Sub DAS Soti merupakan salah satu Sub DAS hulu di DAS Progo. Masyarakat di Sub DAS Soti memiliki ketergantungan yang tinggi untuk kegiatan pertanian. Perubahan penggunaan lahan di daerah tangkapan air berpotensi mengganggu proses hidrologi seperti kapasitas infiltrasi. Tujuan penelitian ini adalah untuk menentukan porositas tanah, kapasitas infiltrasi dan hubungan antara porositas tanah dan kapasitas infiltrasi pada berbagai jenis penggunaan lahan. Pengukuran infiltrasi dan pengambilan sampel tanah dilakukan dengan purposive random sampling dengan sampel 27 titik menggunakan double ring infiltrometer. Profil vegetasi diselidiki menggunakan plot berukuran 7,5 x 60 meter. Hasil penelitian menunjukkan porositas tanah dan kapasitas infiltrasi dari berbagai penggunaan lahan: rumput (70,99%: 22,77 cm/jam); tegalan (63,06%: 21,61 cm/jam); belukar (64,49%: 24.53cm/jam); kebun (63,64%: 60,78 cm/jam); sawah tadah hujan (59,48%: 13,28 cm/jam) dan permukiman (54,31%: 17,37 cm/jam). Berdasarkan uji statistik, porositas tanah memiliki korelasi positif dengan kapasitas infiltrasi. Hubungan antara porositas tanah dan kapasitas infiltrasi ditunjukkan oleh persamaan Y = 1,6166x - 3,6312 dengan koefisien determinasi sebesar 0,0171

Soti catchment is one of the upstream catchment in the Progo watershed. Community in the Soti catchment has a high dependency for agricultural activities. The changes of land use in the catchment potentially disturb the hydrological processes such as infiltration capacity. The aims of this study is to determine the soil porosity, infiltration capacity and the relation between soil porosity and infiltration capacity of various types of land use. Infiltration measurement and soil sample collection were done by purposive random sampling with 27 point samples using double ring infiltrometer. Vegetation profile investigated using a plot measurement of 7.5 x 60 meters. The results showed the soil porosity and infiltration capacity of the various land uses: grass (70.99%: 22.77 cm/hour); upland (63.06%: 21.61 cm/hour); shrub (64.49%: 24.53cm/hour); garden (63.64%: 60.78 cm/hour); rainfed (59.48%: 13.28 cm/hour) and settlement (54.31%: 17.37 cm/hour). Based on the statistical test, the soil porosity has positive corelation with infiltration capacity. The relation between soil porosity and infiltration capacity is shown by the equation Y= 1,6166x - 3,6312 with the coefficient determination of 0,0171

Kata Kunci : Kapasitas Infiltrasi, Porositas Tanah, Penggunaan Lahan, Sub DAS Soti. 1 Mahasiswa