Агроэкологическая оценка почв под лесными насаждениями защитной зоны города Астаны

Abstract

Purpose of research – determine the influence of the degree of soil salinity on the state of hardwood plantations in the green zone of Nur-Sultan city The objects of research were forest plantations growing on soils with limited forest suitability. Artificial plantations of silver birch Betula pendula and Siberian elm Ulmus pumila in 2006 and 2010 of the same age class were selected for the study. Depending on the state of artificial plantations, soil tilling was carried out on the test plots at the depth of the root formation and soil samples were used for the analysis. It was revealed that there is diversity in the type of soil salinity across all sample plots and the most common one is chloride and sulfate salinity that is found in both healthy and weakened stands of both tree species. In chloride and sulfur chloride soil salinization, the physical state of birch plantations was signifi cantly reduced. The content of the sum of toxic salts in the soil under forest plantations of the Siberian elm in healthy stands was minimal, which was gradually increasing with the deterioration of the condition of the trees. In silver birch species, approximately the same content of the total salts was observed in healthy and deteriorated plantations, the increase in toxic salts contents was observed in weakened plantations. The height and diameter of trees in healthy stands of both tree species exceeded those of trees in weakened plantations, judging by the coefficient of variation, tree growth was heterogeneous. It was determined that for the Siberian elm the amount of salts of 0.057% is lethal, the salt content in the amount of 0.014% does not affect the decline in the condition and growth of trees. For the forest plantations of silver birch, contradictory results have been obtained, which require additional research.