Kajian Tekstur, C-Organik, dan pH Tanah Ultisol pada BeberapaVegetasi di Desa Gunung Datas Kecamatan Raya Kahean (Study Kasus : Lahan Agak Kritis di Wilayah Sub DAS Bah Sumbu) : Study of Texture, Organic Carbon, and Acidity of Ultisols in Several Vegetations at Gunung Datas Village Raya Kahean Sub District (Case Study: Semi Critical Land Bah Sumbu Sub Watershed)

Land use at the area of Bah Sumbu Sub Watershed has intensified, causing the decrease of soil organic matter. The land area with criteria critically / semi critically at Bah Sumbu subwatershed area is 8742,949 hectares or 79.41% of the total entire Bah Sumbu Sub Watershed. This research was conducted to study texture, organic carbon and acidity of the soil moderate critical area of land at Bah Sumbu sub-Watershed, Gunung Datas , Raya Kahean Subdistrict. The research was conducted by using a survey method with soil sampling randomly based on some vegetations and slopes. Soil samples were taken at each vegetation for 3-6 samples. Analyzed of soil pH with methods electrometry, soil organic matter with Walkley and Black method, and soil texture with Hydrometer Bouyoucos method. Based on the results of soil analysis of several lands uses in Gunung Datas Village, Bah Sumbu subwatershed area is known that soil pH is included in very acidic to slightly acidic criteria with acidity range of 3.73 to 5.82. The C-organic content is included in very low to moderate criteria with a range of organic carbon between 0.77% to 2.02%, and the texture is dominant sandy loam soil texture. Penggunaan lahan di areal Sub DAS Bah Sumbu sudah semakin intensif sehingga mengakibatkan penurunan bahan organik tanah. Luas lahan dengan kriteria agak kritis/semi kritis di sub DAS Bah Sumbu seluas 8742,949 hektar atau 79,41 % dari total seluruh wilayah sub das Bah Sumbu. Penelitian ini bertujuan untuk mengkaji tekstur, karbon organik dan kemasaman tanah pada wilayah lahan agak kritis di wilayah sub das Bah Sumbu desa Gunung Datas Kecamatan Raya Kahean. Penelitian dilakukan dengan menggunakan metode survey dengan pengambilan sampel tanah secara acak berdasarkan beberapa vegetasi dan lereng. Sampel tanah diambil pada masing-masing vegetasi sebanyak 3-6 sampel. Analisis pH tanah dilakukan dengan metode elektrometri, karbon organik dengan metode Walkley and Black, dan tekstur dengan metode Hydrometer Bouyoucos. Berdasarkan hasil analisis tanah dari beberapa penggunaan lahan di Desa Gunung Datas kawasan Sub-DAS Bah Sumbu diketahui bahwa pH tanah termasuk dalam kriteria sangat masam sampai agak masam dengan rentang pH 3,73 sampai dengan 5,82. Kandungan C-organik termasuk dalam kriteria sangat rendah sampai sedang dengan rentang kandungan c-organik antara 0,77% sampai dengan 2,02%, dan dominan tekstur tanah adalah lempung berpasir. Kat