Rosmalia,2014. Analisis Penyimpanan Biomassa Karbon Pada Berbagai Penggunaan Lahan Di Kecamatan Lembah Seulawah Kabupaten Aceh Besar. Tesis Magister, Program Pascasarjana Universitas Syiah Kuala, dibawah bimbingan Ashabul Anhar dan Muyassir. ABSTRAK Penelitian ini bertujuan untuk mengetahui kemampuan penyimpanan biomassa karbon atas maupun bawah permukaan tanah dan untuk mengetahui penyimpanan biomassa karbon pada berbagai tipe penggunaan lahan, dengan lua sobjek penelitian1100 ha. Penelitian ini dilaksanakan selama 3 (tiga) bulan. Penelitian ini menggunakan metode allometrik dengan menggunakan rumus W = aDb (Brown 1997) pada lahan hutan sekunder, pada lahan agroforestri dan monokultur menggunakan metode destruktif, C organik tanah menggunakan metode Walkley dan Black. Analisa sampel dilakukan di laboratorium Analisa Tanah Fakultas Pertanian Universitas Syiah Kuala dan Laboratorium Balai Pengkajian Teknologi Pertanian Banda Aceh. Hasil penelitian menunjukkan bahwa jumlah cadangan karbon terbesar terdapat pada lahan hutan sekunder yakni sebesar 241,36 ton/ha, diikuti agroforestri sebesar 66,00 ton/ha, monokultu r32,33 ton/ha sedangkan kandungan karbon terkecil terdapat pada tanaman semusim yakni sebesar 2,36 ton/ha. Kandungan C organic tanah terbesar terdapat pada lahan hutan sekunder yaitu 6,82 ton/ha, diikuti dengan agroforestri 3,98 ton/ha, monokultur 3,31 ton/ha dan kandungan bahan organik tanah terendah terdapat pada tanaman semusim yaitu 2,44 ton/ha. Besarnya cadangan karbon dan kandungan bahan organik tanah pada suatu lahan dipengaruhi oleh tingginya populasi. Kata Kunci :Biomassa karbon, C organik tanah, agroforestri, monokultur Rosmalia, 2014. Analysis of Biomass Carbon Storage in various Land Use in Subdistrict Lembah Seulawah Aceh Besar. Thesis Masters, Graduate Program of Syiah Kuala University, under guidance of Ashabul Anhar and Muyassir. ABSTRACT This research aims to study the ability of biomass carbon storage above and below ground in different land use. This research was carried out in three months with the areas of the study of 1100 ha. The allometric method was appliedin this study with the formula of W = aDb (Brown 1997) in the secondary forest areas, and the destructive methods was usedin the agroforestry and monoculture areas. Soil organic C using Walkley and Black. The analysis of soil samples was carried out in the Laboratory of Agriculture Faculty, Syiah Kuala University and in the Laboratory of Agency for Agricultural Research, Banda Aceh. The results showed that the highest amount of carbon storage in the secondary forest land 241,36 ton/ha, followed by in the agroforestry areas 66,00 ton/ha and monoculture areas 32,33 ton/ha, whereas the lowest carbon storage was found in the annual crops 2,36 ton/ha. The highest content of soil organic matter was found in the secondary forest land 6,82 ton/ha, followed by the agroforestry areas 3,98 ton/ha and the monoculture3,31 ton/ha, while the lowest soil organic matter content was found in the annual crops 2,44 ton/ha. The amount of carbon stocks and soil organic matter on a farm is affected by high of population. Key words: Biomass carbon, soil organic-C, agroforestry, monoculture