To the issue of the role of relief in the formation of spatial heterogeneity of soil parameters

Abstract

The results of the study of the role of relief in the formation of the spatial heterogeneity of humus content, avalable compounds of phosphorus and potassium, the total content of nitrogen and pHH2O within the arable layer are highlighted. The study was carried out on two fields in the Kharkiv region in the zone of the Left-Bank Forest-Steppe of Ukraine. The soil cover of one of the fields is represented by gray forest (Haplic Luvisol) and dark gray podzolized (Luvic Greyzemic Phaeozem) soils, the second – by podzolized chernozem (Chernic Phaeozem) (including reclaimed) and dark gray podzolized (Luvic Gremizem) with eroded counterparts. According to the granulometric composition, all soils are heavy loamy. Relationships were found between the main indicators of soil fertility and the characteristics of the relief of the surveyed land plots, cartographic materials were created for the spatial distribution of nutrients using statistical methods of data processing. The existence of spatial heterogeneity of soil properties (Cv > 25 %) was confirmed and factors influencing the features of their spatial distribution were determined. It was found that the existence of heterogeneous landforms and, in particular, the presence of microdepressions in the surveyed areas, causes an uneven distribution of precipitation, which significantly affects the formation of heterogeneity of soil quality within the field – the content of nutrients (nitrogen, phosphorus and potassium) and soil pH. The results show that the soil at high relief points and in micro-depressions is better provided with humus and available phosphorus compounds. The zones of available potassium and nitrogen enrichment coincide with depressions in the relief. The reason for the distribution of nutrients is the migration of flows of substances, the intensity of which depends on the topographic features of the territory. It was found that the soil at higher parts of the field is characterized by pHH2O values close to neutral. Relative acidification of the soil was found in areas with a sharp slope of the surface. Based on the results, recommended to take into account the peculiarities of the spatial distribution of soil properties in the practice of applying fertilizers and chemical ameliorants.