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Peer-Review Record

Growth, Evapotranspiration, and Ion Uptake Characteristics of Alfalfa and Triticale Irrigated with Brackish Groundwater and Desalination Concentrate

Agronomy 2019, 9(12), 789; https://doi.org/10.3390/agronomy9120789
Reviewer 1: Anonymous
Reviewer 2: Anonymous
Agronomy 2019, 9(12), 789; https://doi.org/10.3390/agronomy9120789
Received: 24 September 2019 / Revised: 5 November 2019 / Accepted: 15 November 2019 / Published: 22 November 2019

Round 1

Reviewer 1 Report

The authors have not provided a point-by-point response to my comments, therefore I do not know why they have decided to maintain the gas exchange parameters section in the revised version of the manuscript, among others.

On gas exchange my comments were as follows.

Tables 6 and 7, show extremely low values for gas exchange parameters in both species. The authors argue that a possible reason for these low values would be that the measurements were taken in plants at the end of their growth period (lines 367 – 383), Did plants show any symptoms of chlorosis? It is a matter for concern that these low gas exchange values have low validity, because when working with plants with low photosynthetic capacities, special cuvette designs to prevent diffusion leaks rather than standard clamp-on leaf chambers need to be used. In my opinion, sufficient reliable data to include the gas exchange parameters are not provided and this section should be removed from the manuscript.

Author Response

Response to Reviewer 1 Comments

Point 1: The authors have not provided a point-by-point response to my comments, therefore I do not know why they have decided to maintain the gas exchange parameters section in the revised version of the manuscript, among others.

Response 1: We sincerely apologize for not including a detailed response to your previous comments. Time to revise was only ten days and I submitted the manuscript before addressing the issue.

Point 2: Tables 6 and 7, show extremely low values for gas exchange parameters in both species. The authors argue that a possible reason for these low values would be that the measurements were taken in plants at the end of their growth period (lines 367 – 383), Did plants show any symptoms of chlorosis? It is a matter for concern that these low gas exchange values have low validity, because when working with plants with low photosynthetic capacities, special cuvette designs to prevent diffusion leaks rather than standard clamp-on leaf chambers need to be used. In my opinion, sufficient reliable data to include the gas exchange parameters are not provided and this section should be removed from the manuscript.??? On gas exchange my comments were as follows.

Response 2: Yes, we did determine leaf chlorosis using the visual observation and found that 10-70% plants showed symptoms of chlorosis. However, increasing irrigation water salinity and salt accumulation in the leaf stimulated plant growth and decreased chlorosis. We did not use special cuvette designs but we believe, time of measurement and the salt accumulation in leaf led to the reduced gas exchange in both the species. The low values support the halophytic characteristics of the species. However, as you suggested, we have removed the data from the Tables 6 and 7 and only discussed results with respect to chlorosis and ion accumulation. We sincerely thank you for your comments.

 

Author Response File: Author Response.docx

Reviewer 2 Report

Current MS needs some minor improvements :

Correct the citation of literature in text. See its starting from 54, then 55, then 17. Correct it. Line 106, replace U.S. with “USA” LINE 85-92, ending with “growth and gas exchange.”. move these line to the end of introduction accordingly. Mention each parameter under different subheading of material & method section. Currently everything is in one paragraph which is confusing When citing figures inside text, follow the same pattern throughout the manuscript. i.e. like Figure 1A, Figure 1B. cite specific figure parts according to specific parameter. Avoid citing whole figure for a particular parameter. Table 5. There is no standard deviation/error. Only mean values are there. So authors need to provide SD values also. Avoid comparing your data with earlier works e.g. Adhikari et al. [2] also reported an increase etc. Focus on only discussing the possible mechanisms.

Author Response

Response to Reviewer 2 Comments

Point 1: Correct the citation of literature in text. See its starting from 54, then 55, then 17. Correct it. Line 106, replace U.S. with “USA” LINE 85-92, ending with “growth and gas exchange.”. move these line to the end of introduction accordingly. Mention each parameter under different subheading of material & method section. Currently everything is in one paragraph which is confusing When citing figures inside text, follow the same pattern throughout the manuscript. i.e. like Figure 1A, Figure 1B. cite specific figure parts according to specific parameter. Avoid citing whole figure for a particular parameter. Table 5. There is no standard deviation/error. Only mean values are there. So authors need to provide SD values also. Avoid comparing your data with earlier works e.g. Adhikari et al. [2] also reported an increase etc. Focus on only discussing the possible mechanisms.

Response 1:

We have made the changes to citations as per the journal requirements Line 106 has been replaced with USA instead of U.S (Please see line 47, 97) Line 85-92 ending with “growth and gas exchange” has been moved to appropriate place towards the end of introduction to Line 102- 109 Under Material and Methods section, we separated the paragraphs to make reading clear. We followed uniformity and same pattern while citing figures inside the text throughout the manuscript. We labelled appropriate figures as A1, A2, B1 and B2 as per your suggestions. Table 5. In the mass balance table, total salt values were obtained using composite samples (determined by Harris lab), that is why only means are reported in the table. We have removed some of the earlier work references and focused on our research results and possible mechanisms. We made necessary English language corrections and spell check.

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The manuscript has been revised.  Unfortunately, in my opinion, the reported photosynthesis data still do not provide any useful information to the reader as only one measurement was conducted during late developmental stages producing very low values that mask potential differences among treatment. Moreover, no additional data are provided with the exception of photosynthetic pigment measurements according to visual observations, which is also quite confusing, what criteria was applied? What does 70% chlorosis mean? Does it mean that a 70% of the alfalfa exhibit yellow foliage?

My suggestion to the authors as in the previous version of this manuscript is that, unless they can provide relevant additional photosynthesis data, this section should be completely removed from the manuscript.

Author Response

Response to Reviewer 1 Comments

Point 1: The manuscript has been revised.  Unfortunately, in my opinion, the reported photosynthesis data still do not provide any useful information to the reader as only one measurement was conducted during late developmental stages producing very low values that mask potential differences among treatment. Moreover, no additional data are provided with the exception of photosynthetic pigment measurements according to visual observations, which is also quite confusing, what criteria was applied? What does 70% chlorosis mean? Does it mean that a 70% of the alfalfa exhibit yellow foliage?

My suggestion to the authors as in the previous version of this manuscript is that, unless they can provide relevant additional photosynthesis data, this section should be completely removed from the manuscript.

Response 1: We removed gas exchange and photosynthesis section completely in the manuscript as suggested by the reviewer.

We read the manuscript again and made some changes. For your information, three of the co-authors who reviewed this manuscript are the native English speakers.   

 

Author Response File: Author Response.docx

 

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

 

Round 1

Reviewer 1 Report

Reviewer’s Comments

MS Title: Ion uptake and accumulation responses to evapotranspiration, gas exchange, and plant growth in alfalfa and triticale, by V. Kankarla et al..

 

Overall Comments:

Objectives of this study were to determine the effect of saline irrigation water such as BGW and RO (Na+ and Ca2+ dominant) concentrates on soil and plant ionic concentration, and how that will affect the growth and gas exchange. This ms is well written and provides a wide array of references on the subject. This ms re-confirmed that alfalfa is moderately salt tolerant and triticale is moderately halophyte through greenhouse experiments. Authors found the suitable irrigation sources from combination of saline water for each crop growths and growth parameters. However, authors need to provide the practical analysis on how to recycle the brackish water and RO concentrate for crop production, such as cost and management practices under the field condition. Otherwise this ms seems to diverge from the main objective.  

(Table 1): Use the SAR-Conductivity plot by Richards (1969) for the classification of the experimental irrigation water sources in view of the initial sodium hazard and salinity hazard (US Salinity Lab Staff, Ag Handbook No. 60). All saline irrigation waters initially have a similar salinity hazards but different level of sodium hazards. Reviewer did not see this consideration in the result and discussion sessions. (Control=C2S1; BGW=C4S1; RO=C4S2; and BGW+NaCl = C4S3). In other word, authors used the irrigation water having the initial different levels of salinity and sodicity but compared the data directly among the four treatments. This can mislead the interpretation of the data. Need to calculate the mass balance on the amount of Na and Ca addition to each pot and analyze the data accordingly.

Authors showed results and discussion separately. In the results sessions, they presented only the results but did not show ‘why’. However, in the discussion sessions, contents were not exactly match with the results showing no reason for the results ‘why’. Is it better to combine ‘results’ and ‘discussion’ and try to provide the reasons for the results?

 

Specific Comments:

Title: Considering objective and contents of the ms, Title of this paper may be changed into ‘Impact of saline water irrigation sources on ion uptake, evapotranspiration, gas exchange, and growth of alfalfa and triticale’, since ion uptake and accumulation are redundant, and plant growth is specified as alfalfa and triticale. Key seems to incorporate the effect of saline irrigation water in the title.

 

Line 25 and 26: Na+ accumulation above 0.66 meqL-1 in shoots: how does unit of Na concentration in shoot (solid sample) express as meq/L? Convert meq/L as SI unit of mass basis.

L.32: L. 55-59; L. 398-402: Triticale proved to be a promising species for the reuse of RO concentrate for agriculture in marginal lands: how much of RO concentrate is available for agricultural irrigation use? Distance for transportation? Irrigation facilities or infrastructure to irrigate soil with RO water? Practically or economically feasible? Authors need to include these aspects in the discussion or conclusion.

L.103 and others: For unit of areas, use the SI unit rather than acres

L.116-117; L. 131; L. 16-17 and others: If a soil has 90% sand, 6.28% silt and 3.72% clay, then the soil’s textural class should be defined as ‘Sand’ rather than ‘Loamy Sand’ based on the USDA classification.

L.140-142: Alfalfa needed to be irrigated every 5–6 days and triticale every 9–10 days. A total of 10 irrigations in alfalfa and 13 in triticale were carried out during the entire 90-day crop growth period: As mentioned before, authors may need to calculate the mass balance of input of Na, Ca, and other saline parameters. And compare these parameters with changes of ion in the plants and those in the soil. Since the work is conducted in the greenhouse under the controlled condition, reviewer assumes it is possible to compare the changes (especially Na+ and Ca++) in the irrigation sources-soil-plant continuum.

L.145: ET needs to be spelled out at the first shown case

L.179: he --> The (?)

Table 2, 3, 4, 5 and 6: Use small cases of a, b, c and d for the significance of the data

L. 256 and Table 3: Soil ion concentration? Shoot ion concentration (L. 320)? : Confusing!. Are these data for ion concentration in soil or in plant shoot? In this case, how the unit of data can be meq/L? Convert them into soil mass basis. Title of Table 3 needs to be clarified.

Comments for author File: Comments.pdf

Author Response

Reviewer 1 Comments

MS Title: Ion uptake and accumulation responses to evapotranspiration, gas exchange, and plant growth in alfalfa and triticale, by V. Kankarla et al.,

Overall Comments:

Point 1: Objectives of this study were to determine the effect of saline irrigation water such as BGW and RO (Na+ and Ca2+ dominant) concentrates on soil and plant ionic concentration, and how that will affect the growth and gas exchange. This ms is well written and provides a wide array of references on the subject. This ms re-confirmed that alfalfa is moderately salt tolerant and triticale is moderately halophyte through greenhouse experiments. Authors found the suitable irrigation sources from combination of saline water for each crop growths and growth parameters. However, authors need to provide the practical analysis on how to recycle the brackish water and RO concentrate for crop production, such as cost and management practices under the field condition. Otherwise this ms seems to diverge from the main objective.  

Response 1: We are utilizing the available BGW and the RO concentrate a by-product during desalination of BGW. In coastal desalination plants, RO is disposed of in the ocean, however, in inland desalination plants, it is either injected into deep wells or discarded in evaporation ponds. Both processes are expensive and precious water, although saline, is lost. In dry and desert regions, like New Mexico, where this research is taken up, we are utilizing this water as an irrigation source for growing crops. This research provides a low cost alternate to manage the RO.

Please refer L – 59-60 in the manuscript which explains...

"If properly done, this might be an effective way to recycle RO concentrate without the associated high costs of disposal and concerns about environmental pollution". 

Point 2: (Table 1): Use the SAR-Conductivity plot by Richards (1969) for the classification of the experimental irrigation water sources in view of the initial sodium hazard and salinity hazard (US Salinity Lab Staff, Ag Handbook No. 60). All saline irrigation waters initially have a similar salinity hazards but different level of sodium hazards. Reviewer did not see this consideration in the result and discussion sessions. (Control=C2S1; BGW=C4S1; RO=C4S2; and BGW+NaCl = C4S3). In other word, authors used the irrigation water having the initial different levels of salinity and sodicity but compared the data directly among the four treatments. This can mislead the interpretation of the data. Need to calculate the mass balance on the amount of Na and Ca addition to each pot and analyze the data accordingly.

Response 2: We cannot use USDA salinity handbook 60 because for two of the waters (RO, BGW+ NaCl), the conductivity (8 dS/m) exceeded the scale of the handbook diagram (maximum conductivity of 5 dS/m, i.e., 5000 micromhos/cm, Fig.25, page 80 of the handbook). Therefore, C-S- classifications for these two waters do not exist within the limits of the diagram and cannot be added to table 1.

Certainly, the waters had different levels of salinity and sodicity. For example, the first three treatments in table 1 (control, BGW and RO) had gradually increasing levels of sodicity and salinity. The RO water was Ca-dominant and the BGW+ NaCl (fourth water in the table) was Na dominant for the purpose of determining the effect of increasing Na proportion on the plants.  After careful interpretation (see results section 3.5; Fig. 5), the added Na (BGW+ NaCl) did not cause any growth suppression relative to the RO treatment.

We calculated the mass balance (See table 5) for Na and Ca and found mass balance errors were much higher for calcium because these soils have lot of calcium. Please find new mass balance table 5 attached in the ms. We also found an increase of Na and Ca ions with the increasing irrigation water salinity. The mass errors for the ions accumulated in the roots and the precipitates could not be analyzed at this point in the current study.

Point 3: Authors showed results and discussion separately. In the results sessions, they presented only the results but did not show ‘why’. However, in the discussion sessions, contents were not exactly match with the results showing no reason for the results ‘why’. Is it better to combine ‘results’ and ‘discussion’ and try to provide the reasons for the results?

Response 3: We do recognize the need mentioned by the reviewer to separate out the results and discussion but because of large content, complexity to connect one chapter to the other and to maintain a proper a flow for the reader, we prefer to keep results and discussion separate for now.

Specific Comments:

Point 4: Title: Considering objective and contents of the ms, Title of this paper may be changed into ‘Impact of saline water irrigation sources on ion uptake, evapotranspiration, gas exchange, and growth of alfalfa and triticale’, since ion uptake and accumulation are redundant, and plant growth is specified as alfalfa and triticale. Key seems to incorporate the effect of saline irrigation water in the title.

Response 4: Title of the manuscript is changed as suggested.

Point 5: Line 25 and 26: Na+ accumulation above 0.66 meqL-1 in shoots: how does unit of Na concentration in shoot (solid sample) express as meq/L? Convert meq/L as SI unit of mass basis

Response 5: We apologize for the error made in units of shoot ion concentration. Line 25 and 26 has been changed to the correct units to % for shoot Na concentrations. (See L 26- 27 in the edited manuscript)

Point 6: L.32: L. 55-59; L. 398-402: Triticale proved to be a promising species for the reuse of RO concentrate for agriculture in marginal lands: how much of RO concentrate is available for agricultural irrigation use? Distance for transportation? Irrigation facilities or infrastructure to irrigate soil with RO water? Practically or economically feasible? Authors need to include these aspects in the discussion or conclusion.

Response 6: We have added this explanation in the conclusion section (L. 514-520)

For a desalination plant the recovery percentage varies over a wide range. It depends on what is the water source. An "under the sink" home RO system may have up to 25% recovery while new innovative RO processes can have recovery in excess of 90%. A municipal brackish water RO plant can have 75% recovery and seawater RO will generally have 50% - 60% recovery. It depends upon the type of reverse osmosis membranes used for the process. Whether it is a thin film composite (TFC) membrane, made of thin polyamide layer (<200 nm) deposited on top of a polyether sulfone or polysulfide porous layer (about 50 microns) on top of a non-woven fabric support sheet." Also it depends upon the size of the system and the recovery rate of your system and the desired TDS of your concentrate.

Hence the amount of RO concentrate that could be made available will depend upon the size and the recovery rate of the system and the desired TDS of concentrate. In New Mexico, there are 2 municipal RO plants, one in Rio Rancho that is sized at around 1.4 million gallons per day (mgd) and one here in Alamogordo sized at 1 mgd.  In United States, in 2018, there were 534 desalination plants that were 1 mgd plants and larger. Three hundred of these plants treated brackish water.  In general desalination, plants are not located adjacent to agricultural areas and RO concentrate needs to be transported to agricultural fields depending upon the distance.

Point 7: L.103 and others: For unit of areas, use the SI unit rather than acres

Response 7: All units changed to SI units (See L. 105 in the edited manuscript)

Point 8: L. 116-117; L. 131; L. 16-17 and others: If a soil has 90% sand, 6.28% silt and 3.72% clay, then the soil’s textural class should be defined as ‘Sand’ rather than ‘Loamy Sand’ based on the USDA classification.

Response 8: Based on the suggestion, we repeated soil textural analysis using hydrometer method and corrected on the % of sand, silt and clay. According to the soil textural classification, our soil is ‘sand’ with 93 % sand, 3 % silt and 4 % clay (See L. 118-119 in the edited manuscript).  

Point 9: L. 140-142: Alfalfa needed to be irrigated every 5–6 days and triticale every 9–10 days. A total of 10 irrigations in alfalfa and 13 in triticale were carried out during the entire 90-day crop growth period: As mentioned before, authors may need to calculate the mass balance of input of Na, Ca, and other saline parameters. And compare these parameters with changes of ion in the plants and those in the soil. Since the work is conducted in the greenhouse under the controlled condition, reviewer assumes it is possible to compare the changes (especially Na+ and Ca++) in the irrigation sources-soil-plant continuum.

Response 9: Thank you for raising the subject of irrigation frequency and amount, because we reported an error in the original manuscript for irrigation frequency and corrected in text to read every 9-10 days for alfalfa and every 5-6 days for triticale. A total of 10 irrigations for alfalfa and 13 irrigations for triticale are correct in original. Triticale needed more total irrigations and frequent irrigations compared to alfalfa because it averaged about 40% more total ET and about 33 % higher AGB (dry) across all treatments. We added a general statement to this regard in the 5th paragraph of the revised material and methods at first mention of irrigation frequency and number (See L. 143-147 in the edited manuscript)

As far as the mass balances of Na and Ca, please see the response to the same comment addressed above in the overall comments section, second comment.

Point 10: L. 145: ET needs to be spelled out at the first shown case

Response 10: Yes, changed to Evapotranspiration (ET). (See L. 150 in the edited manuscript)

Point 11: L.179: he --> The (?)

Response 11: Yes, changed to ‘The’. (See L. 192 in the edited manuscript)

Point 12: Table 2, 3, 4, 5 and 6: Use small cases of a, b, c and d for the significance of the data

Response 12: Yes, it has been changed to small letters.

New table 5. (mass balance) has been added, with a total of 7 tables now.

Point 13: L. 256 and Table 3: Soil ion concentration? Shoot ion concentration (L. 320)?: Confusing!. Are these data for ion concentration in soil or in plant shoot? In this case, how the unit of data can be meq/L? Convert them into soil mass basis.

Response 13: We are sorry about the confusion in L.256. In table 3. we clarified the title as “Effect of irrigation water salinity on soil ion concentrations……” rather than “Effect of irrigation water salinity on ion uptake in the soil…”, which misguided the reader. On the unit’s part, we prefer to use the most commonly used matrix for explanation of soil mineral concentration on solution basis which is m eqL-1 rather than soil mass basis. In L.320 we corrected the reference table to 2 and not 3. (See L.311 in the edited manuscript)

Point 14: Title of Table 3 needs to be clarified.

Response 14: Title of table 3 is clarified

 

Submission Date                                                         30 July 2019

Date of this review                                                      05 Sep 2019 10:22:03

 

Reviewer 2 Report

 

The potential of brackish groundwater and reverse osmosis concentrate water for irrigating alfalfa and triticale was studied. Plant height, fresh and dry shoot biomass, evapotranspiration, Na, Ca, Mg and Cl shoot concentrations and gas exchange parameters were recorded to evaluate these crops responses to excess of Ca or Na supply. This is a timely interesting study as climate change threatens freshwater resources due to increased drought among others.

My comments are as follows,

The Medicago sativa variety used in this study needs to be stated in the manuscript as salt tolerance highly varies amongst varieties.

In Material and Methods, the environmental conditions during gas exchange measurements need to be provided (leaf chamber PAR, RH, Tª and CO2). Lines 162-163, it is stated, “The data were recorded on flag leaves…” which leaf was used in alfalfa?

Also in Material and Methods, lines 166-167, it is stated, “All water, soil and plant samples were analyzed by Harris Lab…”; The parameters analyzed in water, soil and plant tissue as well as the method used to conduct the analysis need to be stated in the manuscript.

Why K, a cation with a key role in the plant response to salinity, was only analyzed in the water?

Tables 5 and 6, show extremely low values for gas exchange parameters in both species. The authors argue that a possible reason for these low values would be that the measurements were taken in plants at the end of their growth period (lines 367 – 383), Did plants show any symptoms of chlorosis? It is a matter for concern that these low gas exchange values have low validity, because when working with plants with low photosynthetic capacities, special cuvette designs to prevent diffusion leaks rather than standard clamp-on leaf chambers need to be used. In my opinion, sufficient reliable data to include the gas exchange parameters are not provided and this section should be removed from the manuscript.

Other minor comments,

Please revise figures 2, 3, 4, 5, X-axis legend states “Saline irrigation treatment (dSm-1)” however; conductivity values are only shown for the control treatment (<0.7). Similarly, in tables 2, 3, 4, 5, in the first column “Salinity (dSm-1)”, the conductivity units should be removed.

 

 

Author Response

Reviewer 2 Comments

MS Title: Ion uptake and accumulation responses to evapotranspiration, gas exchange, and plant growth in alfalfa and triticale, by V. Kankarla et al.,

Overall Comments:

The potential of brackish groundwater and reverse osmosis concentrate water for irrigating alfalfa and triticale was studied. Plant height, fresh and dry shoot biomass, evapotranspiration, Na, Ca, Mg and Cl shoot concentrations and gas exchange parameters were recorded to evaluate these crops responses to excess of Ca or Na supply. This is a timely interesting study as climate change threatens freshwater resources due to increased drought among others. My comments are as follows,

Point 1: The Medicago sativa variety used in this study needs to be stated in the manuscript as salt tolerance highly varies amongst varieties.

Response 1: Yes, it has been changed (See L. 86-87)

Point 2: In Material and Methods, the environmental conditions during gas exchange measurements need to be provided (leaf chamber PAR, RH, Tª and CO2). Lines 162-163, it is stated, “The data were recorded on flag leaves…” which leaf was used in alfalfa?

Response 2: The environmental conditions inside the leaf chamber were as follows: PAR was set between 800 - 1000 µ mol m⁻² s⁻¹, RH 15- 20%, Tair was 25- 28 0C and CO2 ranged between 399-400 uml. In alfalfa the oldest trifoliate leaflets were used to measure gas exchange. (Added in L. 168-169)

Point 3: Also in Material and Methods, lines 166-167, it is stated, “All water, soil and plant samples were analyzed by Harris Lab…”; The parameters analyzed in water, soil and plant tissue as well as the method used to conduct the analysis need to be stated in the manuscript. Why K, a cation with a key role in the plant response to salinity, was only analyzed in the water?

Response 3: In soil and plant tissues, we analyzed Na, Ca, Mg and Cl. Initially, we analyzed the irrigation water being used for the experiment for Na, Ca, Mg, K and Cl using Inductively coupled plasma atomic emission spectroscopy (ICP-OES) to understand the chemical properties. However, we did not measure K in in soil or the plant tissue because we did not apply K to the soil and the cost of analysis was high and therefore it was not measured.

At Harris lab the leachate samples were analyzed using Inductively coupled plasma atomic emission spectroscopy (ICP-OES) for Na, Ca, Mg and Flow Injection Analysis (FIA) was used for Cl analysis. (Added in L. 172-180)

Point 4: Tables 5 and 6, show extremely low values for gas exchange parameters in both species. The authors argue that a possible reason for these low values would be that the measurements were taken in plants at the end of their growth period (lines 367 – 383), Did plants show any symptoms of chlorosis? It is a matter for concern that these low gas exchange values have low validity, because when working with plants with low photosynthetic capacities, special cuvette designs to prevent diffusion leaks rather than standard clamp-on leaf chambers need to be used. In my opinion, sufficient reliable data to include the gas exchange parameters are not provided and this section should be removed from the manuscript.

Response 4: Yes, the plants showed symptoms of chlorosis towards the end of plant growth when the gas exchange parameters were recorded. Please find some pictures illustrating the chlorosis below:

 

These pictures were taken on the day of harvest (90th day) and show up to 30% chlorosis which varied with the treatments. Our Licor measurements were taken 5 and 10 days before harvest (80-85th day) much better than the images shown above. A similar study conducted by our earlier lab researcher, on triticale grown in sand soil, using LiCOR reported high photosynthetic rates (PN) 13.38, 12.03 and 11.29 at 0.6, 4.1,8.0 dS/m respectively and no chlorosis in sand soil, when measurements were taken at 60 and 90 days. However, our results with10-30% chlorosis resulted in low photosynthetic rates (PN).

Other minor comments,

Point 5: Please revise figures 2, 3, 4, 5, X-axis legend states “Saline irrigation treatment (dSm-1)” however; conductivity values are only shown for the control treatment (<0.7).

Response 5. All the graphs have been revised as suggested.

Point 6: Similarly, in tables 2, 3, 4, 5, in the first column “Salinity (dSm-1)”, the conductivity units should be removed.

Response 6. Yes, all conductivity units were removed as suggested.

 

Submission Date                                                                                 30 July 2019

Date of this review                                                                              11 Sep 2019 11:54:15

Author Response File: Author Response.docx

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