Crop Water Requirements and Irrigation Schedules for Some Major Crops in Southern Iraq

Round 1

Reviewer 1 Report

Water-441245-v1 manuscript “Crop water requirements and irrigation schedules for some major crops in Southern Iraq”

Reviewer’s comments

This article is a case study of irrigation planning in Iraq, with a classical approach and presentation, applying common management procedures for calculating irrigation water requirements and schedules. Iraq conditions for cropping and irrigation look quite similar to other countries in the Mediterranean semi-arid regions. Therefore, the article does not present any methodological or scientific innovation, besides the interest of the case study. In my opinion, it can be published after some minor revisions.

1 – English should be revised and edited, which may make the text clearer in some points.

2 – The authors conclude that the FAO CROPWAT model they used is the best for the article’s purposes of calculating irrigation water requirements and irrigation schedules. The conclusion is not valid, because no other models were used for comparison. Namely, FAO also proposes, with the same irrigation planning objectives, the AquaCrop model, newer and in principle innovative in relation to CROPWAT, also being available online in the FAO internet site. A reference and some comment by the authors should at least be done in this context.

3 – Evapotranspiration is commonly represented by ETo. In this paper, sometimes it is ETo, in others it is ET0. Homogeneity is required.

4 – Crop yields (biomass and agronomical or economical) are never referred to in this paper. However, it should be, as helpful information, completing data on water requirements by the crops, as very good decision support “elements” for the farmers and irrigation management authorities.

5 – Figure 1 is a map without scale and other geographical references (on the map).

6 – In line 59, “metrological” should be “meteorological”.

7 – In line 110, deriving equation (2) eliminated r_s and r_a, surface and aerodynamic resistances, respectively, which could be used for consideration of the CO2 contents in the atmosphere. Such a consideration could be helpful for authorities’ decisions, managing irrigation in the context of climate change … The following reference could be a starting one: Islam et al (2012) – Modeling the effect of elevated CO2 and climate change on reference evapotranspiration in the semi-arid central Great Plains. Transations of the ASABE, vol 55(6), 2135-2146. DOI 10 13031/2013 42505.

8 – Please revise information (in the Abstract) on gross and net irrigation requirements for potato (both 44.6, which would make irrigation efficiency 100%).

Author Response

Dear Reviewer

Thank you very much for your comments that improved our paper.

With response to your comments we did the following:

1-              English proofread.

2-              Point removed from conclusion.

3-              ET0 were corrected to ET0 in many places in the paper.

4-              Some information and table 11 about crop yields were added at the end of the paper.

5-              The map is changed.

6-              Metrological was corrected to meteorological in line 60 and line 80.

7-              Note in line 110 has been used.

8-              The information in the abstract (line 24 and 25) was revised.

Thank you again.

Nadhir Al-Ansari

Corresponding Author

Author Response File: Author Response.pdf

Reviewer 2 Report

The article analyzes an interesting and important topic for the successful management of water for agricultural use. Although it is not the shortage of water that affects the territory of study, but it is necessary to be efficient and effective with the use of water resources to have a sustainable agriculture.

The CROPWAT program seems to be a very appropriate tool for policy-makers and those persons who have to make decisions on the allocation and use of water resources, however, it is not suitable for the farmer without technical advice, due to the amount of data that is needed for your application.

Undoubtedly, the use of software to help determine water saving levels in the face of climate change problems is a very appropriate issue. However, in order to determine the advantage that such a program represents in a cultivated area, it would be advisable to accompany it with a more in-depth study for the agricultural sector of the area: as an adequate  selection of crops, based on its importance in the cultivation of area; the innovations that have been introduced in recent years; the strong increase in consumption, etc., or simply, the argument could be focused on the decrease in irrigation water consumption that would be obtained when the programma Cropwat is use. None of it is incorporated into the work for adequate justification.

On the other hand, this work lacks:

1. A greater description of irrigation programs, why are two programs for wheat and barley and 16 for potatoes and 17 for tomato?

2. Further explanation of figures 1,2,3,4, there are lines of green and brown color that do not present references, what do you want to indicate with them?

3. further discussion of the results,

4. more explanation of the results,

The interest of the work would increase considerabl, perhaps, if the work had been raised with a comparative analysis between the initial and final situation to determine the consumption of water of these crops, before the application of the software and the final situation to detect the savings or efficiency in the consumption of irrigation water in the different crops, so that the interest of the work would increase considerably and the results would be discussed with more enthusiasm.

There are certain errors that have to be corrected

• in table 1, the harvest date of wheat and barley is matched.

• Between lines 197 - 200, you have to review the data, there is no coincidence with the data shown in their corresponding tables.

Author Response

Dear Reviewer

Thank you very much for your comments that improved our paper.

With response to your comments we did the following:

1-    Paragraphs about (the agricultural sectors of the area) were added between line 238 and line 260.

2-              The work lacks:

1.                      It was noted that the number of irrigation programs for each crop is calculated by CROPWAT program according to several factors of the plant, soil and weather conditions.

2.                      All the figures (2, 3, 4, 5) have been changed and there is now (within each figure) an explanation of the meaning of the colored lines.

3.                      Paragraphs (about 22 lines) were added to the end of the research to discuss and explain the results.

4.                      Wheat and barley are grown at the same time in Iraq, around 15 November.

5.                      The data between lines 202 and 205 was corrected.

In addition, we corrected the first email, and some spelling and arithmetic errors were corrected in different places of this research, some words were deleted / added in different places.

Thank you again.

Nadhir Al-Ansari

Corresponding author

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

If the authors consider that wheat and barley have the same productive cycle, because tables 3 and 4 have different time intervals.

The conclusions are still somewhat poor.

Author Response

Thank you very much for your comments.

Please note the following:

The data in table 3 and table 4 is generated by the CROPWAT software after entering this data:  station name, the climate data, soil data and the planting date (the same for wheat and barley), the software calculates different harvesting date for each plant due to the variation between plants.

4. Conclusions

Using the FAO CROPWAT 8.0 model yielded an interesting result. It can readily be seen that; crop water requirements and schedules were local specific owing to the seasonal and ecological features of the province. Summer crop (tomato) had higher amounts of evapotranspiration, water requirements, and irrigation schedules than the other three crops following this order:

Tomato > wheat > white corn > barley

 The study results enhance understanding the water requirements which will consequently help improve the management of water resources and the productivity through policies based on these findings and can be used by the farmers to select the quantity and frequency of crop irrigation water

Therefore, this study shows a more important indication that the CROPWAT irrigation management model could be used to estimate agricultural water requirements with different crops effectively and efficiently. This will facilitate the efforts to meet water shortage and the changes of irrigation management.

Thank you again.

Best regards.

Corresponding author

Author Response File: Author Response.docx