Mapping and Characterization of Planosols in the Omo-Gibe Basin, Southwestern Ethiopia

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. Can the authors clarify why the FAO soil map failed to recognize Planosols was it solely due to scale, or were there methodological limitations in prior classifications?
2. Why is the Random Forest (RF) model chosen over other machine learning models (e.g., SVM, XGBoost) for soil mapping, and how does its performance compare quantitatively in this context?
3. Could the authors provide a clearer explanation or justification for using the specific 30 m spatial resolution in mappinghow does this resolution affect accuracy or usability?
4. In Section 2.3, why were specific depths (0–10, 10–40, etc.) selected for soil sampling, and how do they correspond to the diagnostic horizons used in WRB classification?
5. There is a repeated phrase in lines 92–93: “characterization, classification, characterization”was this a typographical error, and should it be corrected to avoid redundancy?
6. What criteria or thresholds were used to determine when a soil profile would be classified as a Planosol, particularly in field validationcan the authors provide clearer classification rules?
7. The error matrix (Table 1) shows substantial misclassification between Planosols and Vertisols; what field indicators could improve separation between these two classes?
8. In the chemical analysis, what methods were used to control for possible contamination or variability in sample collection and lab handling that could affect pH or nutrient results?
9. Considering the low copper and boron levels found across profiles, were any plant response trials conducted to validate the recommendation of micronutrient fertilization?
10. Why is liming discouraged on these soils despite some surface layers being moderately acidic—can the authors explain the interaction between Ca:Mg ratios and nutrient uptake constraints?
11. How do the morphological and textural data support the hypothesis of a geogenetic versus pedogenetic origin of the abrupt E/Bt horizon boundary—could more supporting evidence be provided?
12. The recommendation to use broad bed-and-furrow (BBF) systems is made—was this tested in the study area, or is it extrapolated from similar agroecological zones?
13. How do the findings compare quantitatively (e.g., clay %, bulk density, CEC) with previous studies on Planosols in other African regionsare there notable deviations?
14. Could the authors improve the clarity and consistency in technical terminology (e.g., use of “Ap/Eg” vs “A/E”) to align with WRB standards?
15. Some sections (e.g., Figure captions, profile descriptions) are very detailed but may be too dense for general readers—could they be supported by summarized tables or graphical visualizations for easier interpretation?
16. In Table 4, H2O is not in proper format. Use the subscript. Also check this type of mistakes in whole paper.
17. There are many mistakes in references format. Please cite all reference in same references style which should be according to the journal format. Also add most recent literature such asdoi: 10.1080/24749508.2024.2429207, org/10.1016/j.gloplacha.2024.104602, doi.org/10.1016/j.catena.2024.108134. 

 

Author Response

Spatial Extent, Morphological Features, and Agronomic Constraints of Planosols in the Omo-Gibe Basin, South-western Ethiopian Highlands

 

Rebuttal to reviewers’ comments

Reviewer 1

We sincerely thank the reviewer for the time and effort dedicated to evaluating our manuscript. Your constructive comments and suggestions have been highly valuable in improving the clarity and quality of our work.

Comment #1: Can the authors clarify why the FAO soil map failed to recognize Planosols was it solely due to scale, or were there methodological limitations in prior classifications?

Response: Scale (1:2,000,000) is the most important cause for the misclassification of Planosol landscapes as Vertisols or Andosols. Given the huge diversities in agro-ecology, geology, climate, land use etc in the Ethiopian highlands, the exploratory (1cm on map =20 km on the ground) cannot capture diversities; at this scale only very, generalized information can be shown. The second problem is the use of satellite images and aerial photographs without adequate field validation through profile or auger observation supplemented by analytical data. Such field survey data was limited at the time.  

Comment#2: Why is the Random Forest (RF) model chosen over other machine learning models (e.g., SVM, XGBoost) for soil mapping, and how does its performance compare quantitatively in this context?

Response: Random Forest (RF) model is a widely applied machine learning algorithm in digital soil mapping and the scientific literature on this model is listed in the manuscript lines 152-153. In general, digital soil mapping research (see Heung et al 2016; Hengl etal, 2017; Breiman, 2001; Hengl et al, 2021) suggest that RF has strong accuracy with messy geospatial predictors specially when dealing with non-linear relationships, interactions, and correlated covariates. As our study sites are diverse topographic features (i.e., DEM), geology, climate, land use etc), we chose to use the RF model most suitable for our purpose from among other machine learning models.

Comment#3 – Could the authors provide a clearer explanation or justification for using the specific 30 m spatial resolution in mapping how does this resolution affect accuracy or usability?

Response: Yes, we used the 30m resolution (i.e., a uniform 30m x 30m area on the ground for soil mapping in ArcGIS v10.5 environment. This is the highest spatial resolution best available to us because national-scale covariates line up is at 30 m obtained from the Ethiopian Geospatial and Space Science and Geospatial Institute. Using environmental covariates at their original resolution avoids resampling and preserves signal in terrain derivatives (slope, curvatures, cover, etc). In addition, recent continental study demonstrates that 30m resolution is reproduceable for digital soil class and property mapping providing an acceptable accuracy with balance of detail and noise (see Hengl et al, 2021).

Comment #4. In Section 2.3, why were specific depths (0–10, 10–40, etc.) selected for soil sampling, and how do they correspond to the diagnostic horizons used in WRB classification?

Response: We chose the sampling depths of 0-10, 10-40, 40-80, and 80-120 cm to align with morphological characteristics of Planosols and the observed pedogenic horizons observed in the sample profiles. In our profile observations, the Ap horizon (the cultivated surface layer) of these Planosols is sandy and thin, not exceeding 10 cm. Sampling 0-10 cm allowed us to capture this ploughed surface horizon without mixing it with the material below. Beneath the Ap horizon is a bleached, silty layer (E horizon), which goes down to about 40 cm. This layer is separated from the illuvial clayey horizon below by a distinct change in texture. This difference is a key feature of Planosols under the WRB (IUSS WRB, 2022). The 10-40 cm interval was designed to describe this eluvial horizon in detail. The 40-80 cm and 80-120 cm intervals focus on the Bt horizon (argic horizon) and deeper subsoil material, which helps us capture the complete vertical variation in texture, structure, and chemical properties needed for classification and interpretation. These deeper layers are important for identifying the abrupt textural difference and confirming the presence of the argic horizon, both of which are essential for diagnosing Planosols in the WRB.

Comment #5. There is a repeated phrase in lines 92–93: “characterization, classification, characterization” was this a typographical error, and should it be corrected to avoid redundancy?

Response: Thank you very much for pointing out to this mistake. It is typo error and now corrected in the manuscript as “characterisation and classification”

Comment #6 : What criteria or thresholds were used to determine when a soil profile would be classified as a Planosol, particularly in field validation can the authors provide clearer classification rules?

Response: We strictly followed the WRB (2022) diagnostic criteria for the classification of a soil profile as a Planosol. These include combination of a bleached, coarse-textured eluvial horizon overlaying a finer-textured, dense, and periodically saturated subsoil. Abrupt textural differentiation occurs when a coarse-textured surface or subsurface horizon (sandy, loamy sand, or silt loam) suddenly overlays a denser, finer-textured subsoil (clay loam to heavy clay). In our field-validated profiles, the percentage of clay increased by more than 40% on average when moving from the Eg horizon to the underlying Bss or Bt horizon, far exceeding the WRB minimum thresholds for defining an abrupt textural change.

Comment#7: The error matrix (Table 1) shows substantial misclassification between Planosols and Vertisols; what field indicators could improve separation between these two classes?

Response: The confusion matrix is correct (Table 1). This is because of the fact that both soil types can be dark and seasonally waterlogged, and Planosls show vertic features in the subsoil. In addition, the landscape position of occurrence often overlaps – plains, foothills with seasonal waterlogging. In field validation, we use the abrupt textural differentiation with a thin, coarse Ap over a bleached Eg (grey, eluviated) to ~40 cm, then a dense, finer Bt/Bss horizon as major diagnostic criteria differentiate Planosols from Vertisols. Clear E horizon is key. Unlike Planosols, Vertisols exhibit no bleached E horizon; the profile is uniformly very clayey from near the surface downward.

Comment#8. In the chemical analysis, what methods were used to control for possible contamination or variability in sample collection and lab handling that could affect pH or nutrient results?

Response: Although the questions not very clear, we want to note that the soil survey was conducted by group soil scientists who have vast experiences in profile description, auger observation, sample collection etc. We followed standard sample handling procedures during sample collection, bagging, labelling and delivering to the soil fertility laboratory properly.  The Soil Fertility Laboratory of the Water Works Construction and Design Enterprise of the Ministry of Water in Ethiopia, conducted the chemical analyses. This well-established national reference laboratory with decades of experience in soil and water analysis. It is fully equipped with modern and calibrated analytical equipment to determine pH and nutrient results. The lab follows standardized protocols that are aligned with the FAO and ISO guidelines. Laboratory staff are highly trained and regularly participate in quality assurance programs, including proficiency testing with international reference labs. The lab enforces strict sample handling procedures, uses certified reagents, and calibrates instruments before each batch of analysis. These capabilities ensure accurate, repeatable, and reliable pH and nutrient results that are not affected by poor handling and contamination.

Comment# 9.  Considering the low copper and boron levels found across profiles, were any plant response trials conducted to validate the recommendation of micronutrient fertilization?

Response: Although no new crop response trials were conducted in this study, relevant evidence comes from the Ethiopian Soil Information System (EthioSIS) program (Karltun et al, 2013). This program was implemented by the Agricultural Transformation Agency (ATA) and the Ministry of Agriculture (MoA) from 2011 to 2013. It carried out extensive on-farm field trials and demonstration plots across Ethiopia comparing different combinations of micro-and macro nutrients. Some of these sites were within our study area. The goal was to assess crop responses to macro- and micronutrient applications and formulated appropriate fertilizer blends including NPK, Zinc, boron but only rarely copper. The results showed measurable yield benefits in soils that lacked nutrients some micro-nutrients (Zn abd B) and Cu in some pocket areas. Based on these findings, regional and local level fertilizer recommendations were updated for the study area 13.7% N, 27.4% P₂O₅, 14.4% K₂O, 5.1% S, and 0.54% B. Boron was specifically targeted to address the identified deficiencies. Our recommendations for micronutrient fertilization are therefore consistent with these nationally validated plant response trials. Although EthioSIS project supported by ATA and MoA have demonstrated the agronomic benefits of NPK-B blend, there is a need for implementing targeted crop response trials on PLanosols with fertilizer blends containing copper in light of the observed copper deficiency in these soils. See the manuscript for the necessary corrections/revisions made under the management recommendations section.

Comment# 10. Why is liming discouraged on these soils despite some surface layers being moderately acidic—can the authors explain the interaction between Ca:Mg ratios and nutrient uptake constraints?

Response: Thank you for this comment. Upon careful observation of data in Table 4, we note that the Ca/Mg ratios are relatively low, ranging from 3 to 4 across all profile horizons (Table 4), 3and therefore, there is no risk of nutrient imbalance in these soils. Liming can cause nutrient antagonism and depress uptake of other cations (e.g., K+, Mg 2+, Zn2+) only when the Ca: Mg ratios exceed the threshold level of 10. Therefore, the “do not lime” recommendation is omitted and liming recommendation is included (see revised manuscript).

Comment #11. How do the morphological and textural data support the hypothesis of a geogenetic versus pedogenetic origin of the abrupt E/Bt horizon boundary—could more supporting evidence be provided?

Response: This is beyond the scope of our study. The geogenetic versus pedogenetic ferrolysis origins of the abrupt textural change is brought in our paper as part of the literature review highlighting the fact that the topic is still remains a subject of debate and topic for further research. Commenting or confirming either of the theories require comprehensive mineralogical analysis which was not the orientation of our study; we focused on morphological characteristics and distribution of the soils rather than their pedogenetic formation. A full pledged research article has devoted to unpack the ferrolysis vs pedogenetic processes in the formation of Planosols in the Ethiopian highlands (see Van Ranst etal 2011). This article based on research findings conducted in our study area concludes that the formation of Ethiopian Vertic Planosols is more convincingly explained by geogenetic processes than by the traditionally assumed pedogenetic ferrolysis process. While ferrolysis, which is the cyclic reduction and oxidation of iron that causes clay breakdown, has often been regarded as the main reason for the sudden textural contrast in Planosols, field, mineralogical, and chemical evidence from the Gilgel Gibe catchment of the Omo-Gibe basin, our study area, suggests otherwise. The findings show relatively high pH, plenty of weatherable minerals like feldspars and volcanic glass, and a high phytolith content, all of which contradict active ferrolysis. Instead, the authors suggest a geogenetic sequence that starts with the formation of Vertisol followed by selective lateral erosion that concentrated Fe–Mn nodules, and subsequent deposition of volcanic ash over the Vertisol. Weathering of volcanic glass, biological cycling of silica through grasses (phytoliths), and limited mixing from biological activity led to the formation of the bleached, silty surface horizon that sharply sits on top of the clay-rich vertic subsoil. This process explains the duplex nature of the soil without needing to reference ferrolysis (Van Ranst et  al 2011).

Comment #12: The recommendation to use broad bed-and-furrow (BBF) systems is made—was this tested in the study area, or is it extrapolated from similar agroecological zones?

Response: The Joint Vertisol Management Project, implemented by the International Livestock Centre for Africa (now the International Livestock Research Institute, ILRI) in collaboration with the Ministry of Agriculture, has developed improved Vertisol management technologies, the most widely recommended being the broad bed and furrow (BBF) system. This technology has been extensively tested across various agroecological zones of the Ethiopian highlands and has proven particularly suitable for the vertic soils in our study area, where it enhances drainage and improves water management on vertic Planosl (Jabbar et al, 2001).

Comment #13:How do the findings compare quantitatively (e.g., clay %, bulk density, CEC) with previous studies on Planosols in other African regions are there notable deviations?

Response: Thank you and we have addressed the question as below and included it in the discussion section of the revised manuscript.

Although there is limited published information and data on Planosols for quantitative comparison, we gathered available data on clay content, bulk density, pH, and CEC from various sources to compare our findings. Data on Planosols from previous work in the Ethiopian highlands were obtained from Van Ranst et al. (2011). For Kenya, we extracted values from two profiles in the ISRIC Africa Soil Profile Database (Leenaars et al., 2013). East Africa regional averages were ap-proximated from the WRB lecture notes on the major soils of the world (Driessen & Dudal, 2001) and the ISRIC Africa Soil Profile Database. The quantitative means for Ethiopia, Kenya, and East Africa are summarized in Table 6. The data shows that across the sub-region, surface (Ap/Eg) horizons of Ethiopian and Kenyan Planosols tend to have moderately low clay contents (20–29%), acidic pH (5.2–5.8), and with relatively low CEC values (11–26 cmol/kg), which are closely aligned with East Africa regional averages. In contrast, subsurface (Bs/Bt) horizons in all datasets exhibit a pronounced clay increase (37–74%), higher bulk density (1.7–1.8 g/cm³ in Kenya vs. ~1.3 g/cm³ in Ethiopia), higher pH (up to 6.5), and substantially higher CEC (37–47 cmol/kg). These values are fully consistent with WRB reference ranges for Planosols —indicating no notable deviation of our data from regional precedents.

The close agreement between our Ethiopian dataset and the available East Africa averages reinforces the reliability and regional representativeness of our results, which not only validates our field and laboratory measurements but also situates our findings within the broader pedological context of the region. By providing systematically collected and well-documented data on Planosol morphological and chemical properties, our study fills an important knowledge gap in eastern Africa, where published quantitative information on this Reference Soil Group remains scarce.The addition of these new data points improves the existing regional soil information, enhancing future comparative studies, digital soil mapping efforts, and agro-ecological assessments. This strengthens the empirical foundation for both soil classification and targeted land management suggestions in regions where Planosols occur under similar agro-climatic and land-use conditions.

Table 6. Quantitative comparison of mean values of selected properties of Planosol profiles for Ethiopia, Kenya and Eastern Africa region

Property	Horizon	Ethiopia (Current study	Ethiopia (previous)	Kenya (mean)	East Africa (mean)
Clay (%)	Ap	29	27	20	23
	Eg	28	23	28	27
	Bs/Bt	60	63	70	74
Bulk density (g/cm3)	Ap	1.1	NA	1.3	1.4
	Eg	1.2	NA	1.5	1.6
	Bs/Bt	1.29	NA	1.8	1.7
pH (H2O)	Ap	5.6	5.2	5.4	5.5
	Eg	5.8	5.3	5.8	5.7
	Bs/Bt	6.2	5.9	5.9	6.5
CEC (Cmol/kg)	Ap	26	21	21	18
	Eg	20	16	11	13
	Bs/Bt	41	46	47	37

 

Comment #14: Could the authors improve the clarity and consistency in technical terminology (e.g., use of “Ap/Eg” vs “A/E”) to align with WRB standards?

Response: To be consistent, we adopted Ap/Ep rather than A/E in the revised text. The following is provided what the upper case and subordinate letters denote in the soil profile description.  According to standard soil profile description, the master horizons in a soil profile are denoted by the letters O, A, E, B, and C (see FAO, 2006). In our sample horizons, the organic horizon (O) is largely absent due to degradation and depletion of organic matter. The profile typically begins with the A horizon, a mineral layer that has been altered by human activities such as cultivation, grazing, or clay mining. The E horizon is a bleached mineral layer characterized by the loss of silicate clay, iron, aluminium, or a combination of these, resulting in a concentration of sand particles. While the E horizon is absent in most soil types, its presence as a distinct bleached layer is a defining feature of Planosols. The B horizon is a subsurface layer marked by clay illuviation (accumulation), as well as the enrichment of cations and, in some cases, carbonates. Subordinate characteristics, indicated by lowercase letters such as “p,” “g,” and “ss,” describe special features observed within the master horizons and are assigned during field profile description in the field. For example, “p” denotes human disturbance, so Ap refers to a ploughed or otherwise disturbed surface layer. The letter “g” indicates gleying or water stagnation, hence Eg signifies an E horizon with stagnic conditions caused by an underlying dense clay layer that impedes water percolation. The symbol “ss” denotes slickensides—polished, grooved shear surfaces formed by the shrink–swell action of clay, a characteristic feature of Vertic soils.

Comment #15: Some sections (e.g., Figure captions, profile descriptions) are very detailed but may be too dense for general readers—could they be supported by summarized tables or graphical visualizations for easier interpretation?

Response: The objective of our study was to characterize the morphological and chemical properties of Planosols, after first exploring and mapping their distribution and highlighting their agricultural importance in the Ethiopian highlands. The nature of profile description necessitates presenting detailed morphological and chemical data for each horizon, following the standard profile data format widely used in soil science literature. Many of these horizon-by-horizon data are difficult to condense into a single figure without losing critical details essential for soil databases. If there are specific datasets you believe could be effectively summarized in a table and presented as a figure, we would be glad to consider your suggestion. In this case, however, we found no suitable alternative without compromising important information, and we appreciate your kind understanding.

Comment #16. In Table 4, H2O is not in proper format. Use the subscript. Also check this type of mistakes in whole paper.

Response: Thank you for picking this typo and correction is made in the text.

Comment #17: There are many mistakes in references format. Please cite all reference in same references style which should be according to the journal format. Also add most recent literature such as doi: 10.1080/24749508.2024.2429207, org/10.1016/j.gloplacha.2024.104602, doi.org/10.1016/j.catena.2024.108134.

Response: Thank you for pointing out the issues with reference formatting and the need to strengthen the manuscript with recent literature. We have thoroughly revised the reference list made the necessary corrections including (i) correcting formatting inconsistencies according to the journal’s guidelines (numbered style), (ii) removing uncited references, (iii) ensuring all cited works are listed, and (iv) adding DOI links wherever available. In addition, we incorporated several new and relevant recent references into the Introduction, Methods, and Discussion sections to strengthen the scientific context. More importantly, a number of new relevant references were added as per the revie in the introduction, methods and discussion sections.

Comment: Also add most recent literature such as doi: 10.1080/24749508.2024.2429207, org/10.1016/j.gloplacha.2024.104602, doi.org/10.1016/j.catena.2024.108134.

Response: With regard to the specific suggested articles:

The article doi: 10.1080/24749508.2024.2429207 and doi.org/10.1016/j.gloplacha.2024.104602 focus eson lateritization and ferruginous protore enrichment in the Mekaneselam iron deposit (NW Ethiopian Plateau). These works are geology-oriented, centered on ore genesis, and fall outside the scope of our study, which is focused on pedology and soil morphological characterization. Thus, it does not provide direct relevance for citation in our manuscript. Similarly, the article doi.org/10.1016/j.catena.2024.108134 examines permafrost thawing and geomorphological reshaping along the China-Russia crude oil pipeline. Given its thematic focus on cold-region geomorphology, it has limited applicability to the Ethiopian highland soils studied in our work.

Instead, we have reviewed and included in the revised manuscript most relevant and recent (i.e., post-2020) articles such as the ones listed below based on the reviewer’s comments:

Ali, A., et al., Reference soil groups map of Ethiopia based on legacy data and machine learning technique: EthioSoilGrids 1.0. SOIL 2024. 10: p. 189–20. https://doi.org/10.5194/egusphere-2022-301

Hengl, T., et al., African soil properties and nutrients mapped at 30 m spatial resolution using two-scale ensemble machine learning. Scientific reports, 2021. 11(1): p. 6130. | https://doi.org/10.1038/s41598-021-85639-y

IUSS Working Group, W., World Reference Base for Soil Resources: International Soil Classification System for naming soils and creating legends for soil maps 4th edition. 2022, International Union for Soil Science Vienna, Austria.

Shabtai, I., et al., Effects of land use on structure and hydraulic properties of Vertisols containing a sodic horizon in northern Ethiopia Soil and Tillage Research, 2014. 136.

Jabbar, M.A., T.M. Tekalign Mamo, and M.M. Saleem, From plot to watershed management: experience in farmer participatory Vertisol technology generation and adoption in highland Ethiopia, in The sustainable management of vertisols. 2001, CABI Wallingford UK. p. 173-186.

 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presents a comprehensive study on the distribution, morphological properties, and agronomic limitations of Planosols in the Omo-Gibe Basin, Ethiopia. The integration of field survey data, laboratory analysis, and digital soil mapping using Random Forest (RF) makes this a valuable contribution to both regional land management and global understanding of Planosols. The topic is timely and relevant to the journal’s scope. However, some aspects of the manuscript still have certain shortcomings.

1.While the study provides important baseline data on Planosols in Ethiopia, the novelty of the work is not sufficiently emphasized in the Introduction or Conclusion.

2.Some references are improperly formatted or incomplete. Ensure consistency with the journal’s citation style.

3.The manuscript refers inconsistently to FAO, WRB, and local classification systems. The authors should clarify which framework is used primarily and apply it consistently throughout the paper.

4.The conclusion section is too descriptive and repetitive. It should be revised to highlight the broader implications of the findings, potential for policy uptake, and directions for future research.

5.Figures 3-5 require more informative legends.

Author Response

Reviewer #2 – Rebuttal

We are very grateful to the reviewer for the insightful and constructive feedback. The thoughtful remarks and recommendations have significantly contributed to enhancing the rigor and presentation of our manuscript.

Comment #1: While the study provides important baseline data on Planosols in Ethiopia, the novelty of the work is not sufficiently emphasized in the introduction or Conclusion.

Response: We have added a brief text in the introduction section and a more extended text in the conclusion section the below text that emphasize the novelty of the work.

Text added in the introduction section - To this end, we quantitatively benchmarked key properties of Planosol profiles across Eastern Africa and identifying actionable management guidance—broad-bed-and-furrow drainage to alleviate seasonal waterlogging; NPKS blends with B and Cu to address nutrient constraints; and, where Ca: Mg ratios permit, targeted site-specific liming to amend topsil acidity—providing a transferable rehabilitation package for areas where mapping gaps and management debates persist.  Given the substantial regional extent of Planosols, implementing these evidence-based practices can yield meaningful and sustainable gains in ag-ricultural productivity across Eastern Africa.

Text added in the conclusion section – This study presents the first high-resolution (30 m) digital map of Planosol landscapes in Ethiopia’s Omo-Gibe basin that were previously misclassified as Vertisols and at times as Andosols in the national exploratory map at 1:2,000,000 scale. By integrating over 200 auger observations, 74 georeferenced profiles, and 296 laboratory analyses with Random Forest modelling, we achieved 89% classification accuracy (κ = 0.77) and identified that Planosols occupy approximately 18% (545,531 ha) of the basin in two distinct eco-regional belts. The morphological and chemical characterization confirmed that these soils exhibit the key features of Planosols described in the WRB, and align closely with profiles reported elsewhere across eastern Africa. The quantitative comparison of the morphological and chemical characteristics of the Planosol profiles in this study closely aligns with the criteria for Planosols outlined in the WRB and the information available for similar soils in eastern Africa, where Ethiopia is one of the key areas of Planosol occurrence. This reinforces that our findings and shows that the methods we applied and management insights provided can be transferred to similar agroecological settings in eastern Africa. Additionally, the results add to the current scientific debates about the classification and management of Planosols, a Reference Soil Group that is still under discussion and refinement within the World Reference Base system.

Comment #2: Some references are improperly formatted or incomplete. Ensure consistency with the journal’s citation style.

Response: Thank you very much for this helpful comment. WE have taken care of inconsistencies in the reference and applied the journal format. See the revised manuscript.

Comment #3: The manuscript refers inconsistently to FAO, WRB, and local classification systems. The authors should clarify which framework is used primarily and apply it consistently throughout the paper.

Response: As indicated in the Methods section (lines 128-129), the morphological characterization of soil profiles was conducted following the FAO Guidelines for Soil Description (FAO, 2006). Classification at the Reference Group level was carried out in accordance with the conventions and legend of the World Reference Base for Soil Resources (IUSS Working Group WRB, 2014). No indigenous or local soil classification systems were applied in this study.

Comment# 4: The conclusion section is too descriptive and repetitive. It should be revised to highlight the broader implications of the findings, potential for policy uptake, and directions for future research.

Response: We made significant revision in the conclusion section and addressed all issues pointed out in this comment (see the revised manuscript).

Comment #5: Figures 3-5 require more informative legends.

Response: Relevant corrections are made and necessary information is added in the captions of Figures 3-5. We see no need to change legend; properly worked out already.

 

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The work has been rightly submitted to a journal that stands out in the field of sustainability, this success is supported, above all, by the findings that allow generating new interpretations of land use, a condition that should impact the agricultural practice of the primary users of this resource, at the same time the work will support readers interested in fundamental agricultural practices and could influence the use of the land by local producers, it is important to recognize that this work resorts, with detailed precision, to soil analysis resources that allow access with equal detail to the data presented and discussed, for this reason I recommend its publication.

Comments on the Quality of English Language

The language is used in a correct manner and can be used by non-experts in the subject they deal with.

Author Response

Reviewer #3: 

We sincerely appreciate the reviewer’s careful evaluation of our manuscript and the helpful comments provided. Below, we address each point in detail and indicate the revisions made accordingly.

The work has been rightly submitted to a journal that stands out in the field of sustainability, this success is supported, above all, by the findings that allow generating new interpretations of land use, a condition that should impact the agricultural practice of the primary users of this resource, at the same time the work will support readers interested in fundamental agricultural practices and could influence the use of the land by local producers, it is important to recognize that this work resorts, with detailed precision, to soil analysis resources that allow access with equal detail to the data presented and discussed, for this reason I recommend its publication.

Response: We thank the reviewer for the encouraging and thoughtful feedback. We are glad the reviewer sees the importance of our findings for improving scientific understanding and guiding land-use decisions. It is gratifying to know that the detailed soil analyses and high-resolution mapping were viewed as valuable contributions. It is our sincere hope that the editor-in-chief will agree with this and accept the paper for publication.

Author Response File: Author Response.docx

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Authors, 

I have the privilege to review this manuscript throughly, and found some major issues that are needed your positive response to get this manuscript improved. 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

I do recommend enhancing the language writing style .

Author Response

Reviewer #4

We sincerely appreciate the reviewer’s careful evaluation of our manuscript and the helpful comments provided. Below, we address each point in detail and indicate the revisions made accordingly.

1. Language and Grammar Issues suggesting reflecting their restriction to pocket areas” → Redundant, revise as either “suggesting their restriction…” or “reflecting their restriction

Response: thank you and correction is done

Comment: The soils are composed of a weathered volcanic ash layer deposited on top of deflated vertic sub-soil → Should be simplified for clarity.

Response: This is a typical morphological expression for Planosols globally.

“Misplaced modifiers, e.g., “Abrupt textural change from the coarse-textured light grey Ap/Eg horizon… abruptly overlay a very clayey…” → Needs rephrasing.

Response: Thank you and we corrected the sentence as “Abrupt textural change occurs from the coarse-textured, light grey Ap/Eg horizon to a very clayey subsoil horizon”.

2. Title and abstract:

Title: “Mapping and Characterization of Planosols in the Omo-Gibe Basin, Southwestern Ethiopia”

Response: Accepted and correction is made.

Abstract: Lacks clarity and logical flow. It contains unnecessary details (e.g., horizon colors and Munsell codes). Instead, emphasize objectives, brief methods, key results, and practical implications.

Response: Thank you for this observation. We made extensive revision of the abstract section avoiding unnecessary details on soil morphology and focusing on objectives, brief methods and key findings of the study. See the revised manuscript.

3. Hypothesis and Objectives

Comment: The manuscript does not clearly state a hypothesis. Objectives are vague and should be rewritten clearly.

Response: Hypothesis and clear objectives are formulated in the revised manuscript. The newly added text is givenbelow:

The overall aim of the study is to test the hypothesis that higher spatial resolution mapping and detailed characterization of Planosols will reveal the extent of the soils and their distinctive pedological properties thereby avoiding their misclassification in soil surveys, and provide essential information and baseline knowledge needed for their sustainable management in agricultural landscapes in the Ethiopian highlands. The specific objectives were (a)  map the spatial extent and distribution patterns of Planosols in the Omo-Gibe Basin at reconnaissance scale (1:250,000), in order to improve classification accuracy compared to previous exploratory-scale (1:2,000,000) maps that often misidentified Planosols as Vertisols and sometimes as Andosols; (b) characterize the morphological, physical, and chemical properties of representative Planosol profiles to generate scientifically robust baseline data for classification and pedological interpretation, addressing the current paucity of information on these soils in Ethiopia and Eastern Africa; (and (c) assess the agronomic constraints and management implications of Planosol landscapes with a view to informing farmers, extension agents, and policymakers on sustainable agricultural utilization.

4. Literature Review

Comment: The review is not comprehensive and lacks recent studies (post-2020) on digital soil mapping and Planosols management.

Response: We appreciate the reviewer’s suggestion to include additional, recent (post-2020) references on digital soil mapping and Planosol management. While digital soil mapping (DSM) continues to gain broader attention, our literature search has revealed a notable scarcity of focused studies on Planosols thus, highlighting both a research gap and one of the key motivations for this study. Planosols, being inherently infertile on the surface and naturally marshy, are underutilized in agriculture and correspondingly underrepresented in soil science literature. This underscores their marginal status in both cultivation and academic attention. The following two references are post-2020 and they have been reviewed and strengthened our points of argument in the introduction and methods section regarding the use DSM using RF model:

Ali et al. (2024): “Reference soil groups map of Ethiopia based on legacy data and machine learning technique: EthioSoilGrids 1.0”. This study developed a 1:1,000,000 digital soil resource map of Ethiopia by harmonizing ~14,600 legacy soil profiles using Random Forest, but again because of its coarse scale and the historical misclassification of Planosols in the Legacy profile dataset, the map could not adequately capture the Planosols landscapes of the Ethiopian highlands. We have now reviewed and cited Ali et al. (2024) in the revised manuscript to acknowledge this important work while clarifying how our study complements and extends its findings.

Hengl et al., 2021 applies ensemble machine learning at a 30 m resolution across Africa significantly advancing DSM data quality and demonstrating the potential of these techniques. This refernce along with Leenaars et al. (2020) are foundational references for mapping soil-landscape resources across the Ethiopian Highlands using Random Forest.

5. Methodology

• Section is detailed but clarity and reproducibility need improvement. Summarize RF model steps and clarify sampling strategy.

Response: We thank the reviewer for this helpful comment. In the revised manuscript, we have summarized the Random Forest workflow into clear, stepwise procedures covering covariate selection, data integration, model training, validation, and map production. This improves reproducibility by showing exactly how the RF model was implemented. We also clarified the sampling strategy by explicitly describing the auger observation, profile description and morphological characterisation protocol and criteria for delineating soil boundaries, profile description protocol.

6. Results and Discussion

Comment: Some tables/figures are overloaded with raw data. Move details to supplementary material.

Response: We appreciate the suggestion. However, moving these items to the annex would omit information essential for interpreting soil–profile morphology and classification. The current presentation follows standard practice in soil science. The dense nature of profile description necessitates presenting detailed morphological and chemical data for each horizon, following the standard profile data format widely used in soil science literature. If specific figures or tables are preferred as supplementary materials, we are happy to relocate those upon request.

Comment: Strengthen discussion by comparing with similar studies.

Response: We appreciate this suggestion and have substantially revised the discussion section to situate our results within national, regional, and global literature. In addition, we benchmarked our soil–landscape associations and the morphological and chemical characteristics of the profiles examined (profile chemistry) against continental syntheses and harmonized African soil maps, showing good agreement in catenary positions. A number of new relevant literature have been reviewed and comparative analysis. See the revised manuscript.
7. Management Recommendations

Comment: Good insights but need stronger linkage with results and socio-economic feasibility

discussion.

Response: Yes, this has been addressed. We linked management recommendations (BBF drainage; balanced NPKS + B and Cu trials) to documented performance of drainage interventions and evolving national fertilizer guidance.

8. Conclusion

Comment: Well-written but could be more concise. Remove repetition and emphasize implications.

Response: Thank you for this recommendation. We have made significant revision in the conclusion section highlighting the novelty of the work and its broader implications.

9. References

Comment: References need proper formatting and recent updates. Fix broken DOIs.

Specific Errors

- Typographical: “landscapes was misclassified” → should be “landscapes were

misclassified”.

- Unit inconsistencies and figure-caption mismatches.

- Double words: “characterization, classification, characterization”.

- Incomplete references with broken links.

Response: Thank you for pointing out these weaknesses which we have carefully addressed including avoiding Brocken Dois, correcting typographic errors and adhering to the journal styles.

Specific errors: Kindly noted and necessary corrections are made in the revised manuscript.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for submitting the revised manuscript. However, the use of the 'Track Changes' feature has made the document difficult to navigate for review.

To facilitate the final evaluation, please provide a clean version of the revised manuscript alongside a separate, point-by-point response letter. In this letter, please restate each reviewer comment and detail your corresponding changes. Please ensure your responses are highlighted or in bold text to allow for easy verification.

I look forward to receiving the materials in this revised format. 

Comments on the Quality of English Language

The manuscript would benefit from careful editing for grammar and style

Author Response

Comment: Thank you for submitting the revised manuscript. However, the use of the 'Track Changes' feature has made the document difficult to navigate for review. 

To facilitate the final evaluation, please provide a clean version of the revised manuscript alongside a separate, point-by-point response letter. In this letter, please restate each reviewer comment and detail your corresponding changes. Please ensure your responses are highlighted or in bold text to allow for easy verification.

I look forward to receiving the materials in this revised format. 

Comments on the Quality of English Language: The manuscript would benefit from careful editing for grammar and style

Response: Thank you very much for your valuable comments that have helped us to strengthen the manuscript. We fully agree with your suggestion and have arranged for the language to be improved by professional native speakers. Both the clean version and the track-changed version of the manuscript have been prepared and uploaded separately in the system.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The author careful revision has significantly improved the manuscript's clarity, logic, rigor, and argumentation. The key concerns identified in the previous review have been satisfactorily resolved in the revised draft. Additions and revisions have effectively addressed the previous points of uncertainty. The final revised manuscript constitutes a high-quality, original paper offering an important contribution to the field.

Author Response

Comment: The author careful revision has significantly improved the manuscript's clarity, logic, rigor, and argumentation. The key concerns identified in the previous review have been satisfactorily resolved in the revised draft. Additions and revisions have effectively addressed the previous points of uncertainty. The final revised manuscript constitutes a high-quality, original paper offering an important contribution to the field.

Response: Thank you very much for your valuable comments that have helped us to strengthen the manuscript.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Authors,

I have reviewed your manuscript carefully, and I can see remarkable insertions have been made across the manuscript .

Comments on the Quality of English Language

The English writing style needs some corrections and modifications. 

 

Author Response

Comment: I have reviewed your manuscript carefully, and I can see remarkable insertions have been made across the manuscript . The English writing style needs some corrections and modifications. 

Response: Thank you very much for your valuable comments that have helped us to strengthen the manuscript.  We fully agree with your suggestion and have arranged for the language to be improved by professional native speakers from MDPI language  services.