Determination of catalase and urease activities of soil in Gaziantep/Araban

ABSTRACT DETERMINATION OF CATALASE AND UREASE ACTIVITIES OF SOIL IN GAZIANTEP/ARABAN ŞAHİN, Engin Zafer M.Sc. in Biology Supervisor: Assoc. Prof. Dr. Erdihan TUNÇ January 2020 74 pages Enzymes, which are biochemical catalysts in protein structure, are involved in the cycle of carbon (C), nitrogen (N), phosphorus (P), sulfur (S) and other nutrients both in nature and in agricultural areas. In soils, the catalase (peroxidase oxidoreductase, EC 1.11.1.6) is considered to be an indicator of aerobic and facultative anaerobic microbial activity. Also, the urease (urea amidohydrolase, EC 3.5.1.5) is considered as a marker of the nitrogen (N) cycle. This study was carried out in Araban (Gaziantep) to determine the relationships between physical and chemical parameters of soils and catalase and urease enzyme activities in three different agricultural areas. According to the results of the statistical analysis, catalase enzyme activity in pistachio (Pistacia vera L.) soil was positive and significant relationships (p <0.05) with soil salt content (%) and texture structure, whereas wheat soil (Triticum aestivum L.) was found negative and significant relationships (p <0.05) with soil texture. On the other hand, urease enzyme activity was positive and significant relationships (p <0,05) with organic pH (%), total nitrogen (N, %) content and soil texture in the pastures. In pistachio soils (Pistacia vera L.), urease was negative and significant relationships (p <0,05) with only organic matter content (%). Also urease was found positive and significant relationships (p <0.05), with lime (%) and total nitrogen (N, %) in wheat soils (Triticum aestivum L.) It was concluded that these differences occur as a result of different agricultural practices in different agricultural areas. Key Words: Soil Enzymes Activities, Agriculture, Catalase, Urease, Gaziantep