Soil organic matter content and composition in different pedoclimatic zones of Bulgaria

Abstract

The present paper focused on content, quality and composition of soil organic matter indifferent pedoclimatic zones of Bulgaria. The country has temperate continentalclimate with Mediterranean influence. There are six combinations of soil temperatureand moisture regimes over the territory of Bulgaria, such as Thermic-Xeric, MesicXeric, Mesic-Ustic, Mesic-Udic, Cryic-Udic and Pergelic – Udic. Typical soil types forBulgaria are Chernozems, Luvisols. Vertisols, Cambisols, Phaeozems, Leptosols,Regosols, Planosols, Umbrisols and etc. Fifteen soil profiles were studied which arerepresentative for the area. The content and composition of organic matter weredetermined according to the method of Kononova-Belchikova. The purpose of thisstudy is to determine the influence of pedoclimatic conditions over soil organic mattercontent and composition of various areas with different soil cover, vegetation,management and etc. Grouping soil types in different soil temperature and moistureregimes shows that there are similarities in soil carbon content and composition. Soilsdeveloped under cooler and moister conditions accumulate more organic carbon. Insuch areas the content of organic carbon can reach about 255 t.ha-1 in a surface horizonand the type of humus is predominantly Fulvic. Respectively, soils developed under dryand warmer conditions have lower organic carbon content and the type of humus isusually Humic.