Electronic Theses and Dissertation

Tanaman Kopi merupakan salah satu komoditas perkebunan yang memiliki nilai
ekonomis yang cukup tinggi, sehingga memegang peranan penting dalam perekonomian
Indonesia. Perkembangan dan pertumbuhan tanaman kopi sangat tergantung pada
karakteristik kimia, sifat fisika dan sifat biologi serta kondisi iklim dan pengelolaan tanaman.
Salah satu indikator untuk menentukan kualitas dan tingkat kesuburan tanah serta
ketersediaan hara yang digunakan sebagai rekomendasi kimia tanah. Kemiringan lahan juga
dapat mempengaruhi kualitas kimia tanah terutama pada tanah permukaan, namun
pertumbuhan kopi juga dipengaruhi oleh kualitas tanah di bawah permukaan, sehingga
informasi tentang sifat kimia tanah lapisan bawah juga perlu diketahui.
Penelitian ini bertujuan untuk mengetahui karateristik kimia tanah lapisan bawah
pada berbagai tingkat kemiringan lahan di Perkebunan Kopi Arabika di Kecamatan Ketol
Kabupaten Aceh Tengah. Analisis tanah dilakukan di Laboratorium Penelitian Tanah dan
Tanaman Fakultas Pertanian Universitas Syiah Kuala, Banda Aceh. Penelitian dilakukan
sejak Februari hingga April 2024 menggunakan metode deskriptif kuantitatif melalui survei
lapangan dan analisis laboratorium. Pengambilan sampel tanah dilakukaan dengan bor tanah
pada kedalaman 20-40 cm pada Perkebunan kopi rakyat mewakili empat kelas kemiringan
lahan (lereng) yaitu: 0-8% (datar hingga landai), 8-15% (berbukit), 15-25% (bergelombang),
dan 25-40% (bergunung). Setiap kelas lereng diambil 5 sampel secara acak, kemudian
dikompositkan menjadi satu subsample untuk dianalisis di laboratorium. Parameter kimia
tanah yang dianalisis meliputi: pH H2O (metode elektrometrik), C organik (metode Walkley
& Black), N total (metode Kjeldahl), P2O5 dan K2O total (ekstraksi HCl 25%), serta kapasitas
tukar kation (KTK) (metode 1N NH4COOCH3 pH7).
Hasil penelitian menunjukkan bahwa karakteristik kimia tanah lapisan bawah di
Perkebunan Kopi Arabika Kecamatan Ketol Kabupaten Aceh Tengah secara umum kurang
baik karena terdapat beberapa kendala kimia tanah dan bervariasi antara tingkat kemiringan
lahan. Reaksi tanah (pH H2O) termasuk dalam kriteria masam hingga agam masam, C-
organik termasuk ke dalam kriteria rendah hingga sangat rendah, N-total termasuk ke dalam
kriteria rendah, P2O5 total termasuk ke dalam kriteria sedang hingga sangat tinggi, K2O total
termasuk ke dalam kriteria sedang hingga tinggi, dan kapasitas tukar kation (KTK) termasuk
ke dalam kriteria rendah. Berdasarkan karakteristik kimia tersebut maka yang menjadi
masalah (kendala) pada tanah lapisan bawah di Perkebunan Kopi Arabika di daerah ini
adalah kemasaman tanah, kandungan C organik, N total, dan KTK, sehingga dibutuhkan
penambahan bahan organik dan bahan amandemen lainnya serta perlu tindakan konservasi
kualitas tanah lapisan bawah dapat diperbaiki.

Coffee plants are one of the plantation commodities that have value economical is quite high, so it plays an important role in the economy Indonesia. The development and growth of coffee plants depends greatly on chemical characteristics, physical and biological properties as well as climatic conditions and plant management. One of the indicators to determine the quality and level of soil fertility as well Nutrient availability is used as a recommendation for soil chemistry. The slope of the land too can affect soil chemical quality especially on surface soils, however Coffee growth is also influenced by the quality of the soil below the surface, so information about the chemical properties of the subsoil also needs to be known. This research aims to determine the chemical characteristics of the subsoil at various levels of land slope on Arabica Coffee Plantations in Ketol District Central Aceh Regency. Soil analysis was carried out at the Soil Research Laboratory and Plants, Faculty of Agriculture, Syiah Kuala University, Banda Aceh. Research conducted from February to April 2024 using quantitative descriptive methods through surveys field and laboratory analysis. Soil samples were taken using a soil drill at a depth of 20-40 cm on people's coffee plantations representing four slope classes land (slope), namely: 0-8% (flat to sloping), 8-15% (hilly), 15-25% (wavy), and 25-40% (mountainous). For each slope class, 5 samples were taken randomly, then composited into one subsample for analysis in the laboratory. Chemical parameters The soil analyzed includes: pH H2O (electrometric method), organic C (Walkley method & Black), total N (Kjeldahl method), total P2O5 and K2O (25% HCl extraction), as well as capacity cation exchange (CEC) (1N NH4COOCH3 pH7 method). The results showed that the chemical characteristics of the subsoil in Arabica coffee plantations in Ketol District, Central Aceh Regency are generally lacking good because there are several soil chemical constraints and it varies between slope levels land. The soil reaction (pH H2O) is included in the criteria of acidic to acidic acid, C- organic is included in the low to very low criteria, N-total is included low criteria, total P2O5 is included in the medium to very high criteria, total K2O included in the medium to high criteria, and cation exchange capacity (CEC) included into the low criteria. Based on these chemical characteristics, it becomes problems (constraints) in the subsoil on Arabica Coffee Plantations in this area are soil acidity, organic C content, total N, and CEC, so they are needed addition of organic materials and other amendments and the need for conservation measures the quality of the subsoil can be improved.