Establishing yeşi̇lirmak basin soil temperature database and researching possible relationships between soil temperature and geographic, topographic and some soil variables by geographic information systems

In this study, soil temperature data bases of Yeşilırmak Basin were established by two different methods as inverse distance weighted interpolation (IDW) and elevation dependent modeling in the the frame of geographic information systems (GIS). Thus, a total 70 digital databases including 35 raster intepolated and 35 raster model maps were produced for 5 different soil depth (5cm, 10cm, 20cm, 50cm and 100cm) and 7 five-year duration time periods (1982-1986, 1987-1991, 1992-1996, 1997-2001, 2002-2006, 2007-2011, 2012-2016). The databases obtained according to two different methods were compared according to the descriptive statistics results. In addition, the correlation of soil temperature databases with other soil variables (organic carbon, pH and Cation Exchange Capacity), topographic variables (elevation, slope, aspect) and geographic location (latitude, longitude) were investigated by correlation analysis. According to descriptive statistical evaluations, interpolation maps were considered more accurate than model maps. During the last 35 years, an increasing trend in the soil temperatures of Yeşilırmak Basin has been determined due to global warming. Correlation analyzes revealed that the independent variables showing