Electronic Theses and Dissertation

Kopi Arabika merupakan komoditi yang dibudidayakan oleh masyarakat di Kabupaten Aceh Tengah dan Bener Meriah. Hal ini dikarenakan kedua kabupaten tersebut memiliki ketinggian yang sesuai dengan syarat tumbuh tanaman kopi Arabika. Secara geografis, di Kabupaten Bener Meriah terdapat salah satu gunung api aktif. Aktivitas dari gunung api dapat menghasilkan abu vulkanik yang merupakan salah satu bahan induk tanah Andisol. Akan tetapi, seiring berjalannya waktu tanah Andisol dapat berubah menjadi tanah Alfisol, Inceptisol, Ultisol, dan Oxisol akibat terjadinya pelapukan di daerah beriklim tropis. Tujuan dari penelitian ini yaitu mengkaji karakteristik dan klasifikasi tanah pada setiap pedon di areal yang ditanami kopi Arabika di Dataran Tinggi Gayo (Kabupaten Aceh Tengah dan Bener Meriah).
Metode yang digunakan dalam penelitian ini yaitu metode survai deskriptif-kuantiatif di Kabupaten Aceh Tengah dan Kabupaten Bener Meriah. Prosedur penelitian ini terdiri dari delapan tahapan yaitu pengumpulan literatur, pengolahan data sekunder yaitu peta administrasi dan peta jenis tanah, pembuatan dan pengamatan profil tanah, penetapan klasifikasi tanah sementara, pengambilan sampel tanah di lapangan, analisis tanah di laboratorium (pH H2O, pH KCl, pH NaF, C-organik, kation basa dan asam tanah dapat ditukar, KTK, KTK liat, KB, EA, retensi fosfat, P total, P tersedia, N total, tekstur tanah, bobot isi, kadar air tanah), penetapan karakteristik tanah, dan penetapan klasifikasi tanah definitif menggunakan sistem Taksonomi Tanah (SSS, 2014).
Karakteristik tanah berbeda-beda pada setiap pedonnya. Warna matriks tanah beragam dari warna hitam hingga kuning kecoklatan dengan hue dari 5YR sampai 10YR. Pedon I, II, dan IV adalah memiliki kelas tekstur liat dan kadar C-organik pedon I (1,18 - 2,06%), II (0,32 - 2,56%), dan IV (0,83 - 3,24%) tergolong rendah. Pedon III dan V memiliki kelas tekstur lempung hingga lempung berpasir, nilai bulk density pedon III (0,66 g cm-3¬¬) dan V (0,72 g cm-3¬¬), kadar C-organik pedon III (5,51 - 6,59%) dan V (1,79 - 13,36%) tergolong tinggi, memiliki pH NaF > 10, dan memiliki P retensi antara 85 - 97%. Pedon I (9,12 - 148,84%) memiliki KB yang tinggi, tetapi memiliki KTK pedon I (2,0 - 20,1 cmol(+) kg-1) yang rendah. Pedon II (9,44 - 18,74%), III (28,31 - 34,01%), IV (25,89 - 34,9%), dan V (10,2 - 21,72%) memiliki KB yang rendah dan KTK pedon II (13,1 - 16,8 cmol(+) kg-1), III (19,3 - 22,7 cmol(+) kg-1), IV (2,5 - 10,9 cmol(+) kg-1), dan V (14,0 - 24,2 cmol(+) kg-1) juga rendah.
Hasil analisis mengelompokkan kelima pedon ini menjadi tiga ordo tanah, yaitu Inceptisol (pedon I dan pedon II) karena memiliki horison kambik, Andisol (pedon III dan pedon V) karena memiliki sifat tanah andik 60% atau lebih di dalam 60 cm, dan Ultisol (pedon IV) karena memiliki horison kandik. Pedon I memiliki epipedon okrik (tebal 15 cm; warna 10YR 3/4; KB 57,37%; C-organik sebesar 2,06%), horison kambik (tebal 16 cm; tekstur liat; kandungan liat lebih tinggi dibanding horison di bawahnya), ordo Inceptisol (memiliki horison kambik), subordo Udepts (Inceptisol yang lain), great group Eutrudepts (KB > 50%), dan subgrup Ruptic-Alfic Eutrudepts (memiliki horison kambik). Pedon II memiliki epipedon okrik (tebal 20 - 34 cm; warna 10YR 4/6; KB 18,74%; C-organik sebesar 2,56%), horison kambik, ordo Inceptisol, subordo Udepts, great group Dystrudepts (KB < 50%), dan subgrup Ruptic-Ultic Dystrudepts (memiliki horison kambik). Pedon III memiliki epipedon melanik (sifat tanah andik; warna 10YR 2/2; C-organik ≥ 4% setiap horison), horison sombrik (KTK liat 0,86 cmol(+) kg-1; KB 33,89%; value warna lebih rendah dari atasnya (10YR 2/1)), subordo Udands (Andisol yang lain), great group Melanudands (epipedon melanik), dan subgrup Typic Melanudands (Melanudands yang lain). Pedon IV memiliki epipedon umbrik (tebal 22 cm; value warna 2/2; KB 34,9%; C-organik 3,24%), horison kandik (iluviasi liat 34% dan KTK 10,9 cmol(+) kg-1), subordo Humults (C-organik 1,49%), great group Kanhaplohumults (memiliki horison kandik), subgrup Typic Kanhaplohumults (Kanhaplohumults yang lain). Pedon V memiliki epipedon umbrik (tebal 37 cm; warna 2,5/1; KB 21,72%; C-organik 13,36%), horison kandik (iluviasi liat 5%; KTK 14,0 cmol(+) kg-1; C-organik menurun), subordo Udands, great group Hapludands (Udands yang lain), dan subgrup Ultic Hapludands (memiliki horison kandik dan KB < 35%).

Arabica coffee is a commodity that is cultivated by people in Aceh Tengah and Bener Meriah Regencies. This is because the two districts have heights that are in accordance with the requirements for growing Arabica coffee plants. Geographically, Bener Meriah Regency has an active volcano. Volcanic activity can produce volcanic ash which is one of the main ingredients of Andisol soil. However, over time, Andisol soils can change into Alfisols, Inceptisols, Ultisols, and Oxisols due to weathering in tropical climates. The purpose of this study was to examine the characteristics and classification of soil in each pedon in an area planted with Arabica coffee in the Gayo Highlands (Aceh Tengah and Bener Meriah Regencies). The method used in this study is a descriptive-quantitative survey method in Aceh Tengah District and Bener Meriah District. The research procedure consisted of eight stages, namely collecting literature, processing secondary data, namely administrative maps and soil type maps, preparing and observing soil profiles, determining temporary soil classification, taking soil samples in the field, analyzing soil in the laboratory (pH H2O, pH KCl, pH NaF, C-organic, alkaline and acid exchangeable soil cations, CEC, clay CEC, KB, EA, phosphate retention, total P, available P, total N, soil texture, bulk density, soil water content), determination of soil characteristics , and determination of definitive soil classification using the Soil Taxonomy system (SSS, 2014). Soil characteristics vary in each pedon. The color of the soil matrix varies from black to yellow-brown with hues from 5YR to 10YR. Pedon I, II, and IV have a clay texture class and C-organic content of pedon I (1.18 - 2.06%), II (0.32 - 2.56%), and IV (0.83 - 3.24%) is low. Pedon III and V have clay to sandy loam texture classes, bulk density values of pedon III (0.66 g cm-3) and V (0.72 g cm-3), pedon III organic C content (5 .51 - 6.59%) and V (1.79 - 13.36%) were classified as high, had a pH of NaF > 10, and had a retention P between 85 - 97%. Pedon I (9.12 - 148.84%) has a high KB, but has a low CEC of pedon I (2.0 - 20.1 cmol(+) kg-1). Pedon II (9.44 - 18.74%), III (28.31 - 34.01%), IV (25.89 - 34.9%), and V (10.2 - 21.72%) had low KB and CEC pedon II (13.1 - 16.8 cmol(+) kg-1), III (19.3 - 22.7 cmol(+) kg-1), IV (2.5 - 10, 9 cmol(+) kg-1), and V (14.0 - 24.2 cmol(+) kg-1) is also low. The analysis results grouped these five pedons into three soil orders, namely Inceptisols (pedons I and II) because they have a cambic horizon, Andisols (pedons III and V) because they have andic soil properties of 60% or more within 60 cm, and Ultisols (pedons IV) because it has a kandic horizon. Pedon I has an ochric epipedon (thickness is 15 cm; color 10YR 3/4; KB 57.37%; C-organic 2.06%), cambic horizon (thickness is 16 cm; clay texture; clay content higher than the underlying horizon), order Inceptisol (has a cambic horizon), suborder Udepts (other Inceptisols), great group Eutrudepts (KB > 50%), and subgroup Ruptic-Alfic Eutrudepts (has a cambic horizon). Pedon II has an ochric epipedon (thickness is 20 - 34 cm; color 10YR 4/6; KB 18.74%; C-organic 2.56%), cambic horizon, order Inceptisol, suborder Udepts, great group Dystrudepts (KB < 50 %), and the subgroup Ruptic-Ultic Dystrudepts (having a cambic horizon). Pedon III has a melanic epipedon (andic soil properties; color 10YR 2/2; C-organic ≥ 4% per horizon), sombric horizon (clay clay 0.86 cmol(+) kg-1; KB 33.89%; color value lower than above (10YR 2/1)), suborder Udands (other Andisols), great group Melanudands (melanic epipedon), and subgroup Typic Melanudands (other Melanudands). Pedon IV has an umbric epipedon (thickness is 22 cm; color value 2/2; KB 34.9%; C-organic 3.24%), kandic horizon (34% clay illuviation and CEC 10.9 cmol(+) kg-1), suborder Humults (C-organic 1.49%), great group Kanhaplohumults (has a kandic horizon), subgroup Typic Kanhaplohumults (another Kanhaplohumults). Pedon V has an umbric epipedon (thickness is 37 cm; color 2.5/1; KB 21.72%; C-organic 13.36%), kandic horizon (5% clay illuviation; CEC 14.0 cmol(+) kg-1; C-organic decreases), suborder Udands, great group Hapludands (other Udands), and subgroup Ultic Hapludands (having a kandic horizon and KB < 35%).