# Mapping of Kill Erosion of the Middle Volga (Russia) Region Using Deep Neural Network
## 4 Results and Discussion
Stabilization of the trend, in this case, is explained by the fact that 270 mm is a kind of boundary between steppe and forest-steppe zones, in which there is a clear seasonality of precipitation. By the time of the most intensive precipitation (summer-autumn period), vegetation with good soil-protective properties develops on these territories [24], which becomes the dominant factor of soil erosion intensification. The influence of moisture factors most clearly shows the relationship between the density of rill erosion and the value of the hydrothermal coefficient of the territory (Figure 15B). The density of the erosion network decreases with increasing GTK up to the value of 0.7--a clear border between arid area and wetted area. The intensity of soil-protecting vegetation increases with the increase of the SCC, but the precipitation becomes sufficient for the vegetation to perform its soil-protecting functions less effectively when moving into the wetted zone. The analysis of the influence of the geographical location of the basin on the intensity of erosion processes also demonstrated statistically significant relationships. The density of rill erosion decreases linearly as one move to the east of the study area (Figure 16A), which is explained by the fact that the western part of the study area has a higher right bank of the Volga River and, as a result, higher values of slope steepness, which, as shown earlier, directly affect the intensity of the process. The latitudinal pattern is not so linear and more complex (Figure 16B)--with moving from the south to the north up to the zone of typical steppes, there is a systematic increase in the density of rill erosion, after which there is some decrease in the intensity of soil erosion and its stabilization, after which, starting from the northern part of the forest-steppe zone there is another gradual increase in the intensity of erosion activity. The reasons for this, as previously shown, lie in the zonal features of the study area, changes in the degree of moisture, as well as the types of plant communities, including agricultural ones, growing in a particular area. It is worth separately considering the influence of soil-geological conditions of erosion processes. A one-factor analysis of variance was conducted to analyze the relationship between the prevailing soil type and total rill erosion length (Figure 17). The basic soils of taiga and coniferous-broadleaved forests, as well as hydromorphic soils, are least susceptible to erosion activity. The smallest total length of rills is observed on sod-podzol soils (shallow-podzol and deep-podzol). These taiga soils, as a rule, are covered by mixed forests with a dense canopy and good protection against the formation of surface runoff. Moving southward, there is a slight increase in the total length of the rill network on gray forest soils of various subtypes. These soils are actively involved in agricultural management and have suitable hydrometeorological conditions. Weak susceptibility to erosion of territories with hydromorphic soils is, in our opinion, evident and connected, by and large, with land use on such soils--these are meadows with maximum soil-protective properties. The next group of soils is more affected by erosion processes--steppe soils. These are all kinds of chernozems, starting from leached chernozems. Southern chernozems, which are peculiar \"record-breakers\" by erosion susceptibility among typical steppes soils, are distinguished. Southern chernozems are in the cluster with the highest density of erosion network (Figure 7). Southern chernozems are spread in the southern part of the steppe zone. They are formed in the conditions of semiarid climate under soddy-cereal medium steppes. Grass cover is sparse, clearly expressed summer semi-rest period for most dominant cereals. Soil-forming rocks are represented mainly by loess and loess-like loams, often containing easily soluble salts, as well as eluvial-deluvial deposits. Water conditions of soils are solid.