Sustainable and Traditional Irrigation and Fertigation Practices for Potato and Zucchini in Dry Mediterranean Regions

Response to Reviewer 1 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: [Based on my review, the authors have made the required revisions and submitted the revised version. The content is now clearer and more aligned with the standards, particularly in terms of the presentation of data. Therefore, I believe the manuscript now meets the journal's requirements and can be accepted.

Response 1: [Thank you for your kind review]

4. Response to Comments on the Quality of English Language

Point 1: The quality of the English language in the revised manuscript has significantly improved. The text is now clearer, and the ideas are more effectively conveyed. There are only a few minor grammatical issues and sentence structures that could still be polished for better readability. Overall, the manuscript is well-written and the language is suitable for publication, with only minor improvements needed in certain areas.

Response 1:    (Thank you for pointing this out. We reviewed the structure and amended the English style).

Response to Reviewer 2 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: [Comments and Suggestions for Authors]:

The manuscript shows a comparative study between traditional irrigation and fertilization practices with those scientifically recommended, based on the SEALACOM Project, which represents an excellent scientific contribution to sustainability by implementing demonstration units for scientific dissemination to farmers, as an example of changing paradigms.

The methodology is very well written, with clear and direct language, presenting enough details to reproduce the research.

All tables and figures are properly cited in the text, and all citations are listed in the references section.

The authors named the Results and Discussion section but presented them separately. On page 8 it begins only with the presentation of the results and only on page 15 does the discussion of the results, compared to the literature begin.

The manuscript was well carried out and generally well presented, but some comments and suggestions are necessary, which are inserted directly in the manuscript attached to the Journal system.

Response 1: Thank you for pointing this out. We fully agree with this comment. Therefore, we have separated Results and Discussion. Changes can be found in the revised manuscript in P. 15 L 502.

Comments 2: The acronym for grams in the International System of units is just "g"

Rectify throughout the manuscript.

Response 2: Agree. We have changed gr to g. Please see P.1, L. 26.

Comments 3: I suggest not using words that already appear in the title as Keywords.

Response 3: Agree. We have changed fertigation to fertilization.

Comments 4: Considering the importance of the sealacom project in implementing experiments, I suggest adding a paragraph about it in the introduction.

Response 4: Thank you for this important suggestion. The paragraph was modified (L. 140-148) to: Meeting the objectives of the SDGs and addressing challenges to boost national capacities in the food-water-energy nexus, a project named “SEALACOM” was launched in 2023. It aimed to sustainably manage sea and land resources by the community, support development, sustain the environment, and strengthen farmer resilience. Accordingly, the purpose of this paper is to compare locally prevailing unsustainable fertilizaion and irrigation practices with science-based techniques and climate-smart practices proposed by the Project. It assesses the impact in terms of water and nutrient saving and efficient use for two open field crops (potato and zucchini) cultivated under two different pedoclimatic conditions, following the traditional and advanced fertigation methods.

Comments 5: Add "Lebanon"

Response 5: Added (P. 4, L. 15).

Comments 6: Use MDPI reference style

Response 6: Done (P.4, L. 175)

Comments 7: It is necessary to inform which classification system was used to identify these types of soil: Soil Survey Staff ? Italian system? Lebanese system?

Response 7: The paragraph was modified (P.5, L. 197-199) to: According to the World Reference Base for Soil Classification [30], the area of the two DSs is represented by the dominance of Cambisols, Regosols and Luvisols with inclusion of Vertisols, Calcisols, Leptosols, Arenosols and Andosols (Figure 3). 

Comments 8: Explain how the ETc value was defined

Response 8: The paragraph was changed to (P. 5/6, L. 212-259): The daily crop evapotranspiration (ETc) was defined by multiplying ETc by the crop coefficient (Kc). Crop coefficient (Kc) was proposed by Jensen [31] and used together with the FAO guidelines to estimate crop water requirements [32] to relate the evapotranspiration of a specific crop (ETc) to the calculated potential evapotranspiration (ET0) according to the equation:

             ETc= ET0*Kc                                   (1)

Where ETc is the Daily Crop Evapotranspiration [mm/day]

ET0 is the Daily Reference Evapotranspiration [mm/day]

Kc is crop coefficient

Comments 9: Or ET0?

Response 9: This sentence and equation were deleted and incorporated within the previous paragraph.

Comments 10: Table 5?

Response 10:  Yes, corrected to table 5 (P. 10, L. 330)

Comments 11: This information needs to be reviewed, as the Tuber gr range in figure 9 goes up to 3500 gr

Response 11: Thank you. Actually the harvested area for calibration, from each replicate, was 2.8 m². The harvest was weighted was calibrated. Then, each size was aeighted separately. The maximum scale on Y2 axis is the weight of each category of he corresponding tuber size. (Please see the table below).

Also, to avoid duplicate, Figure 9 was removed.

Comments 12: I suggest placing all indexes, 1, 2 and 3 of this table, in the footer of the table and not the page.

Response 12: Thank you. Done.

Comments 13: Delete it

Response 13: Deleted (P.16, L. 543).

4. Response to Comments on the Quality of English Language

Point 1:

Response 1:    The English was improved.

Response to Reviewer 3 Comments

1. Summary

Thank you very much for taking the time to review and suggesting improvement to our manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: The "Sustainable Irrigation and Fertigation Practices for Potato and Zucchini in Dry Mediterranean Regions" by Darwish, T., Shaban, A., Faour, G., Jomaa, I., Moubarak, P., Khadra, R. was very interesting to get familiar with. As the problem of water supply and increasing the harvest/input ratio is very important all over the World and exceptionally in arid zones.

Response 1: Thank you.

Comments 2: The name of the piece does not correspond to the abstract, that tells about advantages of SEALACOM plots compared with traditional farming. The title has also small reflection of the total content of the presented manuscript. The description of the experimental sites and methods is too scarce. 

Response 2: Thank you. The title was modified to: Sustainable and Traditional Irrigation and Fertigation Practices for Potato and Zucchini in Dry Mediterranean Regions

Comments 3: The overall impression is that many authors have contributed to the piece that has weak logic links between parts written (maybe) by different authors. 

Response 3: Thank you. The first draft of the manuscript was written by the first author and reviewed by the co-authors.

Comments 4: Conclusions are weak. Text is about SEALACOM methodology to assess crop water demand, but it is only WORDS. Methodology is still covert and is not described at all. As follows from the presented material: the different rates of fertilizers (NPK+Mg not shown how to calculate) plus mini-sprinklers (instead of standard dripping system) lead to the almost 50% water saving for potatoes production... That's all.

Response 4: Thank you. The conclusion is built on the experimental results and reflects the advantage of followed methods of fertigation, notably, the continuous feeding mechanism, to save water and fertilizers that has economic and environmental impact, notably in drylands (P. 18, L. 618-621). Please see the amendment: The efficient use of water and nutrients will reduce energy consumption for water pumping and application. Water and fertilizer saving by continuous feeding has economic and environmental impact, notably in drylands.

On the other hand, the methodology of the calculation of nutrients was explained in P. 6, L. 212-260: Fertigation schedules usually divide the portion of the total recommended rate of nutrient to be injected into varying amount or percentages for each application over the growing season. Small amounts (low concentration) are usually injected in the early plant growth stage, larger amount at mid-season, then it is diminished toward the end of the season. The overall picture is similar to the dynamic of the crop fraction (Kc). Therefore, nutrient concentrations (i.e., N, P, K, Mg) were adjusted according to the crop’s age, starting from 50 mg/l and increasing to a maximum of 100 mg/l, with proportional increases in major and minor nutrients to meet the crop’s growing demands.

The basic factors in fertigation procedures to be taken into account are:

a.     Injection rate (injection pump capacity)

b.     Amount of material to be injected

c.     Time available for injection

The injection rate (a=b/c) must be calibrated using a graduated cylinder 1000 ml as a container and a watch to control how much of the nutritive solution is injected in one minute. To calculate the mass of dry fertilizer (m) to be dissolved for the preparation of stock solution we used the following equation.

        M = b* df* v*100                                                           (2)      

                                 c

Where M is the mass of soluble fertilizer (Kg).

b is the concentration of the final nutritive solution (mg l^-1 or Kg m^-3)

df is the dilution factor (unitless)

v is the volume of the barrel to prepare the stock solution (m³)

c is the concentration of the given fertilizer

Therefore, to prepare 100 liters or 0.1 m³ of stock solution, with a desired concentration (b) of the final solution equivalent to 100 mg l^-1 (100 g m^-3 or 0.1 Kg m^-3) of nitrogen (N), at a dilution factor (df) =100, i.e., one liter of stock solution is injected against 100 L of irrigation water we proceeded as follow: The used fertilizer is Ammonium Sulfate (c=21.5% NH₄-N). To calculate the needed amount of this fertilizer to be dissolved in 100 L barrel, the calculation was done as follows:                             

M= 0.1 Kg m^-3 * 100 * 0.1m³ * 100% = 4.651kg

                        21.5%                         

Comments 5: This manuscript have to be generally overrated, rewritten and definitely re-named before any reader can understand the ideas of authors and enjoy the clearly presented results of the big work done.

Response 5: Thank you. The manuscript was renamed and amended.

Comments 6: Here are some particular and striking facts (in the manuscript) that made me write down the remarks. I underline that it is only my opinion, but i would like authors to be aware of it.

Response 6: Thank you. It was useful.

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Comments 7: In lines 18 and 19 values of irrigated water are provided with difference in two orders of magnitude, i and readers (probably) would  have question WHY?

Response 7:  Thank you. The paragraph was amended to look like: Against 225 L of water to produce 1 Kg of fresh zucchini by the SEALACOM Project, the farmer applied 359 L, indicating a significant, 60%, water saving in the SEALACOM practice.

Comments 8: SEALACOM abbreviation is often used in the abstract but never decrypted.

Response 8: Thank you. At the end of the introduction, a paragraph was inserted shading light on SEALAOM project (P. 3, L. 140-148): Meeting the objectives of the SDGs and addressing challenges to boost national capacities in the food-water-energy nexus, a project named “SEALACOM” was launched in 2023. It aimed to sustainably manage sea and land resources by the community, support development, sustain the environment, and strengthen farmer resilience.

Comments 9: The sentences in lines 21-26 depict lowering the application rates for different nutrients, which is interesting but have nothing in common with discovering the essence of study! This lines could be deleted from abstract with no evident damage to it!!! Moreover, in lines 25-26 the phrase construction is too complex to understand and enjoy reading. 

Response 9: Thank you. The essence of the study (L. 21-26) is the comparison between traditional farmer practices and advanced practices of water and nutrient management. Therefore, nutrients are part of the two components precluded in the term fertigation. The sentence in lines 25-26 was modified to (P.1, L. 25-27): To cultivate 1 kg of fresh potato tubers, SEALACOM utilized 4.06 g of nitrogen and 1.34 g of phosphorus, compared to the traditional practice which required 13.2 g of nitrogen and 2.25 g of phosphorus.

Comments 10: Authors write about Lebanon in first sentence of Introduction section, as the manuscript title has no evidence of this narrow regional particularity, whole wide Mediterranean Regions are "included" in the title. Why to give such a "wide" name when discussing only one "narrow" region?

Response 10: The dry Mediterranean conditions exist all over the world. Dry Mediterranean conditions, characterized by hot, dry summers and mild, wet winters, suitable for the cultivation of many crops, can be found in several regions around the world, including southern Europe, North Africa, West Asia, California, USA, Central Chile and Southwestern Australia. Therefore, findings of the work can be useful for other countries.

Comments 11: Line 34 "...reduce precipitation by 2.7% by 2025" is absurd - we're already in 2025, and the manuscript submission date is also 2025 (January) - yet it shows no prospect and no real forecast!

Response 11: It seems the Reviewer was not informed about the history of the manuscript. As part of a project, the experimental work was done in fall 2023 and the first article on greenhouse cucumber was submitted and published in summer 2024 (https://doi.org/10.3390/su162210050). This paper on field crops is a revised version. It was prepared and submitted in November 2024.

Comments 12: Economical costs are given in absolute values (line 37), as the reader should be aware (!) of the Lebanon's economics and its average profits/losses, which is not quite easy for the reader.

Response 12: I suppose nothing is wrong with bringing the damage to national economy caused by climate change in US Dollars. The reference is pesented in the reference list. To clarify the dimension, the paragraph was modified to (L. 34-38): With the continuation of current trends in water scarcity, the direct costs to Lebanese economy caused by higher temperatures, fluctuated precipitation, and drought event is estimated to reach USD 138,900 million in 2080, equivalent to 1.71% of current national gross domestic product [3].

Comments 13: Lines 57-62 are about regulation and implementation of climate friendly farming and sustainable use of water and nutrient resources (as I've thought), but it is very difficult to understand the authors' idea in the presented form.

Response 13: Thank you. The paragraph was modified to (L. 59-62): Integrating climate-proof agriculture into a comprehensive management approach involves monitoring soil and climatic conditions and considering crop water and nutrient demands in relation to crop growth and development. This can support pro-active decision-making to anticipate economic and environmental losses.

Comments 14: The "draw the map toward ... community innovation" in line 65 looks weird in piece about "Sustainable Irrigation...".

Response 14: Thank you. This statement must be considered as part of the following sentences, to be better understood, within the context of the national policy to modernize the agricultural sector, which was approved by the Lebanese Government. It states (L. 66-74): A comprehensive multiscale analysis that couples plot scale tests with district-wide assessments can be useful to identify the technical and socio-economic driving forces behind low water productivity and yield gaps and to support the adoption of modern irrigation technology. The 3-year national development priorities and strategy to revive the Lebanese national economy through targeted investments in various sectors [13], along with the Ministry of Agriculture five-year strategic Plan [14], proposed investing in capacity building and upgrading the technical basis and productivity of irrigated agriculture. They also call for innovation campaigns in fertilization and irrigation practices, which can contribute significantly to national economic growth and recovery.

By “advanced development and community innovation” we stress the need to upgrade the technical skills of farmers and introduce field measurement tools to measure and monitor soil, water and crop status for sustainable food production.

Comments 15: Authors declare, that there is still the need to evaluate and assess existing practises of irrigation and fertilization (lines 73-75), but already know the answer to the question that would be posed after analysis: "how to improve these practices?" As for me, there is huge logical gap that should be filled in before the manuscript can be considered for publication!

Response 15: Thank you. Based on the principle concept: we can manage what we measure, there is always a need to analyze and monitor farming practices to reassess and reveal the gaps and improve (introduce) good practices. Therefore, We see no gaps in the approach and results/conclusions made.

Comments 16: Mentioned "IT intervention" to fight for sustainable adaptation strategy (line 78) is also far beyond the theme indicated in title.

Response 16: Thank you for raising this issue. Sustainable fertigaion is based on information technology and measurements received from the climatic sensors to calculate crop evapotranspiration. Water application is also related to the information on crop growth cycle. The precise application of nutrients and water is also related to soil information, equipment to control pressure in the irrigation network and use of modern, proportional injectors, to control the amount and form of applied fertilizers.

Comments 17: No evidence of footage to compare two potato producing regions - Lebanon and Northern China - is provided (lines 117-119). Even different references  are provided for this statement for two territories.

By the words of authors, published studies (line 126) consider water outlay to cover evapotranspiration and the next we (and wide row of farmers) should know about water saving practices (lines 131-133) and apply it. Which is right now not widely used due to "weak extension service" (line 131). Authors should definitely explain how do they come to this conclusion.

Response 17: Thank you. It is believed that drought and water scarcity is a global issue. Authors represent several institutions working for decades in the farming and water sectors in Lebanon and across the Mediterranean. Therefore, they have sufficient knowledge about the gaps and needs for capacity building to sustainably manage water resources. The SEALACOM project was launched to target the sustainability of the water-food-energy nexus. The sentence (L. 132-136) states: “A weak extension service is an additional constraint to the dissemination of good agricultural practices and effective water management in the semi-arid areas. Therefore, it is crucial to create and sustain living labs and demonstration (and experimental) sites in the main agroclimatic zones of the East and South Mediterranean. These sites ensure continuous interaction and participatory learning with local farmers.”.

Living labs and farming schools are among the priorities of the UN and EU programs to transfer and improve the skills for water management and boost the adaption/mitigation of climate change.

Comments 18: Materials and methods section starts with reaching the SEALACOM Project objectives (line 145) that are not listed and/or referenced anywhere above, and the abbreviation itself is still never decifered. And these objectives are (aren't they?) not correspond to the manuscript goals.

Response 18: Thank you. Just before the M&Ms, a paragraph was inserted to introduce the objectives of the SALACOM project: “Meeting the objectives of the SDGs and addressing challenges to boost national capacities in the food-water-energy nexus, a project named “SEALACOM” was launched in 2023. It aimed to sustainably manage sea and land resources by the community, support development, sustain the environment, and strengthen farmer resilience”.

Comments 19: "Instead of using the relatively expensive, high precision dosatron injectors, the project used the feasible venturi system to modify the concentration of the final solution and control the ratio between nutrients" (lines 226-227) What was the system exactly?

Response 19: Thank you. The system was fertigation using proportional injectors called venturi system. They are feasible for the farmers. In our previous research we used Dosatron which are much more expansive. But both devices work with the same injection principle and provide the same services. Venturi can serve larger areas.

Comments 20: In lines 235-242 it is stated the only difference in treatment was continuous/intermittent supply of fertilizers to plants? Is it right?

Response: 20: Thank you. The statement (L. 279-281) is:” SEALACOM used full fertigation with drip lines following the approach of continuous application of fertilizers and water. The farmer also used the drip system but he used the traditionally followed intermittent application of nutrients”. It is not the only difference but it is the main difference between the traditional and advanced fertigation practices in the area. Although, both parties used the same fertilizers, the approach of irrigation scheduling and estimation of water and nutrient amounts were also different.

Comments 21: Table 2 (line 291) duplicates text. What does mean "basic" and "effectively applied" in Tables 3 and 11? Also the question rises, if different fertilizers application schemes are used (included different quantities of substances, mentioned in lines 303-305 and Table 4), is it cost-effective to integrate new ones into practice? The calculations for the applied amounts of N (by SEALACOM methodic) are not presented in text. Graphs though are provided, but serve as no help or insight to understand the authors' idea (see Figures 8 - 10). Figure 8 and Table 6 are doubling the information in Tables 4 and 5 (the same is for Table 11 and Figure 10 vs. Table 12). The units of measurement in Figures 8 - 10 are not clear, gaps are larger than contents.

Response: 21: Thank you. The text comments table 2. The difference between "basic" and "effectively applied" water in Tables 3 and 11 is the following: Basic water application was done for the land preparation and soil moistening before the appearance of young seedlings. Effective application is the water applied with the consideration of crop coefficient (Kc) from seedlings to physiological maturity.

Both parties (SEALACOM project and Farmers) applied the same type of fertilizers. The difference is in the amount. It is cost effective and environmentally friendly to reduce the input and get the better results.

We added a comment (L. 392-394) on applied N: While the farmer applied 58.25 g of nitrogen to produce 1 Kg of fresh zucchini, SEALACOM achieved a nitrogen saving of 9.82 g by applying only 38.48 g.

Table 4 presents the amount of nutrients applied by the unit area. Table 5 really duplicates figure 8, therefore, table 5 was deleted.

Table 11 presents the amount of applied fertilizers and nutrients per unit area while figure 10 presents the amount of nutrients to produce 1 Kg of fresh product.

Table 12 shows the ratio between major nutrients. The units of measurement in Figures 8 - 10 were made clear.

Comments 22: Figure 7 is not convincing as not supported by measurements.

Response: 22: Thank you. Figure 7 shows the difference in greenness between the two treatments reflecting different content of chlorophyll and photosynthetic activity. This observation was linked with the NDVI value of each treatment and showing discrepancy in the value and explaining the higher yield obtained by the SEALACOM methodology. Therefore, we decided to replace the qualitative figure (P. 11) with a quantitative, measured, data of NDVI.

Comments 23: Too much numbers but no sense in it in Table 9. (3) in Table 11 is not interpreted, as long as (2) does not exist.

Response: 23: Thank you. Sorry but this table shows the results, statistical analysis and significant difference in the obtained tubers calibrated into commercial average and elite categories, which is important for the commercial value of the produce. Footnotes are placed under the table. To avoid duplicate, Figure 9 was removed. In able 11 (now 10), footnote 2 and 3 exists interpreted and in the revised version all 3 footnotes were placed under the table.

Comments 24: Units of measurement are different in lines 442-444 from the similar for Zuccini-part. Why?

Response: 24: Thank you. These are two different crops and their need for nutrients is different to produce the same unit of fresh mass.

Comments 25: Sub-section is definitely needed after Table 13.

Response: 25: Thank you. Subsection Discussion was introduced after table 13 (now 12)

Comments 26: Statements in lines 477-479 are already "sociology applied" that is very interesting, but does not correspond to the stated goals of study.

Response: 26: Yes, thank you. But this statement is linked to dissemination and adoption of new technologies and tools by the famers, which is within the scope of the work.

Comments 27: Decrease in groundwater levels is also not directly subjected in this piece (lines 489-491).

Response: 27: Thank you. The sustainable use of groundwater is within the subject of this article because farmers rely on private wells to secure water for irrigation. Thus, over irrigation and over exploitation of water wells are part of the problems addressed by the project to improved farmer’s resilience to drought and water scarcity.

Comments 28: The results (mentioned in line 519) are amazing! But authors show no way to reproduce/repeat it - no method is described and no data shown (only yield is demonstrated).

Response: 28: Thank you. Many data were introduced in the revised version allowing for the replication of the work.

Comments 29: Also i should mention the very low quality of pictures presented in figures.

Response: 29: Thank you. The quality of the figures was improved.

Comments 30: SOC abbreviation in line 40; SDG abbreviation in line 61; IT abbreviation in line 78; ET abbreviation in line 92; GW abbreviation in line 93; WUE (IWUE) abbreviation(s) in line 119; O.M. abbreviation in table 1 etc. are not decrypted anywhere before.

Response: 30: Thank you. The full name of abbreviations was included in the revised paper.

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1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Yes/Can be improved/Must be improved/Not applicable

All raised points were considered and the text improved.

Are all the cited references relevant to the research?

Yes/Can be improved/Must be improved/Not applicable

Is the research design appropriate?

Yes/Can be improved/Must be improved/Not applicable

Are the methods adequately described?

Yes/Can be improved/Must be improved/Not applicable

Are the results clearly presented?

Yes/Can be improved/Must be improved/Not applicable

Are the conclusions supported by the results?

Yes/Can be improved/Must be improved/Not applicable

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1:  L 207 Please, write which nutrients were used for the clarify sentence “Nutrient concentrations were adjusted according…

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, I have modified the paragraph to become: Nutrient concentrations (N, P, K, Mg) were adjusted according to the crop’s age, starting from 50 mg/l and increasing to a maximum of 100 mg/l, with proportional increases in major and minor nutrients to meet the crop’s growing demands. Changes can be found in L 201-203.

Comments 2: The Figure 6 is there no data's of significant difference to calculate

Response 2: Thank you for raising this point. I have revised he paragraph mad changed/modified to: Since the demonstration trial was run directly on the farmer’s land and separate harvest on SEALACOM plot and Farmer’s plot, 0.3 ha each, was being undertaken on a daily basis, weighed and sent to the local whole sale market, we counted he cumulative yield in each treatment. Therefore, there was no replicates in Zucchini trial and the statistical analysis could not be run. Changes can be found in L. 260-264.

Comments 3: L274 “Farmer applied 19.5% more nitrogen and 19.6% more phosphorus and 286.8% less potassium and 142% less magnesium (Table 11).” Yes its understandable that its more but compare what is more

Response 3: Thank you for highlighting this point. Based on your kind notice, I revised the sentence and justified the use of more K and Mg in local, Ca-saturated soils with calcareous pH. The paragraph became: Farmer applied 19.5% more nitrogen and 19.6% more phosphorus than the SEALACOM project applied on its plot. However, farmer applied 286.8% less potassium and 142% less magnesium compared to the project approach. The project focus on sufficient application of K and Mg is justified by the significant contribution of K to plant resilience to climatic conditions (Darwish et al., 2015) and crop yield (Whang et al., 2020). Beside the status of local high soil pH and soil saturation with exchangeable Ca, the researchers from the region highlighted the depletion of Mg from the soils and stressed the important role of Mg and necessity of adding magnesium fertilizers (El-Fouly et al., 2010) to maintain nutrient balance and boost the soil fertility (Table 11). The modifications can be found, respectively, on L. 279-287 and 494-496 and 554-555 and 508-509.

Darwish T., Fadel A., Baydoun S., Jomaa I., Awad M., Hammoud Z., Halablab, O., and Atallah, Th. 2015. Potato performance under different potassium levels and deficit irrigation in dry sub-humid Mediterranean conditions. International Potash Institute, e-ifc N 43, December 2015: 14-20. http://www.ipipotash.org/en/speech/index.php.

Wang, Z., Hassan, MU., Nadeem, F., Wu, L., Zhang, F., and Li, X. 2020. Magnesium Fertilization Improves Crop Yield in Most Production Systems: A Meta-Analysis. Front. Plant Sci. 10:1727. doi: 10.3389/fpls.2019.01727

El-Fouly, M.M. Rezk, A.I., Nofal, O.A., and Abou El-Nour, E.A.A. 2010. Depletion of magnesium in Egyptian soils, its content in crops and estimated needs. African Journal of Agricultural Research, 5 (10): 1060-1067, DOI: 10.5897/AJAR09.087

Comments 4: L405 in the Discussion part it would be good to say about development of practice use high doses of nitrogen for different plants and reaction can vary especially for the plant production and depending from climate conditions etc.

Response 4: Thank you for helping to enrich the discussion; The paragraph became: SEALACOM practice was more efficient in N and P utilization by the potato crop (Figure 10). Since the soils of the area are deficient in organic and mineral nitrogen (Darwish et al., 2006), it is recommended to develop the farming practice of using sufficiently high doses of nitrogen for different crops considering the soil and climate conditions, especially the plant reaction and tolerance to drought, improvement of carbon and nitrogen metabolism, the production goals and water use efficiency (Olšovská e al., 2016; Sun et al., 2020; Su e al., 2020).

Olšovská, K.; Sytar, O.; Kováˇcik, P. 2016. Optimizing Nitrogen Application for Enhanced Barley Resilience: A Comprehensive Study on Drought Stress and Nitrogen Supply for Sustainable Agriculture. Sustainability 2024, 16, https:// doi.org/10.3390/su16052016

Su, W., Ahmad, S., Ahmad, I., Han, Q. 2020. Nitrogen fertilization affects maize grain yield through regulating nitrogen uptake, radiation and water use efficiency, photosynthesis and root distribution. Peer J. 8:e10291 DOI 10.7717/peerj.10291

Sun, J., Li, W., Li, C., Chang, W., Zhang, S., Zeng, Y., Zeng, C. and Peng, M. 2020. Effect of Different Rates of Nitrogen Fertilization on Crop Yield, Soil Properties and Leaf Physiological Attributes in Banana Under Subtropical Regions of China. Front. Plant Sci. 11:613760. doi:10.3389/fpls.2020.613760

You can find the modified text, respectively, in L. 404-410 and 557-559 and 565-469.

Comments 5: In the Discussion There is no direct comparison with similar projects or technologies, which would have strengthened the argument for SEALACOM as an innovative solution. Including case studies or comparisons with other irrigation systems could provide a better perspective on its relative benefits.

Response 5: Thank you for pointing to this gap. The discussion was enriched and compared with other works executed earlier in the country and region. The text is: The results obtained in the SEALACOM approach using mini sprinkler showed similar and comparable trends with earlier studies on potato performance and water use efficiency run in the country using drip system (Darwish et al., 2006; Karam et al., 2013; Karam et al., 2014). Our results showed better performance of the Spunta variety compared to the one tested in the Jordanian desert (Don-nelly et al., 1997). Similarly with the drip irrigated squash in Syria (Darouich et al., 2020), our results continuously presented a higher water productivity, i.e., better biomass production per unit of applied water, explained by the higher irrigation frequency and less water applied per each event.

Karam, F., Massaad, R., Skaf, S., Breidy, J., & Rouphael, Y. (2013). Potato response to potassium application rates and timing under semi-arid conditions. Advances in Horticultural Science, 25(4), 265–268. https://doi.org/10.13128/ahs-12761

Karam, F., Amacha, N., Fahed, S., EL Asmar, T., and Domínguez, A. 2014. Response of potato to full and deficit irrigation under semiarid climate: Agronomic and economic implications. Agricultural Water Management, 142, 144-151, https://doi.org/10.1016/j.agwat.2014.05.007.

You may find the changes, respectively, in L. 451-458 and 519-.521 and 519-512.

Comments 6: The Conclusion can be more shorter and précised. 

Response 6: Very grateful to raise this issue. The conclusion was shortened and made clear. The SEALACOM advanced methodology for assessing crop water demands and applying metered irrigation achieved increased yield and higher water use efficiency. This is crucial in the era of increased drought incidences, which exacerbate water scarcity and pressure on limited water resources. Compared to traditional practices, the improved SEALACOM fertigation method resulted in over a 22 % increase, from 1417 Kg ha^-1 to 1729 Kg ha^-1, in higher-quality zucchini yield, more than 23% water savings and over 43% higher water productivity. Farmers expressed in a video that they will adopt the continuous feeding approach instead of intermittent fertilization, using a modern injector rather than a closed tank. Local farmers were trained on the advanced fertilization and irrigation techniques. In continuous feeding, higher yields and better quality zucchini and potatoes were obtained with doubled nitrogen and phosphorous use efficiency. For potato production, the improved practice using mini-sprinklers and continuous feeding resulted in a 17.8% yield increase from 1900 Kg ha^-1 to 2200 Kg ha^-1, with a 40% increase in large tuber size. The project methodology provided a better nutrient ratio formulation, aligning with soil conditions and crop demands to major nutrients. Water and nutrient saving will reduce energy use for water pumping and application. Demonstrating water accounting and productivity based on totally and effectively applied water can help disseminate good, proactive practices, enhancing food production with a lower environmental footprint, higher sustainability, reduced production costs and better commercial value of the final product.

Changes are presented in L. 482-503.

4. Response to Comments on the Quality of English Language

Point 1:

Response 1:    (The quality of English was slightly improved)

5. Additional clarifications

Thank you.

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Yes/Can be improved/Must be improved/Not applicable

All raised points were considered and the text improved.

Are all the cited references relevant to the research?

Yes/Can be improved/Must be improved/Not applicable

Is the research design appropriate?

Yes/Can be improved/Must be improved/Not applicable

Are the methods adequately described?

Yes/Can be improved/Must be improved/Not applicable

Are the results clearly presented?

Yes/Can be improved/Must be improved/Not applicable

Are the conclusions supported by the results?

Yes/Can be improved/Must be improved/Not applicable

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: The introduction contains extensive background information on climate change and water resource challenges (e.g., lines 36-50). While these help emphasize the importance of the research, their relevance to the specific research topic is relatively weak. It is recommended that the background information be simplified. Retain key data on climate change and groundwater extraction while reducing excessive historical context and general descriptions. Highlight the objectives and significance of the study by clearly stating them at the beginning or in the middle of the introduction.

Response 1: Thank you for pointing this out. I agree with this comment. Therefore, I have modified and simplified the introduction to become:

Climate change scenarios predicted an average rise of the mean annual temperatures in Lebanon of 1.45°C by mid-century, associated with an average decrease in precipitation by 7.5% by 2100 (MoE/UNDP, 2016). With the continuation of current trends in water scarcity, the direct costs to Lebanese economy was estimated to reach USD 1,900 million in 2020, rising to USD 138,900 million in 2080, resulting from higher temperatures, fluctuated precipitation, drought events and a reduction in agricultural productivity threatening food security (MoE/UNDP/GEF, 2015). Water scarcity can cause yield reduction that can be opposed by controlled irrigation to maintain a sustainable crop production (Garg and Dadhich, 2014). However, the extreme hydrologic drought reduced the positive effect of SOC sequestration, decreased wheat yield up to 39% and increased CO₂ and N₂O emission from the soil (Wang et al., 2024). Efforts towards enhancing on-farm irrigation management are crucial to face the growing challenges for a finite resource and maintain food production (Abdelmoneim et al., 2023)

Changes can be found in L 36-49.

Comments 2: The materials and methods section does not clearly specify the irrigation method used for potatoes and zucchinis, nor does it indicate the amount of irrigation applied. It is recommended to include images illustrating the irrigation methods used in the experimental plots.

Response 2: Thank you for pointing to this issue. I modified the paragraphs to completely cover the irrigation techniques: Zucchini (Cucurbita pepo) was cultivated in Serein (DS1) in open filed on a total area of 6000 m² starting also from August 2023. The field was subdivided into two equal parts 3000 m² each. The SEALACOM project managed 3000 m² and the farmer managed the other 3000 m². The soil and irrigation water were similar in both treatments. Land preparation and time and density of sowing of the same Zucchini variety were also identical. SEALACOM used full fertigation with drip lines following the approach of continuous application of fertilizers and water. The farmer also used the drip system but he fallowed he traditionally followed intermittent application of nutrients.

Potato (Solanum Tuberosum ), variety Spunta, was grown in Sultan Yacoub (DS2) on a total area of 2000 m². The farmer managed the control plot of 1000 m² using the closed tank for fertilizer injection and macrosprinklers. SEALACOM project managed the neighboring plot of 1000 m². He also followed intermittent application of nutrients. The project applied continuous feeding with the same type of fertilizers using venturi system, complemented by improved water management and application using mini-sprinklers.

You can find the modified text, respectively, in L. 221-234.

Comments 3: Figure 6 presents the zucchini yields obtained using two methods, but it does not explain how the yields were measured.

Response 3: The title of Figure 6 is: Cumulative yield of harvested commercial Zucchini (Kg ha^-1) by continuous fertigation (SEALACOM) against traditional (Farmer) practices. I hope the term cumulative clarifies the method of the measurement of the yield.

Comments 4: The study frequently mentions the effectively applied water, but does not explain how it is calculated.

Response 4: Thank you for pointing to this weak point. I introduced a paragraph in the introduction clarifying this point: Previous research did not often consider the total amount of water applied staring from land preparation, amelioration of pre-sowing land moisture, and post-sowing water application to maintain minimal conditions for good sprouting. They mainly count water application related to the crop coefficient (Kc) after the seedling establishment, i.e., crop irrigation papers account for the effectively applied water.

You can find the modified text, respectively, in L. 128-132.

Comments 5: Line 170: The rest of the year is dry with mean high and low annual temperature reaching 25.6° and 8.5° C. Ensure consistent unit representation on both sides of "and." Line 174: and low annual temperature reaching 24.56° and 10.85° C. Pay attention to the uniformity of unit usage.

Response 5: Thank you for pointing to the unit uniformity issue. The text was modified: The mean annual climatic data were received from the climatic stations of Tal-Amara (LARI, 2024). DS1 is located within the semi-arid climatic zone with 566 mm of annual precipitation falling in one season between November and March (Figure 2). The rest of the year is dry with mean high and low annual temperature reaching 25.6° C and 8.5° C, respectively.

DS2 belongs to the dry-subhumid climatic zone with annual rainfall of 700 mm and mean high and low annual temperature reaching 24.6° C and 10.8° C, respectively.

You may find the changes, respectively, in L. 170-174 and 177-178.

Comments 6: The creation of figures and tables lacks standardization. For example, the x and y axes in figures should be clearly labeled and uniformly formatted.

Response 6: Very grateful to raise this issue. The figures axes were standardized in track changes, except figure 8 and 10 with P2O5 and K2O, which were impossible to modify in excel and turn into P₂O₅ and K₂O.

Comments 7: There is inconsistency in unit usage throughout the paper, such as "Kg" vs. "kg" and "kg m^-3" vs. "Kg/m³".

Response 7: The units were homogenized in all tables and throughout the text in track changes.

Comments 8: Lines 314-315: The representation of nutrient types in Table 11, Table 13, Table 19, and Figures 8 and 10 is incorrect

Response 8: Thank you for helping to improve the representation of the paper. Nutrients types were modified in all tables and the right number of table sequence was done. However, it was impossible in excel to modify P2O5 and K2O into P₂O₅ and K₂O.

Comments 9:  Lines 265-266: "corresponding to 169.78 m3 and 129,44 m³" requires uniform formatting

Response 9: Thank you. The units were corrected to 169.78 m³ and 129,44 m³ . You may find the correction in L. 280 in the revised version.

Comments 10:  Lines 268-269: "which is equivalent to 1.75 kg m^-3 - 2.51 kg m^-3 and 2.78 kg m^-3 - 4.45 kg m^-3 in traditional farmer’s practice and SEALACOM practice, respectively." Ensure consistency with units in tables.

Response 10: Thank you. Units were corrected to 1.75 Kg m^-3 - 2.51 Kg m^-3 and 2.78 Kg m^-3 - 4.45 Kg m^-3 and consistent with the units in Table 3. You may find the correction in L. 282 and 284 in the revised version.

Comments 11: Data to the right of effectively applied water productivity DM² tubers in Table 18 of Line 379, removing units carried after the data.

Response 11: The units represent footnotes and they were placed in other locations.

Comments 12: Line 360: "we tested the dry matter content and compared the two practices based on four replicates of subsamples dried in the oven at 72 ℃ for three days." Ensure correct unit formatting.

Response 1: Corrected. L. 380 in the revised version.

4. Response to Comments on the Quality of English Language

Point 1: The writing in the results and discussion sections is somewhat confusing and difficult to understand. It is recommended that the results and discussion be separated into separate sections to improve clarity and readability.

Response 1: Since we deal with two different crops, cultivated in parallel in two separated places, it might be not recommended to split results and discussion for every crop that can distract the average reader.

5. Additional clarifications

Thank you.

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Questions for General Evaluation

Does the introduction provide sufficient background and include all relevant references?

Are all the cited references relevant to the research?

Is the research design appropriate?

Are the methods adequately described?

Are the results clearly presented?

Are the conclusions supported by the results?

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: The authors write that they divided the 0.6 ha plantation into two equal parts. The first part is management according to the SEALACOM project and the second part is traditional management by the farmer. Unfortunately, there is no information on the number of replicates or their area, although the analysis of means and confidence intervals and standard deviation, as well as minimum and maximum values, is carried out later in the manuscript.

Response 1: Thank you for your important remark. Actually, the work was based on applied r4serach at the farmer’s plots with direct participation of farmers in 50% of field work. Therefore, the land was divided into two equal parts: he SEALACOM project demonstration trial and the farmer’s land. While famers followed traditional practices of fertilization and irrigation, we introduced the advanced techniques and tools of fertigation. Given the fact that the Zucchini was harvested on a daily basis, and the farmer’s periodically undertook the process of harvest and reported the yield, it was difficult to make repetition with full respect of precision in harvesting and counting yield from a unit area with replicates. However, for the second crop, potato, it was feasible for the research team to organize a random sampling at physiological maturity, from a specific area (1m²), replicated four times, and carry the statistical analysis. I pointed to the statistical analysis concerning the potato crop in the text (Changes can be found in L 249-252). The text became: Statistical analysis for potato crop was done using the descriptive statistics on Excel 2016. The means of yields, tuber calibration and dry matter content, randomly harvested at physiological maturity from 1 m² in four replicates, were calculated followed by the confidence intervals, considering a 95% significance level.

Comments 2: I would also like to ask you to check and correct the spelling of compounds throughout the manuscript (this applies to subscripts). Please also check and correct the spelling of units, such as kg or gr, for example.  

Response 2: Thank you for pointing to this issue.The spelling of compounds including subscripts ad superscripts were corrected through the text and in tables and figures, except figures 8 and 10 as the excel does not include these functions.

Comments 3: All data in the tables should be given with the same accuracy, so please standardise the data in all tables, e.g. in table 1 EC or N values, in tables 10, 13, 14 and others.  

Response 3: Thank you for pointing to this issue. Accuracy was corrected in all tables.

Comments 4: In my opinion, the economic evaluation of the technology used is missing, especially as this is a typical application study that should give an answer on the economic viability of using the solution proposed in the SEALACOM project. This is so important that the authors refer to lower costs and higher profitability at the end of the application.  

Response 4: Thank you very much for his very important remark. This is the second paper from the SEALACOM project output in agriculture. Indeed, our goal in SEALACOM was to analyze the nexus water-food-energy and evaluate the gaps and means of improvements. We aimed to study the farmer’s attitudes towards new technologies and train the farmers in living lab. Eventually, the economic and social evaluation of the project contribution is an important output and will be the matter of a third paper. The first paper being allocated to the production of protected cucumber (Darwish, T.; Shaban, A.; Faour, G.; Jomaa, I.; Moubarak, P.; Khadra, R. 2024. Transforming Irrigated Agriculture in Semi-Arid and Dry Subhumid Mediterranean Conditions: A Case of Protected Cucumber Cultivation. Sustainability,16 (22), 10050, https://doi.org/10.3390/su162210050

Comments 5: There is also a sentence at the end that refers to information that is not explored in the manuscript, namely farmers' opinions and training. In my opinion, this sentence should be removed.

Response 5: Thank you for this remark. Allow us to keep this sentence to raise curiosity about this issue that will be, hopefully, targeted in the third paper.

4. Response to Comments on the Quality of English Language

Point 1:

Response 1:

5. Additional clarifications

We improved the seamen of research design, questions, hypotheses and methods. Also, we improved the presentation of results, enriched the discussion and redued the conclusion.

Thank you.