Sifat Fisik Tanah dan Hubungannya dengan Kapasitas Infiltrasi DAS Tamiang

Cut Azizah Jakfar (IPB University Universitas Almuslim Aceh)
Hidayat Pawitan (Department of Geophysical and Meteorology, Faculty of Mathematics and Natural Sciences, IPB University, West Java, Bogor, 16680, Indonesia)
Bambang Dwi Dasanto (Department of Geophysical and Meteorology, Faculty of Mathematics and Natural Sciences, IPB University, West Java, Bogor, 16680, Indonesia)
Iwan Ridwansyah (The Indonesian Institute of Sciences, West Java, Cibinong, 16911, Jakarta, Indonesia)
Muh Taufik (Department of Geophysical and Meteorology, Faculty of Mathematics and Natural Sciences, IPB University, West Java, Bogor, 16680, Indonesia)

Jurnal Tanah dan Iklim
Vol 43, No 2 (2019)

Abstrak. Daerah Aliran Sungai (DAS) Tamiang merupakan wilayah rawan bencana dan digolongkan sebagai DAS kritis di Indonesia karena rawan banjir. Mitigasi banjir memerlukan analisis kuantifikasi limpasan yang diprediksi dari curah hujan dikurangi kapasitas infiltrasi. Penelitian ini bertujuan untuk mengetahui distribusi parameter fisik tanah dan hubungannya dengan kapasitas infiltrasi DAS Tamiang. Parameter fisik tanah yang dianalisis adalah tekstur tanah, berat jenis, kadar air, permeabilitas dan porositas. Hasil penelitian menunjukkan tekstur tanah didominasi clay sehingga Hydrologic Soil Grups (HSG) termasuk dalam kapasitas infiltrasi sedang, berat jenis tanah 0,9-1,5 g cm-3, nilai kadar air  pada musim kemarau 20-78 % (volume), nilai permeabilitas termasuk kategori sedang dan agak cepat (3-8 cm jam-1), dan nilai porositas 44-68%. Distribusi parameter fisik tanah menunjukkan kualitas yang kurang baik untuk kapasitas infiltrasi DAS Tamiang. Hasil penelitian dapat digunakan pada perencanaan pengelolaan sumberdaya air yang memerlukan data tanah untuk penelitian terkait. Abstract. The Tamiang River Basin is one of a disaster-prone and considered as a critical area in Indonesia due to vulnerability to flood. Flood mitigation requires an analysis of runoff quantification derived from the difference between rainfall and infiltration capacity. This study aimed to determine the distribution of soil physical parameters and their relationship to the infiltration capacity of the Tamiang watershed. Soil physical parameters analyzed were soil texture, bulk density, moisture content, permeability and porosity. The results showed the texture of the soil was predominantly clay so that the Hydrologic Soil Grups (HSG) was included in the medium infiltration capacity group, soil bulk density was 0.9-1.5 g cm-3, water content in the dry season was 20-78% (by volume), permeability belonged to medium and fairly fast categories (3-8 cm hour-1), and the porosity is was 44-68%. The distribution of soil physical parameters indicate somewhat poor infiltration capacity of the Tamiang watershed. The results of this study can be used in water resources management planning that requires soil data for related research