Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2026, V. 23, No. 5, pp. 324-337
Mapping bare soils in Minsk Region using Sentinel-2 spectral indices
1 Belarusian State University, Minsk, Belarus
Accepted: 30.07.2026
DOI: 10.21046/2070-7401-2026-23-5-324-337
Bare soil is an important target in agricultural remote sensing, but its identification is complicated by spectral similarity to dry vegetation, crop residues, and bright anthropogenic surfaces. For Belarus, Sentinel-2-based approaches to bare-soil mapping remain insufficiently studied. This study aims to develop and test a threshold-based method for mapping open soil surfaces in Minsk Region using the Bare Soil Index (BSI), Normalized Difference Vegetation Index (NDVI), and Normalized Difference Built-up Index (NDBI). Sentinel-2 Level-2A imagery for 2024 was processed in Google Earth Engine (GEE) with clouds, shadows, snow, and invalid observations masked using the Scene Classification Layer (SCL); 27 threshold combinations were evaluated. The operational rule was defined as BSI > 0.18, NDVI < 0.20, and NDBI < 0.20. Validation using 1000 control points per quarter for Q2–Q4 yielded overall accuracies of 88.8–89.6 %, F1-scores of 87.7–88.6 %, and kappa values of 0.775–0.792. Random Forest models RF_index (using only BSI, NDVI, and NDBI) and RF_full (using Sentinel-2 spectral bands and indices) increased overall accuracy to 90.4–92.0 and 91.9–93.2 %, respectively. Most detected open surfaces were associated with arable-suitable land, but their within-class share did not exceed 1.0–1.6 %. The proposed approach is suitable for regional mapping of seasonally exposed soil surfaces provided that thresholds are locally calibrated, seasonal robustness is checked and accuracy is evaluated using control points.
Keywords: Sentinel-2; bare soil; remote sensing; Bare Soil Index; NDVI; NDBI; threshold classification; Random Forest; agricultural landscapes; Minsk Region
Full textReferences:
- Antonov S. A., Skripchinsky A. V., Avdeev A. V., Application of the Earth remote sounding data to verify the activities of agricultural producers, Sel’skokhozyaistvennyi zhurnal, 2018, No. 4 (11), pp. 6–11 (in Russian), DOI: 10.25930/9ywv-3r76.
- Genin V. A., Klebanovich N. V., Modeling maize and soybean yield using Earth remote sensing data, Vestnik of the Belarusian State Agricultural Academy, 2018, No. 4, pp. 100–104 (in Russian).
- Zemel’no-informatsionnaya sistema Respubliki Belarus’. Poryadok sozdaniya, vedeniya (ehkspluatatsii i obnovleniya): TKP 610-2023 (33520) (Land information system of the Republic of Belarus: Procedure for creation and maintenance (operation and updating): TKP 610-2023 (33520)), Minsk: State Committee on Property of the Republic of Belarus, 2023, 107 p. (in Russian).
- Kravtsov S. L., Privalov F. I., Golubtsov D. V., Lepesevich E. V., Kholodinsky V. V., Bulavina T. M., Lapanik S. A., Gvozdov A. P., Possibilities of remote monitoring use in agriculture of Belarus, Arable Farming and Plant Breeding in Belarus, 2017, Iss. 53, pp. 4–12 (in Russian).
- Chervan A. N., Geoinformatsionnaya formalizatsiya i geostatisticheskii analiz pochvennogo pokrova Belarusi: uchebno-metodicheskoe posobie (Geoinformation formalization and geostatistical analysis of the soil cover of Belarus: A study guide), 2025, Minsk, Belarusian State University, 175 p. (in Russian).
- Chervan A. N., Zhao B., Determination of soil organic matter content in Minsk Region of Belarus using gradient boosting classifiers based on satellite data, Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2025, V. 22, No. 3, pp. 121–135 (in Russian), DOI: 10.21046/2070-7401-2025-22-3-121-135.
- Ben-Dor E., Chabrillat S., Demattê J. A.M. et al., Using Imaging Spectroscopy to study soil properties, Remote Sensing of Environment, 2009, V. 113, pp. S38–S55, DOI: 10.1016/j.rse.2008.09.019.
- Breiman L., Random Forests, Machine Learning, 2001, V. 45, No. 1, pp. 5–32, DOI: 10.1023/A:1010933404324.
- Castaldi F., Sentinel-2 and Landsat-8 multi-temporal series to estimate topsoil properties on croplands, Remote Sensing, 2021, V. 13, No. 17, Article 3345, DOI: 10.3390/rs13173345.
- Congalton R. G., Green K., Assessing the accuracy of remotely sensed data: Principles and practices, 3rd ed., Boca Raton, CRC Press, 2019, 346 p., DOI: 10.1201/9780429052729.
- Demattê J. A.M., Fongaro C. T., Rizzo R., Safanelli J. L., Geospatial Soil Sensing System (GEOS3): A powerful data mining procedure to retrieve soil spectral reflectance from satellite images, Remote Sensing of Environment, 2018, V. 212, pp. 161–175, DOI: 10.1016/j.rse.2018.04.047.
- Deng Y., Wu C., Li M., Chen R., RNDSI: A ratio normalized difference soil index for remote sensing of urban/suburban environments, Intern. J. Applied Earth Observation and Geoinformation, 2015, V. 39, pp. 40–48, DOI: 10.1016/j.jag.2015.02.010.
- Drusch M., Del Bello U., Carlier S. et al., Sentinel-2: ESA’s optical high-resolution mission for GMES operational services, Remote Sensing of Environment, 2012, V. 120, pp. 25–36, DOI: 10.1016/j.rse.2011.11.026.
- Dvorakova K., Heiden U., Pepers K. et al., Improving soil organic carbon predictions from a Sentinel-2 soil composite by assessing surface conditions and uncertainties, Geoderma, 2023, V. 429, Article 116128, DOI: 10.1016/j.geoderma.2022.116128.
- Gorelick N., Hancher M., Dixon M. et al., Google Earth Engine: Planetary-scale geospatial analysis for everyone, Remote Sensing of Environment, 2017, V. 202, pp. 18–27, DOI: 10.1016/j.rse.2017.06.031.
- Griffiths P., Nendel C., Hostert P., Intra-annual reflectance composites from Sentinel-2 and Landsat for national-scale crop and land cover mapping, Remote Sensing of Environment, 2019, V. 220, pp. 135–151, DOI: 10.1016/j.rse.2018.10.031.
- Liu Y., Meng Q., Zhang L., Wu C., NDBSI: A normalized difference bare soil index for remote sensing to improve bare soil mapping accuracy in urban and rural areas, CATENA, 2022, V. 214, Article 106265, DOI: 10.1016/j.catena.2022.106265.
- Qi L., Zhou Y., Van Oost K. et al., High-resolution soil erosion mapping in croplands via Sentinel-2 bare soil imaging and a two-step classification approach, Geoderma, 2024, V. 446, Article 116905, DOI: 10.1016/j.geoderma.2024.116905.
- Qiu B., Zhang K., Tang Z. et al., Developing Soil Indices based on brightness, darkness, and greenness to improve land surface mapping accuracy, GIScience and Remote Sensing, 2017, V. 54, No. 5, pp. 759–777, DOI: 10.1080/15481603.2017.1328758.
- Rikimaru A., Roy P. S., Miyatake S., Tropical forest cover density mapping, Tropical Ecology, 2002, V. 43, No. 1, pp. 39–47.
- Rouse J. W., Jr., Haas R. H., Schell J. A., Deering D. W., Monitoring vegetation systems in the great plains with ERTS, 3 rd Earth Resources Technology Satellite-1 (ERTS-1) Symp., NASA SP-351, 1974, V. 1, pp. 309–317.
- Urbina-Salazar D., Vaudour E., Richer-de-Forges A. C. et al., Sentinel-2 and Sentinel-1 bare soil temporal mosaics of 6-year periods for soil organic carbon content mapping in Central France, Remote Sensing, 2023, V. 15, No. 9, Article 2410, DOI: 10.3390/rs15092410.
- Vaudour E., Gomez C., Lagacherie P. et al., Temporal mosaicking approaches of Sentinel-2 images for extending topsoil organic carbon content mapping in croplands, Intern. J. Applied Earth Observation and Geoinformation, 2021, V. 96, Article 102277, DOI: 10.1016/j.jag.2020.102277.
- Zepp S., Heiden U., Bachmann M. et al., Optimized bare soil compositing for soil organic carbon prediction of topsoil croplands in Bavaria using Landsat, ISPRS J. Photogrammetry and Remote Sensing, 2023, V. 202, pp. 287–302, DOI: 10.1016/j.isprsjprs.2023.06.003.
- Zha Y., Gao J., Ni S., Use of normalized difference built-up index in automatically mapping urban areas from TM imagery, Intern. J. Remote Sensing, 2003, V. 24, No. 3, pp. 583–594, DOI: 10.1080/01431160304987.
- Zhu Y., Qi L., Wu Z., Shi P., Spectra-based predictive mapping of soil organic carbon in croplands: Single-date versus multitemporal bare soil compositing approaches, Geoderma, 2024, V. 449, Article 116987, DOI: 10.1016/j.geoderma.2024.116987.