Simulation of Soil Water and Salt Balance in Three Water-Saving Irrigation Technologies with HYDRUS-2D

Round 1

Reviewer 1 Report

The manuscript presents results from an interesting study on water and salt dynamics simulation, based on measured data, in cornfield under three irrigation techniques.

I recommend the authors to consider expressing soil salinity as soil saturated paste electrical conductivity, in dS/m, as it is the most common unit of measure for soil EC.

I suggest the authors to include the details regarding the conditions for the soil water and salt simulation with Hydrus 2D (lines 230-234) in the Material and Methods section. 

Further comments are on the attached file.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 1

General comments by Reviewer 1

The manuscript presents results from an interesting study on water and salt dynamics simulation, based on measured data, in cornfield under three irrigation techniques.

1. I recommend the authors to consider expressing soil salinity as soil saturated paste electrical conductivity, in dS/m, as it is the most common unit of measure for soil EC.

Response 1: Thank you for your suggestion. Our original intention is to use soil conductivity as the unit of soil salt content. However, considering that the unit of soil salt content in the literature of soil secondary salinization quoted by us is "%", in order to make readers more directly understand whether our experimental results cause soil secondary salinization. Therefore, we hereby apply to retain the representation of soil salt content in the original text.

2. I suggest the authors to include the details regarding the conditions for the soil water and salt simulation with Hydrus 2D (line 230-234) in the Material and Methods section.

Response 2: Thank you for your suggestion. We introduced the Hydus 2D model in Part 2.3 of the original article. It may be that the title of 2.3 in the original text is easy to be misunderstood by readers, so we have changed "2.3. Mathematical models" to "2.3. Basic equations of the HYDRUS model" in the original text.。Page 3-4, line 172-191 in the revised manuscript with changes marked.

Comments on the attached file.

1. Line124: I suggest the authors to use acronyms for the irrigation methods, such as MDI for mulch drip irrigation; SBDI for shallow buried drip irrigation; and SI for sprinkler irrigation. This will make things easier when presenting and discussing the results.

Response 1: Thank you for your suggestion. We have modified in the manuscript based on your suggestion.

2. Line126: Review the English grammar. It makes no sense to say that the corn "adopted the planting mode of...". Maybe the authors could rewrite the phrase as:"In the mulch drip irrigation technique, the corn was planted in a 'one mulch and two rows' cropping system."

Response 2: Thank you for your suggestion. We have adopted In the Mulch drip irrigation technique, the corn was planted in a 'one Mulch and two rows' cropping system. Page 3, line 137-138 in the revised manuscript with changes marked.

3. Line127: Figure 2a indicates that the width of the mulch was 70 cm.

Response 3: I am sorry that film covering width in the article was written incorrectly. Thank you very much for your comments. We have changed "The width of the mulch was 75 cm." to "The width of the mulch was 70cm.". Page 3, line 139 in the revised manuscript with changes marked.

4. Line129: under shallow buried drip irrigation

Response 4: After our careful inspection, we find that "under" is more accurate than the statement in the original text. Therefore, we have revised it according to your comments. Page 3, line 140-141 in the revised manuscript with changes marked.

5. Line130: Both mulch drip irrigation and shallow buried drip irrigation were performed with the same drip tapes? The details of distance between drip outlets and outflow rate are missing. In the shallow buried drip irrigation method, which pressure was used? Was it different for the mulch drip irrigation?

Response 5: Irrigation technical parameters and other information have been added in the paper，Page 3, line 143-146 in the revised manuscript with changes marked.

6. Line132: The details regarding the distribution, radius and outflow rate of the sprinkler irrigation method are missing.

Response 6: The information of sprinkler irrigation technical parameters has been supplemented in the paper，Page 3, line 147-148 in the revised manuscript with changes marked.

7. Line142-143: If 100 ml of water was added to 20g of soil, it would mean a soil to water ratio of 1:5, not water to soil ratio.

Response 7: I am sorry for the writing error in the article, we have corrected the error in the manuscript. Page 4, line 160-161 in the revised manuscript with changes marked.

8. The corn field was fertigated? When did the fertility period occurred?

Response 8: We have added the total amount of fertilization in the growth period, times and amount of fertilizer applied each time at the end of section 2.1. Page 3, line 148-151 in the revised manuscript with changes marked.

9. There was also cotton crops in the experiment? It was not mentioned before.

Response 9: Sorry, this was a clerical error and we have changed "Cotton" to "corn" in the manuscript. Please check and revise the Page 4, line 169 in the manuscript.

10. These details regarding fertigation should be given in the 2.1 section, where the cropping conditions were detailed. Instead of kg/hm², I suggest the authors to use kg/ha.

Response 10: We change all "kg/hm²" to "kg/ha", and the details regarding fertigation have been changed into the 2.1 section. Please check and revise the Page 3, line 148-151 in the manuscript

Author Response File: Author Response.docx

Reviewer 2 Report

Comments:

In the work “Simulation of soil water and salt balance in three water-saving irrigation technologies with HYDRUS-2D” (agronomy-2116989), the authors have tried to simulate soil water and salt fluctuations subjected to three water managements, i.e., mulch drip irrigation, shallow buried drip irrigation, and sprinkler irrigation, by using a HYDRUS-2D model. The study is interesting and falls within the journal's scope well. Unfortunately, some crucial information is missing and the writing is hard to follow. The experimental design may be flawed, the manuscript cannot be accepted in a decent journal, Agronomy, in its current form. My concerns may be useful in their revised manuscript.

Major issues:

i. 0.1% seems to be a crucial indicator for the study, which is, apparently not a “one-size-fits-all” number, especially for this study. The authors should provide convincing evidence for the reasons for choosing this exact number.

ii. The writing is hard to follow, and careful proofreading is badly needed (or by a native speaker), e.g., line 14; line 331; line 373, and many other weird sentences in the text.

iii. The significance of the study is not convincing, e.g., the meaningful results for sustainable developments are good (line 46; line 73), can you give more words on this point? It would be intriguing for the readers if the authors could put the significance into China’s sustainability (Applying Humboldt’s holistic perspective in China’s sustainability. Geography and Sustainability 2: 123–126. https://doi.org/10.1016/j.geosus.2021.06.001).

iv. China is huge, a small point (i.e., the study site) in a big nation is weird. A zoom-in geographic site is suitable rather than showing a big nation (cf. Figure 1; Establishing an ecological forest system of salt-tolerant plants in heavily saline wasteland using the drip-irrigation reclamation method. Agricultural Water Management 245: 106587. https://doi.org/10.1016/j.agwat.2020.106587), or just delete figure 1.

v. Figure 2 is a good revenue to show the three water irrigation methods, but I cannot see its function. The figure 2 must be shown in an understandable way.

vi. In this study, the simulation period is 5 years, which is a “safe window” to see the irrigation influences on soil salinization, the possible consequences might be seen in 15 years for some plant species (they cited. Soil salinization after long-term mulched drip irrigation poses a potential risk to agricultural sustainability. European Journal of Soil Science, January 2019, 70: 20–24. https://doi.org/10.1111/ejss.12742), thus, the authors concluded that “the risk of secondary salinization is minimal if irrigation is reasonable” is NOT reasonable. I suggest the authors extend the modeling duration 15 years or 2-3 decades.

Small points:

Line 19: HYDRUS-2D or Hydrus model?

Line 94: what do you mean “minor studies have been….”? Few? Very few?

Line 107: 2.1. Overview of the study area, potential evapotranspiration or pan evaporation is vital to know the drought of your study, the data should be shown here.

Line 157-189: the mathematical models are a mess. The mathematical should be written beautifully in a mathematical language, i.e., simplification and concise.

Line 185: S, the amount of water uptake by plants, is a crucial module of the model, the data may be shown in the text directly.

Line 215: “soil moisture” or “soil water content”? choose one.

Line 261-263: “Soil salt mainly accumulated at the edge of wet soil, resulting in the distribution of low soil salt inside the mulch and high soil salt between the mulches.”, a good point, I believe it’s not the first discovered, citations? The result seems be contrary to a recent study in which the authors reported: “low salinity zones formed quickly under drip emitters and the average electrical conductivity of saturated soil paste extracts within 60 cm depth….” (Establishing an ecological forest system of salt-tolerant plants in heavily saline wasteland using the drip-irrigation reclamation method. Agricultural Water Management 245: 106587. https://doi.org/10.1016/j.agwat.2020.106587). And temporal variations in soil salt in real-world may be highlighted in the discussion (Variations of Soil Salinity and Cotton Growth under Six-Years Mulched Drip Irrigation. 2021, 11: 1127. https://doi.org/10.3390/agronomy11061127). Can you fix this?

Line 278-279: A threshold value for salinization, 0.1% in this study, which was cited many times in the text, but only showed the source here (and wrong citation style!), that's weird.

Author Response

Response to Reviewer 2

Comments:

In the work “Simulation of soil water and salt balance in three water-saving irrigation technologies with HYDRUS-2D” (agronomy-2116989), the authors have tried to simulate soil water and salt fluctuations subjected to three water managements, i.e., mulch drip irrigation, shallow buried drip irrigation, and sprinkler irrigation, by using a HYDRUS-2D model. The study is interesting and falls within the journal's scope well. Unfortunately, some crucial information is missing and the writing is hard to follow. The experimental design may be flawed, the manuscript cannot be accepted in a decent journal, Agronomy, in its current form. My concerns may be useful in their revised manuscript.

Major issues:

1. 0.1% seems to be a crucial indicator for the study, which is, apparently not a “one-size-fits-all” number, especially for this study. The authors should provide convincing evidence for the reasons for choosing this exact number.

Response: In the article published in the Journal of Geosraphical Sciences by LIU et al., 2001, Table 1 clearly shows that when the Salt content in soil surface (%) is between 0.1-0.3%, the soil is defined as mildly salinized. Therefore, we also use 0.1% as the evaluation standard to analyze the evolution of soil salinity under different irrigation technology conditions. At the same time, we have also added citation sources in the text, please check L325-L328 of the revised manuscript.

1. The writing is hard to follow, and careful proofreading is badly needed (or by a native speaker), e.g., line 14; line 331; line 373, and many other weird sentences in the text.

Response: The part of our article where the sentence meaning is unclear has been

modified (line 16-19, line 22-24, line 39-42, line 43-49, line72-78, line 99-109, line 136-151, line 174-193, line 266-269, line278-282, line 323-328, Line 352-356), and Editage was asked to polish the language of the article, and the proof of polishing is shown in the figure below.

iii. The significance of the study is not convincing, e.g., the meaningful results for sustainable developments are good (line 46; line 73), can you give more words on this point? It would be intriguing for the readers if the authors could put the significance into China’s sustainability (Applying Humboldt’s holistic perspective in China’s sustainability. Geography and Sustainability 2: 123–126. https://doi.org/10.1016/j.geosus.2021.06.001).

Response: We have revised the introduction in the text, and thank you for the references, please check line 43-49, line72-78, line 99-109 of the revised manuscript.

106587. China is huge, a small point (i.e., the study site) in a big nation is weird. A zoom-in geographic site is suitable rather than showing a big nation (cf. Figure 1; Establishing an ecological forest system of salt-tolerant plants in heavily saline wasteland using the drip-irrigation reclamation method. Agricultural Water Management 245: 106587. https://doi.org/10.1016/j.agwat.2020.106587), or just delete figure 1.

Response: We have revised Figure 1, please check Page 14，line 498 in the revised manuscript.

1. Figure 2 is a good revenue to show the three water irrigation methods, but I cannot see its function. The figure 2 must be shown in an understandable way.

Response: Thank you for your suggestion. I am very sorry that Figure 2 is a schematic diagram of the field layout and root sampling of the three irrigation technologies in actual production. Figure 4 is an abstract schematic diagram of the boundary construction of the model, which more intuitively shows the boundary conditions of the water-salt transport model.

24. In this study, the simulation period is 5 years, which is a “safe window” to see the irrigation influences on soil salinization, the possible consequences might be seen in 15 years for some plant species (they cited. Soil salinization after long-term mulched drip irrigation poses a potential risk to agricultural sustainability. European Journal of Soil Science, January 2019, 70: 20–24. https://doi.org/10.1111/ejss.12742), thus, the authors concluded that “the risk of secondary salinization is minimal if irrigation is reasonable” is NOT reasonable. I suggest the authors extend the modeling duration 15 years or 2-3 decades.

Response: Thanks to your comments and the provided literature, we changed the simulation period to 20 years (Figures 6d, 7d, 8d, 9a, 9b, 9c). However, the results were basically unchanged. The experimental area of the reference you provided is an arid area, and they believe that soil salinization after long-term drip irrigation poses a potential risk to agricultural sustainability (Wang et al., 2019). The main reason is that the irrigation water source in this experiment area is not brackish water, but in the case of groundwater and irrigation water salinization in arid areas (Liu et al., 2012), the main factors affecting the long-term drip irrigation soil salinization in this area The problem is irrigation water quality (Li et al., 2012). Therefore, in order to answer your question more fully, under the experimental conditions, we set the salinity of irrigation water at 2 g/L, 3 g/L and 5 g/L for simulation. The result is shown in the figure below. The simulation results show that when the salinity of brackish water is 0g/L. As the simulation time increases, the salt content of the soil surface (5cm) remains stable and the value is very low (7.7335 Kg/ha); however, as the simulation time increases, the salt content of the soil surface layer tends to increase under different salinity conditions. Nearly stable; and with the increase of the salinity of irrigation water, the salinity of the soil surface layer increases at the end of each year; when the salinity of brackish water is 5g/L, the 5g/L irrigation water, the amount of salt accumulated on the soil surface reached 1684.34kg/ha (0.2246%), exceeding the salinization threshold, and it is also considered that there is a risk of soil salinization. At the same time, the simulation results are also in line with the conclusion that Kang et al. (2010) found that the salt content of the field soil layer increased in the early stage of drip irrigation, and the soil salinity tended to be stable in the later stage when they used brackish water to conduct drip irrigation of waxy corn under plastic film.

However, this test area is located in the West Liaohe Plain, where the buried depth of shallow groundwater is greater than 10m, and the total salinity is less than 0.5g/L. Especially in the experiment location, the total salinity of groundwater is negligible. Therefore, the risk of secondary salinization of local drip irrigation is very small. Moreover, according to the survey of the test site this year, the current drip irrigation (the seventh year) of corn is running well, and there is no sign of secondary salinization of the soil.

Liu, M.; Yang, J.; Li, X.; Yu, M.; Wang, J. (2012). Effects of irrigation water quality and drip tape arrangement on soil salinity, soil moisture distribution, and cotton yield (Gossypium hirsutum L.) under mulched drip irrigation in Xinjiang, China. Journal of Integrative Agriculture, 11, 502–511.

Li Mingsi, Liu Hongguang, Zheng Xurong. Spatiotemporal variation for soil salinity of field land under long-term mulched drip irrigation[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2012, 28(22): 82－87. (in Chinese with English abstract)

Wang, Z.; Fan, B.; Guo, L. (2019). Soil salinization after long-term mulched drip irrigation poses a potential risk to agricultural sustainability: soil salinization under mulched drip irrigation. European Journal of Soil Science, January, 70: 20–24.

Kang Y, Chen M, Wan S. Effects of drip irrigation with saline water on waxy maize (Zea mays L. var. ceratinaKulesh) in North China Plain. Agricultural Water Management, 2010, 97(9): 1303－1309.

Figure Effect of different concentrations of irrigation water on the salt content of the soil surface (5cm)

Small points:

Line 19: HYDRUS-2D or Hydrus model?

Response: Thanks for the reminder, we have revised to HYDRUS-2D, please see line 19 of the revised manuscript.

Line 94: what do you mean “minor studies have been….”? Few? Very few?

Response: We have revised the inappropriate expressions in the article, please check line 104-109 of the revised manuscript.

Line 107: 2.1. Overview of the study area, potential evapotranspiration or pan evaporation is vital to know the drought of your study, the data should be shown here.

Response: Thanks, we adjusted the transpiration data to section 2.1 and revised the relevant figure numbers. Page 3, line 129 and Page18, line 513 in the revised manuscript with changes marked.

Line 157-189: the mathematical models are a mess. The mathematical should be written beautifully in a mathematical language, i.e., simplification and concise.

Response: Thank you for your suggestion. Page 4, line 174-193 in the revised manuscript with changes marked.

Line 185: S, the amount of water uptake by plants, is a crucial module of the model, the data may be shown in the text directly.

Response: Thank you for your suggestion. Soil root system model parameters are shown in Table 3, and the values is shown in Figure 5.

Line 215: “soil moisture” or “soil water content”? choose one.

Response: We choose to use "soil water content" to express the soil water content, please check the Page 6, line 216 and entire manuscript.

Line 261-263: “Soil salt mainly accumulated at the edge of wet soil, resulting in the distribution of low soil salt inside the mulch and high soil salt between the mulches.”, a good point, I believe it’s not the first discovered, citations? The result seems be contrary to a recent study in which the authors reported: “low salinity zones formed quickly under drip emitters and the average electrical conductivity of saturated soil paste extracts within 60 cm depth….” (Establishing an ecological forest system of salt-tolerant plants in heavily saline wasteland using the drip-irrigation reclamation method. Agricultural Water Management 245: 106587. https://doi.org/10.1016/j.agwat.2020.106587). And temporal variations in soil salt in real-world may be highlighted in the discussion (Variations of Soil Salinity and Cotton Growth under Six-Years Mulched Drip Irrigation. 2021, 11: 1127. https://doi.org/10.3390/agronomy11061127). Can you fix this?

Response: First, thank you for giving us the opportunity to study the literature.

After our inspection, we found that our conclusion does not conflict with the first literature you mentioned. The drip irrigation under the film in our experiment belongs to the local irrigation technology, and its wetted width and wetted depth are the main design parameters of this technology. The wet width is mainly to make the soil under the film wet as a whole, and at the same time, it can move the soil salt to the bare land outside the film, as to ensure that the water and salt environment of the soil under the film is suitable for the growth of crops. This is also part of the conclusions cited in this article (Zheng et al., 2009; Liu et al., 2013); in addition, the design of the wetting depth will be set according to the growth depth of the crop roots at different growth stages. In the literature you provided It shows that the 0-60cm soil below the dripper decreases rapidly (Dong et al., 2021). In order to ensure that the root growth in the soil under the film is not stressed by water and salt, the drip irrigation under the film does not only include the horizontal direction, also including the part below the root layer in the vertical direction，In other words, the reduction of soil salinity under the film will also occur in the results of this experiment. This part of the conclusion is not the research focus of this paper. This paper mainly takes the change of soil salinity in 0-5cm as the research object, and analyzes the influence of different irrigation techniques on the evolution of soil salinity. In order to make readers understand the intention of this article more clearly, we have added a reference to this part of the article, please check the line 258-262 in the revised manuscript.

Regarding the second document you mentioned (Li et al., 2021), the article introduces the changes in soil salinity and cotton yield in 6 years, but notices that the irrigation amount in this article is set between 730-826mm/Year , is much higher than the recommended irrigation amount (320mm/year) published by Ning et al. (2021) on agricultural water management, and the soil salinity is fully leached, so it is concluded that the soil salinity of the drip irrigation under the mulch gradually decreases. The mathematical simulation is to obtain the dynamic change process of soil water and salt under different irrigation technology conditions. At the same time, some literature results are cited to support the simulation conclusion of this paper. I hope the above explanation can be recognized by you, thank you!

Zheng, Z.; Zhang, F.; Ma, F.; Chai, X.; Zhu, Z.; Shi, J.; Zhang, S. (2009). Spatiotemporal changes in soil salinity in a drip-irrigated field. Geoderma 149, 243e248. http://dx.doi.org/10.1016/j.geoderma.2008.12.002.

Liu, M.; Yang, J.; Li, X.; Liu, G.; Yu, M.; Wang, J. (2013). Distribution and dynamics of soil water and salt under different drip irrigation regimes in northwest China. Irrig. Sci. 31, 675–688. https://doi.org/10.1007/s00271-012-0343-3.

Ning, S.; Zhou, B.; Shi, J.; Wang, Q. (2021). Soil water/salt balance and water productivity of typical irrigation schedules for cotton under film mulched drip irrigation in northern xinjiang. Agricultural Water Management, 245. https://doi.org/10.1016/j.agwat.2020.106651

Line 278-279: A threshold value for salinization, 0.1% in this study, which was cited many times in the text, but only showed the source here (and wrong citation style!), that's weird.

Response: We have supplemented the citation in the article, please check line 328 of the revised manuscript.

Liu, H.; Xu, J.; Xu, X. (2001). Present situation and tendency of saline-alkali soil in west Jilin Province. Journal of Geosraphical Sciences, 11(3): 321-328. https://doi.org/10.1007/BF02892316

Author Response File: Author Response.docx

Reviewer 3 Report

Comments

Title:   Simulation of soil water and salt balance in three water-saving  irrigation technologies with HYDRUS-2D

No: agronomy-2116989

General comments

In present study mulch drip irrigation technology  was used  to solve the problem of insufficient temperature accumulation during the pre-fertility period. The study investigate the impact of drip irrigation technology on the water and salt environment of farmland.  The study described the  corn cultivation and simulated the water and salt changes of farmland under mulch drip irrigation, shallow buried drip irrigation, and sprinkler irrigation with variable rainfall and initial salt content using the Hydrus model. The results showed that the distribution and variation of water and salt in soil were similar under mulch drip irrigation and shallow buried drip irrigation. The change near the drip irrigation tape was mainly affected by irrigation itself. The water and salt in soil between drip irrigation tapes were not only affected by irrigation, but also closely related to rainfall. With the decrease of rainfall, the amount of salt in the soil surface (5 cm) had an increasing trend. With an initial soil salinity of 0.1%, the salinity of the surface soil under mulch drip irrigation was significantly higher than that under shallow buried drip irrigation and sprinkler irrigation within two years.The paper is interesting and it is suitable for publishing in the Journal. Following are the major weakness.

1. English should be revised.

2. More scientific references are needed on the topic. Please see some of latest reputed references on this topic.

- Kumar, R., Qureshi, M., Vishwakarma, D.K., Kuriqi, A., Elbeltagi  A., and Saraswat, A. (2022). Evolution of emerging water contaminants and removal technology for sustainability. Case Studies in Chemical and Environmental Engineering, https://doi.org/10.1016/j.cscee.2022.100219.

- Kumar, R. and Haroon, S. (2021).Water requirement and fertigation in high density planting of apples. Indian  J. Hort. 78(3), 292-297, DOI : 10.5958/0974-0112.2021.00042.6

3. The authors should clearly emphasize the novelty and originality of the paper compared with the availableliterature.

4. Author explain more about input parameters of Hydrus model

5.  Modify introduction section

6. Rephrase conclusion section

7. What is new in this study? 

 In my opinion, the paper can be accepted and published only after major revision and satisfactory reply/ modification of information and explanations of the raise points in revised version of manuscript.

Comments for author File: Comments.docx

Author Response

Response to Reviewer 3

Comments

Title: Simulation of soil water and salt balance in three water-saving irrigation technologies with HYDRUS-2D

No: agronomy-2116989

General comments

In present study mulch drip irrigation technology was used to solve the problem of insufficient temperature accumulation during the pre-fertility period. The study investigate the impact of drip irrigation technology on the water and salt environment of farmland. The study described the corn cultivation and simulated the water and salt changes of farmland under mulch drip irrigation, shallow buried drip irrigation, and sprinkler irrigation with variable rainfall and initial salt content using the Hydrus model. The results showed that the distribution and variation of water and salt in soil were similar under mulch drip irrigation and shallow buried drip irrigation. The change near the drip irrigation tape was mainly affected by irrigation itself. The water and salt in soil between drip irrigation tapes were not only affected by irrigation, but also closely related to rainfall. With the decrease of rainfall, the amount of salt in the soil surface (5 cm) had an increasing trend. With an initial soil salinity of 0.1%, the salinity of the surface soil under mulch drip irrigation was significantly higher than that under shallow buried drip irrigation and sprinkler irrigation within two years. The paper is interesting and it is suitable for publishing in the Journal. Following are the major weakness.

1. English should be revised.

Response 1: Thank you for your suggestion. Editage was asked to polish the language of the article and the proof of polishing is shown in the figure below.

2. More scientific references are needed on the topic. Please see some of latest reputed references on this topic.

Response 2: Thank you for your suggestion. We have cited some latest reputed references.

Bo, X.; Li, Y.; Li, J. (2021). Response of productivity and nitrogen efficiency to plastic-film mulching patterns for maize in sub-humid northeast china. Irrigation Science, 39(2): 251-262.

Guan Changkun; Ma Xianlei; Shi Xiaoping. 2022. The impact of collective and individual drip irrigation systems on fertilizer use intensity and land productivity: Evidence from rural Xinjiang, China. Water Resources and Economics, 38: 100196. https://doi.org/10.1016/j.wre.2022.100196.

He, Q.; Li, S.; Kang, S.; Yang, H.; Qin, S. (2018). Simulation of water balance in a maize field under film-mulching drip irrigation. Agricultural Water Management, 210: 252-260.

Hu, Y.; Li, X.; Jin, M.; Wang, R.; Chen, J.; Guo, S. (2020). Reduced co-occurrence and ion-specific preferences of soil microbial hub species after ten years of irrigation with brackish water. Soil and Tillage Research, 199: 104599

Jia, H.; Qian, H.; Zhang, L.; Feng, W.; Wang, H. Gao, Y. (2020). Alterations to groundwater chemistry due to modern water transfer for irrigation over decades. The Science of the Total Environment, 717: 137170.1-137170.15.

Kisi, O.; Khosravinia, P.; Heddam, S.; Karimi, B.; Karimi, N. (2021). Modeling wetting front redistribution of drip irrigation systems using a new machine learning method: adaptive neuro-fuzzy system improved by hybrid particle swarm optimization - gravity search algorithm. Agricultural Water Management, 256: 107067.

Li, W.H., Wang, Z.H., Zhang, J.Z., Zong, R., 2021b. Soil salinity variations and cotton growth under long-term mulched drip irrigation in saline-alkali land of arid oasis. Irrig. Sci. 40, 103–113

Meng, C.; Yan, L.; Zhang, S.; Wei, C. (2017). Variation of Soil Salinity in Plow Layer of Farmlands under Long-term Mulched Drip Irrigation in Arid Region. Acta Pedologica Sinica, 54(6): 1386-1394. (In Chinese).

Ning, S.; Zhou, B.; Shi, J.; Wang, Q. (2021). Soil water/salt balance and water productivity of typical irrigation schedules for cotton under film mulched drip irrigation in northern Xinjiang. Agricultural Water Management, 245: 106651.

Shareef, M.; Gui, D.; Zeng, F.; Waqas, M.; Zhang, B.; Iqbal, H. (2018). Water productivity, growth, and physiological assessment of deficit irrigated cotton on hyperarid desert-oases in northwest china. Agricultural Water Management, 206: 1-10.

Thidar, M., Gong, D., Mei, X., Gao, L., Li, H., Hao, W., Gu, F., 2020. Mulching improved soil water, root distribution and yield of maize in the loess plateau of Northwest China. Agric. Water Manag, 241. https://doi.org/10.1016/j.agwat.2020.106340.

Wang, J.; Du, G.; Tian, J.; Zhang, Y.; Jiang, C.; Zhang, W. (2020). Effect of irrigation methods on root growth, root-shoot ratio and yield components of cotton by regulating the growth redundancy of root and shoot. Agriculture Water Management, 234: 106120.

Wang, N.; Chen, H.; Ding, D.; Zhang, T.; Li, C.; Luo, X.; Chu, X.; Feng, H.; Wei, Y.; Siddique, K. (2022). Plastic film mulching affects field water balance components, grain yield, and water productivity of rainfed maize in the Loess Plateau, China: A synthetic analysis of multi-site observations. Agricultural Water Management, 266: 107570.

Wang, Z.; Fan, B.; Guo, L. (2019). Soil salinization after long-term mulched drip irrigation poses a potential risk to agricultural sustainability: soil salinization under mulched drip irrigation. European Journal of Soil science, 70(1): 20-24.

Wang, Z.; Yin, G.; Gu, J.; Wang, S.; Ma, N.; Zhou, X.; Liu, Y.; Zhao, W. (2022). Effects of Water, Nitrogen and Potassium Interaction on Water Use Efficiency of Spring Maize Under Shallow-buried Drip Irrigation. Journal of Soil and Water Conservation, 36(4): 316-324. (In Chinese).

Xiao, C.; Li, M.; Fan, J.; Zhang, F.; Li, Y.; Cheng, H.; Li, Y.; Hou, X.; Chen, J. (2021). Salt leaching with brackish water during growing season improves cotton growth and productivity, water use efficiency and soil sustainability in Southern Xinjiang. Water, 13(18): 2602.

Zhang, Y.; Li, X.; Šimůnek, J.; Shi, H.; Chen, N.; Hu, Q.; Tian, T. (2021). Evaluating soil salt dynamics in a field drip-irrigated with brackish water and leached with freshwater during different crop growth stages. Agricultural Water Management, 244: 106601.

3. The authors should clearly emphasize the novelty and originality of the paper compared with the available literature.

Response 3: Thank you for your suggestion. We revised the manuscript according to your suggestion. Page 3, line 103-115 in the revised manuscript with changes marked.

4. Author explain more about input parameters of Hydrus model

Response 4: Thank you for your suggestion. We revised the manuscript according to your suggestion. Page 4-5, line 174-193 in the revised manuscript with changes marked.

5. Modify introduction section

Response 5: Thank you for your suggestion. We have revised the Introduction section. Page 2-3, line 39-42, line 43-49, line72-78, line 99-109 in the revised manuscript with changes marked.

6. Rephrase conclusion section

Response 6: Thank you for your suggestion. We have revised the conclusion section. Page 7-8, line 348-350, line 352-356, line359-360, line 365-366 in the revised manuscript with changes marked.

7. What is new in this study?

Response 7: Thank you for your suggestion. We divide the salinity of 0-5cm soil layer into the main research object, take mild soil salinization (0.1%) as the evaluation index, and use the method of combining experiment and numerical simulation to analyze the evolution process of soil salinity under different irrigation technology conditions for 20 years. And finally put forward a suitable irrigation strategy, therefore, we think this article has some new ideas, and hope to get your approval, thank you!

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

I consider that the authors have done the changes necessary to the original manuscript. However, I still think that the authors should refer to soil salinity as electrical conductivity, which is the most used method in agriculture to measure soil primary salinity levels and soil salinization due to agricultural practices.

The argument of the authors regarding easier perception by readers for the changes regarding secondary salinization could be contemplated by showing soil salinity as EC and the difference between initial and final EC values in percentage.

Author Response

Response to Reviewer 1

Thank you so much for your comments on this manuscript. We have read the paper carefully and made the following modifications:

Comments and Suggestions by Reviewer 1

I consider that the authors have made the changes necessary to the original manuscript. However, I still think that the authors should refer to soil salinity as electrical conductivity, which is the most used method in agriculture to measure soil primary salinity levels and soil salinization due to agricultural practices.

The argument of the authors regarding easier perception by readers for the changes regarding secondary salinization could be contemplated by showing soil salinity as EC and the difference between initial and final EC values in percentage.

Response: Thanks for your suggestion. Based on your comments, we have added the standard curve and the formula between soil salt content and electrical conductivity in Figure 4. Also, the description of the salt salinity in the whole paper is modified as EC value (highlighted in blue).

Author Response File: Author Response.docx

Reviewer 2 Report

The authors seem to have done good work in revising the manuscript and I think it can be accepted for publication in the journal. I have no further comments now, cheers!

Author Response

Thank you for your recognition and encouragement of our work.