The Contemporary State of the Humus Nutrion of the Cambisols of Republic of Armenia

Abstract

According to the upward zonality the forest brown soils occupy the northeastern part of the republic; the mountain slopes of 1300-2250m above sea level. The criteria presented in the World Reference Base for Soil Resources (WRB) have been adopted as the classification criteria for all genetic soil-types and subtypes of the Republic. According to this classification, the brown soils of the forest correspond to the name cambisols. The humus of Republic of Armenia cambisols has been studied. It turned out that these soils are characterized by high content of humus; up to 11,2%, which gradually decreases parallel with the soil profile depth. The humus content in plant litter reaches up to the 21,8%. One of the most important features in the cambisols is a high hydrolysis character of humus. The total balance of carbon of humus substances is 17.0-43.6%, which shows the weak linkage of humus with the mineral part of the soil. In general the presence of black HA in the content of humin acids is not typical for cambisols. It is well known that in forest grey soil prevail FA and grey FA and the absence of HA, which are combined with exchanging Ca, moving R 2 O 3 - as well as with the acid reaction of the soil, which consider being main connectors of humic substances. Fulvic acids and brown humic acids prevail in the content of humic acids. The soils are characterized with considerable amount of black humic acids and low optical density of humic acids in the low horizons. There are subtypes differences in the content and features of forest grey soils, which is due to the narrow ratio of Cha: Cfa in strong unsaturated subtype soils. Grey humic acids prevail in the content of humic acids, and the humic acids have low optical density.