will see the confidence level identified by its corresponding alpha value: A 95 percent confidence level has an alpha of 5 percent (LSD 0.05) and a 90 percent confidence level has an alpha of 10 percent (LSD 0.1). Anything less than 90 percent certainty is usually not considered scientifically valid.

https://www.sare.org/publications/how-to-conduct-research-on-your-farm-or-ranch/basic-statistical-analysis-for-on-farm-research/

-What is the history of the cultivation area, that is, what was there before the implementation of the experiment with cantaloupe?

The following information was added on page 3, lines 126 - 129:

Prior to this no-till cantaloupe experiment, a tomato test on plasticulture was conducted in the experimental area. Before planting cover crops for this test, the field was disked in the fall of 2009. There was not any tillage done between each growing season for this experiment.

- Was fertilization and liming done before planting the cantaloupe?

The soil for these experimental areas at this station are sampled for general analysis frequently and recommended amounts of amendments are applied to keep the soil within range of the crops being produced. The general analysis sample collected prior to this experiment has acceptable nutrient levels and pH so no amendments were applied prior to beginning the experiment.

These results are presenting in the manuscript in methods on page 3, lines 136 – 139 as follows:

Soil’s extractable nutrients from the test results include: Phosphorus (P = 166 kg ha^-1); Potassium (K = 290 kg ha^-1); Magnesium (Mg = 229 kg ha^-1) and Calcium (Ca = 2042 kg ha^-1) which were all at the optimum level (high or very high) for cantaloupe production.

-Must present a physical-chemical characterization of the soil, at least for the 0-10 cm layer. This is very important for us to understand the development of cover crops, and finally, the response of cantaloupe yield.

A paragraph regarding soil’s physical and chemical properties added on page 3 lines: 130 -136.

The Hartsells soil consists of moderately deep, well drained, moderately permeable soil, formed in loamy residual weathered from acidic sandstone containing thin band of shale or siltstone with 11% clay, 26% silt and 63% of sand. At the top layer (depth from 0 to 127 mm), the soil is dark grayish brown with weak fine granular structure; very powdery with many fine roots (10%) and sharp fragments of sandstone. In preparation for this test, a general analysis soil sample was collected that indicated a pH of 6.4 in which liming was not recommended prior to initiated this test.

-Put in the Material and methods that have taken measurements of temperature and precipitation. Make it clear that irrigation was not used in the cantaloupe crop.

Figure 6. Monthly rainfall amounts (in mm) along with maximum and minimum temperatures in degrees Celsius during three growing seasons: October 2009 to August 2012 was moved to Materials and methods (page 7, line 211, with the caption: lines 212-214.

- Cover plants have different chemical characteristics, as they are from different plant species (i,g, grasses vs. legumes). They have different types of root systems, which influence the exploration of different volumes of soil, as well as different carbon inputs to the soil. These characteristics should be explored in the discussion when talking about the efficiency of the evaluated treatments, biomass production, etc.

We added followed information on page 2, lines 73-77:

Cereal rye has the potential for high biomass amounts both above and below the soil. Rye is known for taking in unused nitrogen from previous crops (scavenging) as well as brining up potassium near the soil surface by the root system.  However, the benefit from the nitrogen uptake is often not noticed in succeeding cash crop due to slow mineralization after termination or maturity [11].

Also we added information for the legumes; page 2, lines 83-87:

Crimson clover can produce biomass in the range of 3923 to 6165 kg ha^-1 of dry matter whereas hairy vetch produces slightly less at a range of 2578 to 5604 kg ha^-1 dry matter with vines that can reach up to 3.7m in length. Nitrogen fixation from crimson clover can provide from 78 to 168 kg ha^-1 of nitrogen and even more for hairy vetch with a range of 101 to 224 kg ha^-1 [11].

-Perhaps it would be important to carry out a multivariate analysis, for example, a principal component analysis (PCA), to verify the grouping pattern of the different treatments (covers x terminations methods x productivity).

We did not carry out multivariate analysis.  We strongly believe that our statistical analysis we presented in the manuscript are correct. These analysis were consulted with our professional staff statistician at the Southeast Area of the Agricultural Research Service.  

Reviewer 4 Report

The most of comments are inserted in text.

Additionaly, my personal opinion is there is no need for all of these variance analysis tables. The other point which should be reconsidered is the control treatment for cantaloupe yield.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

Thank you for providing valuable comments and suggestions to further improve our manuscript. 

Our responses are presented below (bold text).

The most of comments are inserted in text.

Additionaly, my personal opinion is there is no need for all of these variance analysis tables.

We decided to keep tables which show analysis of variance. We would like to inform that all our statistical analysis we presented in the manuscript were first consulted with our professional staff statistician assigned to work with scientists at the USDA Southeast Area of the Agricultural Research Service. 

The other point which should be reconsidered is the control treatment for cantaloupe yield.

On page 5 lines: 176 -181, following paragraph was added to explain controls for cover crop termination and for cantaloupe yield.

Mechanical termination effectiveness using rollers/crimpers and flail-mower was compared with the untreated (non-rolled) cover crop. However, the control treatment with respect to cantaloupe yield was the flail mowing method. Transplanting cantaloupe into flail mowed residue is a more practical operation for a no till-system. In contrast, in Alabama, planting the cantaloupe seedlings into an untreated, non-rolled cover crop is impractical.

peer-review-15701162.v1.pdf

Submission Date

23 September 2021

Date of this review

16 Nov 2021 10:10:12

 

PDF file downloaded. agriculture-1413386-review-Reviewer #4

Please use SI units like kg or tons

Used “Metric tons”

Make it shorter: 34.18° N; 86.85° W; 244 m above sea

Made this shorter as suggested (page 3, line 123).

Make space between text nad table title. Apply through text.

Corrected throughout the text.

Make space between table note and text.

Corrected

1. 'Athena', please specify seed company

Provided company name that supplied seedlings for mechanical transplanting.

I think there is no need for this table because the same equipment is used for all cover crops. It is mentioned in text.

This table 2 was removed

Is this 55° C? Please check.

It was corrected (superscript) should be 55 degrees Celsius

Changed to “cover crops”

What is this? Please check!

Table 6:2012 was typo. This was corrected to Table 6, we removed :2012 (page 10, line 304)

3.2.3. was corrected

Figure 7; should be mentioned in text, probably in section 3.3.

We changed the Figure number from 7 to 8 (page 17, line 540 and mentioned this in text on page 18, line 560.

Please cite them.

Citations were provided [ 7, 15, 30, 31], page 15, line 489.  

fruit weight

Changed from “Weight per fruit” to “Fruit weight”

Figure 8; should be mentioned in text

Mentioned in the text page 18, line 546

3.3.3. Cantaloupe yield, fruit number and fruit weight

This sub-title was removed.

What is used as a control? You have just compared different cover crops. What about bare soil, or soil covered with plastic mulch as a control?

Was explained in the manuscript: On page 5 lines: 176 -181:

Mechanical termination effectiveness using rollers/crimpers and flail-mower was compared with the untreated (non-rolled) cover crop. However, the control treatment with respect to cantaloupe yield was the flail mowing method. Transplanting cantaloupe into flail mowed residue is a more practical operation for a no till-system. In contrast, in Alabama, planting the cantaloupe seedlings into an untreated, non-rolled cover crop is impractical.

Fruit weight

Was corrected

Please use SI unit.

The unit was corrected to SI (metric tons)

There were no significant differerences determined.

Corrected in the conclusion

Round 2

Reviewer 4 Report

The manuscript has been sufficiently improved and I suggest it for publication in present form.