Digital mapping of soil organic carbon stocks in Ukraine

Received 02.07.2019 Received in revised form 22.07.2019 Accepted 19.08.2019 Available online 01.09.2019 Aim. Create a digital map of organic carbon stocks in the soils of Ukraine using digital soil mapping technologies. Methods. To create a digital map, spatial prediction methods were applied using R programming language. Results. Based on information on the organic carbon content in soil of Ukraine, legacy soil maps, remote sensing materials and additional topographic and climatic characteristics using the digital mapping technology, a national digital map of soil organic carbon stocks in a 030 cm layer with a resolution of 1x1 km was created. Modelling of the spatial distribution of organic carbon stocks in mineral soils was performed using the Random Forest algorithm, in peat lands – using the kriging method. The most significant predictors for spatial distribution of soil organic carbon stocks in the country's soil cover were soil type, climate variables, spectral reflectance of bare soil in the near infrared range of the spectrum. Conclusions. The digital map of organic carbon stocks in Ukraine’s soils was developed in accordance with the specifications of the Global Soil Partnership of the United Nation Food and Agriculture Organization (FAO) and integrated into the FAO Global Soil Organic Carbon Map (GSOCmap). The created national digital map of carbon stocks in the soils of Ukraine can be used as a basis for further monitoring of organic carbon stocks, however, this task can be achieved only if a unified national soil information system is created, in which information on field surveys is accumulated and updated.