Determination of the eelationship between land use / land cover and soil organic matter in Samsun province

Abstract

Soil is one of the most important natural resources owing to its ecological, biological, economic and cultural functions. Therefore, agricultural land should be appropriately evaluated and used in accordance with its characteristics; moreover, it should be solely used for agricultural purposes. One of the most important factors affecting soil fertility is the amount of organic matter (OM). Therefore, the present study evaluated the distribution of OM in Samsun Province at Turkey’s Black Sea Region located in the Central Black Sea Department (total area: 9813 km 2 ), Turkey. A total of 971 soil samples were collected from the Samsun Province, and the amount of OM was assessed using a modified version of the Walkley–Black method. The distribution of OM was evaluated using an appropriate geostatistical method and a distribution map. The relationship between land cover/land use and the amount of OM was determined by applying a merging process using the geographic information systems program ArcGIS 10.2. The results revealed that rangelands had the highest amount of OM, followed by nonirrigated fruit regions, natural meadows, sparse plant regions, and continuously irrigated orchards. Furthermore, 85.8% of the land in Samsun Province comprised soils with a 2-3 percent of OM, 13.7% comprised soils with a 3-4 percent OM, and 0.5% comprised soils with a low amount of OM. Examination of the relationship between the existing land uses and the amount of OM showed that the soils in regions covered with broad-leaved forests and natural vegetation as well as agricultural and arable regions had sufficient amounts of natural flora and a low amount of OM; however, the soils in agricultural regions, nonirrigated arable regions, and nonirrigated mixed agricultural regions as well as regions covered with mixed forests had a medium amount of OM.