Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

Soil classification of Ataturk Arboretum (Istanbul) According to the World

Reference Base for Soil Resources
Soils provide many benefits to humans, especially as food and housing. For this reason, the soils are tried to be classified according to their production capacity for thousands of years. At this classification which is also called as ‘Ecological soil classification’, soils are grouped in accordance with their characteristics (stoniness, physical depth and soil type) that influence plant growth. In the last few centuries, the soils are classified according to the process of formation and development and it is called as ‘Genetic soil classification’.
There are different approaches to the genetic classification of soils. The most common approach is the system known as Soil Taxonomy which was developed by United States Department of Agriculture (USDA). Apart from this, an other classification approach which its principles introduced in Germany is also quite common, and it is called as Central European Approach. In addition, some countries have also developed their own soil classifications according to their ecological features. In Turkey, soil systematic is used for classification of agricultural lands and Central European Systematics for the classification of forests. Different approaches to the classification of soils has led to the emergence of various difficulties. For this reason, a new soil classification system which is called World Reference Base for Soil Resources (FAO / WRB) has been developed by the Food and Agriculture Organization (FAO). In this classification, updated from time to time, diagnostic horizons which are based on U.S. system are used on the definitions, but the nomenclature of the soils are used in accordance to different languages. It is also essential to say, European Comission has decided that the classification of the European land soils is to be processed according to FAO/WRB.
Being a fairly new classification system of FAO / WRB, quite a few studies have been conducted in Turkey. Almost entire of this few studies have been made on agricultural lands. Therefore, Atatürk Arboretum in Istanbul is selected as the research area, and it is aimed here to determine the existence of the possible reference soil groups and the soil units according to FAO / WRB classification system.
Firstly, soil samples were taken by soil probes in a systematic grid net of 250 x 250 m and different horizons have been determined. Then, at a total of 13 soil profile pits, general data on the shape of ground features (slope, aspect, relief, elevation, etc.), parent material, soil type, physiological and the absolute depths of the soil, closure status of the plants, coverage degree of the trees and brushes, outer soil state and the thickness of litter, the thicknesses of the horizons within transition limits with neighbouring horizons, color of the soil (according to Munsell Soil Color Chart), spotting, stoniness, soil type and structure have been recorded on relevant charts. Later, soil samples from allotted horizons on the area were taken. On these samples, bulk density, pH, CaCO3, texture, total nitrogen, organic carbon, exchangeable cations, changable acidity, cation exchange capacity, base saturation have been determined in laboratory works.
By means of those soil properties determined and diagnosed in field and laboratory, 5 different reference soil groups in accordance with FAO/WRB classification system have been classified in Ataturk Arboretum which are Stagnosols, Luvisols, Cambisols, Alisols and Acrisols.