Soil Salinity Prediction Using Remotely Piloted Aircraft Systems under Semi-Arid Environments Irrigated with Salty Non-Conventional Water Resources
, Pedro Pérez Cutillas 2, Faissal Aziz 3,4, Marina Llobet Escabias 5, Harm Boesveld 5, Harm Bartholomeus 6 and Anas Tallou 4
Round 1
Reviewer 1 Report
Title: Soil salinity prediction using remote sensing under semi-arid environments irrigated with salty non-conventional water resources
The authors predicted soil salinity using salinity NDSI and NDVI from UAV imaginary in Murcia. The results show that the SI and canopy temperature perform well for soil salinity prediction. Research is interesting and the UAV is promising method for agricultural experiments. I suggest only minor modification is needed before acceptance. The comments are below:
1. For the title, the concept of remote sensing includes diverse platforms. I suggest modify it into Unmanned Aerial Vehicle.
2. Lines 139-144, soil sample was taken on the specific days. These soil samples are from soil surface or from specific soil depths like 5cm or 10cm?
3. In 2.6.1, please show equations of SI, NDSI, NDVI.
Author Response
The responses are on the attached file. Thanks for the inputs.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Manuscript "Soil salinity prediction using remote sensing under semi-arid environments irrigated with salty non-conventional water resources" isn't recommend for publication in Agronomy journal.
The manuscript idea has merit as concerns about the impact of soil salinity on vegetable production and the overall design of the experiments and measurements are logical and make sense, but there is a need some additional information in the methods section and result. Some information is missing and some need correction in order to make the manuscript and its results easier to understand.
Detailed comments are presented in the order of their occurrence in manuscript using line numbering.
1. Methods of citing literature in the manuscript text is inconsistent with the requirements of the MDPI publisher. Need correction.
2. Species Latin name should be Italized (Lactica Sativa var. romanica) Line 112.
3. Lines 128-129 In commercial plot "Rainfall, wastewater, and groundwater were put together to form the irrigation water, which was then applied via a drip irrigation system." Whether the lettuce cultivation was carried out under cover or in the open air (as mentioned on 2.3. subchapter. If in the open air, how was water from rainfall collected from more than 1 ha?
Line 146 need correction not 100C should be 100oC.
Line 179 Incorrect notation of chemical symbols instead F-, Cl-, NO2-, Br-, NO3-, PO43-, SO42- should be F-, Cl-, NO2-, Br-, NO3-, PO43-, SO42-
Line 179 correct list of the cations and remove F-, Cl-, NO2-, Br-, NO3-, PO43-, and SO42-
More precise information about collection of irrigation water is needed. Line 181-185
Line 199 please correct and instead 60oC should be 60oC
Section Results.
In manuscript no data on lettuce parameters from measurement T1, T2, T3. On the basis of which table (or figure) there is a detailed description of the weight, diameter and height of lettuce in chapter 3.1.1. Visual assessment and lettuce characteristics.
In lines 202-205 listed leaf mineral compounds N, C, F-, Cl-, NO2-, Br-, NO3-, PO43-, and SO42-, Al, As, Be, Bi, B, Ca, Cd, Co, Cr, Cu, Fe, K, La, 204 Li, Mg, Mn, Mo, Na, Ni, Pb, P, Rb, Sb, Se, S, Sr, Ti, Tl, V and Zn). In table 1 only content of N, C, Ca, Fe, Cl, Na presented. For what purpose the others mineral compounds were analyzed?
Table 1 Mineral content of dried leaves presented per 1 kg of dry weight? If yes please explain how it is possible that e.g. at T1 (12/11/2019) in CP treatment had a total of 1194.27 g of N, C, Ca, Fe, Cl, and Na per 1 kg of leaves dry weight. The same remark applies to the treatment of SP on T1 and the term T2.
Line 265-266 Sentence need correction. The salt content by ECsat presented in two very different value 7.04 0.82 dS/m?
Line 338 Last chemical analyses carried out at harvest T5. Why the Authors report a significant decreased after lettuce harvesting?
Table 2. Explanation need 1084.86 g of Fe per kg dry weight.
Line 346 No table 4 in the manuscript.
Line 361 No figure 6 in the manuscript.
Repeat figure 1.
Additional remarks to result section.
The full chemical composition of the irrigated water was not included in the commercial experiment. No water chemical composition in greenhouse tests presented.
No soil chemical composition in the greenhouse and field experiment (if counted well 110 samples were taken in total).
In most cases, the correlation between salinity and the remote sensing techniques indices was low. Please explain why coefficient of determination R2 on two different level 0.29 (line 389) and 0.63 (line 397) are ientical (moderate correlation).
Discussion
In my opinion, it requires a deep correction. It is too extensive and too many repetitions of the results section, or it relates to results not included in this chapter.
Author Response
Responses are on the attached file. Thanks for your inputs.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Authors answered and accepted most of the comments. I recommend manuscript for publication in Agronomy journal.
