To the issue of the erosion component of calculating the balance of humus

The purpose of the article is to present the results of identifying the influence of water and wind erosion on the annual loss of humus from arable soils of Ukraine in the zones of Polissia, Forest-Steppe and Steppe at the regional territorial level, which negatively affect its balance. It is known that the irreversible annual soil loss under the influence of water erosion on average in the Polissia zone is 7.6, in the Forest-Steppe zone – 7.8, in the Steppe zone – 3.3 t / ha. It is shown that the erosion component in the part of humus losses approaches 40 %, strengthening the negative part of the balance. To obtain the most correct information on the humus balance in soils, a differentiated approach to balance models is recommended. At the regional territorial level, to calculate the predicted losses of humus because of erosion, the value of the average slopes on the arable lands of the administrative region, the average values of soil washout at specific slopes and soil and climatic conditions were used. It is proved that the calculation of the humus balance under individual agricultural crops, or in the crop rotation should include the average, in the administrative region, humus losses caused by water erosion, which differ significantly by regions in the soil and climatic zones of Ukraine (from 154 to 1700 kg/ha). According to the total losses of humus from water erosion, 3 groups of territories were identified: I – from 50 to 100 (South Steppe), II – from 140 to 200 (Polissia, Left-Bank Forest-Steppe and Northern Steppe), III – from 200 to 300 kg/ha (Right-Bank Forest-Steppe). In areas where there is a threat of deflation, the loss of humus caused by wind erosion, which in the southern part of the country ranges from 293 to 1700 kg/ha, significantly affects the humus state of the soil and should be included in the calculations of the humus balance along with the data on water erosion.