An assessment of the spatio-temporal variability of the humus content in the soil is presented, and atendency of its decreasing in the agro-climatic regions of the Luhansk region is established. The cartogramsof the humus content spatial distribution and the tendencies of changing its content in the soils of theLuhansk region for 20 years have been obtained. A very high humus content in the soil (from 4 to 6.5 %) isobserved in the northern, central, and, partially, in the southern and eastern parts of the first agroclimaticregion, where mainly thick and ordinary medium-humus chornozems are located in the loess rocks. In therest of the territory, the humus content varies mainly from 2 to 4 %. In most of the territory of the secondagroclimatic region, except for the southern strip, which stretches from the northwest to the southeast, thehumus content in the soil is 3–4%, interspersed with those areas with high (up to 4–6 %) humus content.The soil covers of the third agroclimatic region are characterized by a great variety of soil types. In most ofthe region, there are ordinary crushed chernozems on the eluvium of the dense bedrocks with a predominanthumus content of 2.5–4 %, and here, in a narrow strip (along the Anthracite – Sverdlovske line), there arepowerful medium-humus chernozems on the loess rocks with a high content humus up to 4–6 %, a small partof them is also in the south of the region. In the eastern part of the district (to the east of the Lutugino –Krasnodon line), there are ordinary medium-thick medium-humus chernozems and ordinary low-power lowhumuschernozems, where the humus content is mainly 2–3.5 %. Over the years of surveys between 1987–1991 and 2007–2011 against the background of sufficiently high humus content in the soil compared to theother regions of the Steppe zone of Ukraine, the decrease in the humus content in the first agroclimaticregion was 0.49 % in absolute terms (89.62 % of the results of the first survey), in the second agroclimaticregion – 0.29 % (92.45 % in relative values), in the third agroclimatic region – 0.1 % (97.48 % in relativevalues). The variation in the humus content in the soil is the smallest in the first agroclimatic region (thecoefficient of variation is 15.37 %), where the soil cover is more uniform, it is somewhat larger in the secondand third regions (the coefficient of variation is 20.0 and 20.67 %), where the soil cover is more variegated.The number of fields (cases) with a high humus content decreased, and the number with an average content,on the contrary, increased.
