PECULIARITIES OF HUMUS AND NITROGEN ECOLOGICAL STATE FOR STEPPE ZONE CHERNOZEMS OF THE NORTH CAUCASUS

Purpose of the paper presented is to determine tendency and intensity for quantitative and qualitative changes in humus and nitrogen of chernozems. System approach to study natural objects is assumed as the basis for research methodology of humus and nitrogen state of soils. It is established that the depth typical values of chernozem humus horizons in the North Caucasus are 120–180 cm for South European facies of leached chernozem, 100–170 cm for modal chernozems, 70–160 cm for common chernozems, 70–120 cm for sothern chernozems; for East European facies of southern chernozems it is 55–70 cm. A distinctive ecological feature of soils is a low humus content in an arable layer, its deep distribution along the profile and. slight variability among each subtype. Nitrogen quantity in chernozems of the region variates in comparatively wide ranges: in South European facies of leached, modal and common chernozems 0,20–0,35%, in East european facies of southern chernozems 0,22–0,30%. Southern chernozems of South European facies contain least of all nitrogen 0,18–0,22%. Tota1 nitrogen composition is presented in the main with nonhydrolysed facies – 74,2–78,9%. The research materials are intended to design farming systems on the landscape basis for specialists who are busy with the problem of conservation and increase in soil fertility and environment protection. The results of research allow to realize purposeful impact on decision making to control humus and nitrogen state of soils and this will serve as the basis for conservation of bioecological potential of chernozems.