Hubungan Antara Penggunaan Lahan Dan Kemiringan Lereng Terhadap Erodibilitas Tanah di Samigaluh, Kulonprogo

MUHAMMAD DARUSSALAM TEGUH, Prof. Dr. Ir. Supriyanto Notohadisuwarno, M.Sc.; Ir. Suci Handayani, M.P.

2017 | Skripsi | S1 ILMU TANAH

Penelitian ini bertujuan untuk mengetahui erodibilitas tanah, pengaruh hubungan antara penggunaan lahan dan kemiringan lereng terhadap erodibilitas tanah, serta memetakan tingkat erodibilitas di Kecamatan Samigaluh. Titik pengambilan sampel tanah berjumlah 52 titik yang dilakukan berdasarkan tipe penggunaan lahan meliputi kebun, semak/belukar, sawah tadah hujan dan tegalan di kemiringan lereng 4-8%, 8-15%, 15-25% dan 25-45%. Hasil penelitian menunjukkan bahwa tanah pada tempat penelitian adalah Inceptisol, tipe penggunaan lahan dan kemiringan lereng tidak ada interaksi yang nyata terhadap nilai erodibilitas tanah. Nilai erodibilitas tanah di Kecamatan Samigaluh paling tinggi terdapat pada tipe penggunaan lahan sawah tadah hujan di kemiringan lereng 25-45% dengan nilai 0,38. Sedangkan nilai erodibilitas tanah paling rendah terdapat pada tipe penggunaan lahan sawah tadah hujan di kemiringan 8-15% dengan nilai 0,20. Erodibilitas tanah pada Kecamatan Samigaluh berada pada kelas rendah sampai agak tinggi. Hal ini dipengaruhi oleh kandungan tekstur tanah yang terdiri atas 25-45% fraksi lempung, 23-51% fraksi debu, dan 13-33% fraksi pasir, memiliki struktur gumpal, bahan organik berkisar 1,73-3,50%, dan kelas permeabilitas sangat lambat sampai sedang. Luasan nilai erodibilitas rendah sebesar 116,10 ha, erodibilitas sedang sebesar 3035,31 ha, dan erodibilitas agak tinggi sebesar 1238,48 ha.

This research aims to determine the index of soil erodibility, the relations between land use and slope with soil erodibility, and mapping the level of soil erodibility in Samigaluh Subdistrict. Fifty two soil samples were collected based on soil mapping unit that of the overlays of landuse and slopes steeps. The results showed that the soil type at the site of research was Inceptisols, types of land use and slopes there didn't significantly affect soil erodibility. Soil erodibility index in Samigaluh Subdistrict was highest in land use types the rainfed lowland in the slope of 25-45% with a value of 0,38, whereas the lowest index of the erodibility was found in the use of the rainfed lowland in slope 8-15% with a value of 0,20. Soil erodibility at Samigaluh Subdistrict class low to rather high, it was influenced by the content of soil texture consisting of 25-45% fraction of clay, 23-51% fraction of silt, and 13-33% fraction of sand, has a structure of blocky, organic matter ranging from 1,73-3,50%, and has a very slow to moderate permeability. Soil with low erodibility value was 116,10 ha, a moderate soil erodibility was 3035,31 ha, and a rather high soil erodibility was 1238,48 ha.

Kata Kunci : erodibilitas, tipe penggunaan lahan, kemiringan lereng