SOIL DISTRIBUTION IN PCINJA RIVER BASIN, NORTH MACEDONIA AND ITS IMPORTANCE FOR AGRICULTURAL PRODUCTION

This paper is a result of many years of field and laboratory research of the soils in Pčinja river basin, North Macedonia, spread out on 237.640,71 ha ranging from 191 to 1664 m above the sea level in order to gain a better understanding of the productive capacities of the soils and measures for their improvement. The catchment area of Pčinja River is a spatial area that extends in two states in the of the Republic of North Macedonia and the part of the Republic of Serbia, whose boundaries are naturally clearly defined. Soil samples were taken by spade and one composite sample was prepared for each sampling site, each containing about 3 kg of soil. Before sieving the samples were air dried. In laboratory, the following analyses have been carried out on the soil samples: hygroscopic moisture, mechanical composition, pH of the soil solution, humus content and total nitrogen, content of carbonates. The mechanical composition and chemical properties of the soils have been determined by standard methods. This area is very heterogeneous, with numerous relief forms, with different expositions and inclinations, and with great differences of altitude. Additionally, there are several geological formations of a very heterogeneous petrographic-mineralogical composition and climate-vegetation zones. Long-term effects of human involvement should also be noted. The vast diversity of the factors required for soil formation in this area is the reason for the formation of many different soil types as well as the lower taxonomic units. These types of soils are characterized by different properties (chemical, physical, and physical-mechanical, productive). Therefore, they have varied effects on agricultural production. There are 9 different soil types and 18 complexes of more than two land types distributed in the Pčinja River basin together with a considerable amount of subtypes, varieties and forms. The most represented with the largest area are: Vertisol, Fluvisol, Fluvisol (Colluvial Soils) and Cambisol.