Judul: Analisis Sifat-Sifat Tanah pada Berbagai Umur Revegetasi Lahan Reklamasi Bekas Tambang Batubara PT Bukit Asam (Persero) Tbk
Abstrak: Reklamasi diatur dalam Undang-Undang Nomor 4 Tahun 2009 tentang Pertambangan Mineral dan Batubara. Penggunaan alat-alat berat dalam kegiatan reklamasi menyebabkan terjadinya pemadatan tanah. Selain itu, pada proses penimbunan kembali lubang bekas tambang batubara menggunakan alat-alat berat terjadi pencampuran antara top soil, sub soil dan bahan induk tanah. Pencampuran ini mengakibatkan sifat fisik, kimia, dan biologi tanah berubah. Penelitian ini bertujuan untuk menganalisis perubahan sifat fisik, kimia, dan biologi tanah dengan adanya peningkatan umur revegetasi lahan reklamasi bekas tambang dan membandingkannya dengan lahan hutan. Penelitian ini dilakukan di lahan reklamasi bekas tambang batubara umur revegetasi 0, 4, dan 7 tahun IUP Banko Barat PT Bukit Asam (Persero) Tbk Tanjung Enim, Kabupaten Muara Enim, serta lahan hutan. Hasil penelitian menunjukkan bahwa kualitas tanah secara umum mengalami perubahan menjadi relatif lebih baik pada sebagian sifat-sifat tanah dengan adanya peningkatan umur revegetasi. Beberapa sifat tanah yang mencakup bobot isi, kapasitas infiltrasi, porositas tanah, C-organik, N-total, P-tersedia, total mikrob dan respirasi tanah mengalami perbaikan terutama pada kedalaman 0-20 cm untuk sifat fisik tanah dan kedalaman 0-5 cm untuk sifat kimia tanah, serta kedalaman 0-10 cm untuk sifat biologi tanah. Beberapa sifat-sifat tanah lainnya mencakup pH, KTK, basa-basa dapat ditukar, dan KB bervariasi diduga lebih dikarenakan variabilitas bahan timbunan pada awal reklamasi. Peningkatan kualitas tanah reklamasi tersebut masih lebih rendah dibandingkan dengan kualitas tanah hutan.
Keyword: Air asam tambang, hara makro, infiltrasi, total mikrob

Judul: Analisis Sifat Fisik, Kimia, dan Biologi Tanah pada Lahan Reklamasi Bekas Tambang Batubara PT Berau Coal Site Binungan, Kabupaten Berau, Provinsi Kalimantan Timur
Abstrak: Soil degradation becomes the greatest problem of environmental damage due to coal mining, in particular by open pit method. Proper reclamation must be done to repair post mining land so that soil quality can be recovered approaching the original properties. To analyze the results of the reclamation process on physical, chemical, and biological soil properties changes and their development, it is necessary to study the changes of soil properties at different ages post coal mining land reclamation. This research was aimed to identify the changes of physical, chemical, and biological soil properties in relation to increased reclamation age (0, 3, 6, and 9 years old) and compared them to the nearby forest soil properties. This research was conducted in reclaimed post coal mining lands of PT Berau Coal Site Binungan, East Kalimantan Province (aged 0, 3, 6, and 9 years), and native forest. Soil analysis performed at the Laboratory of Chemical and Soil Fertility, Laboratory of Soil Physics, and Laboratory of Soil Biotechnology, Department of Soil Science and Land Resources, Faculty of Agriculture, Bogor Agricultural University. The results showed that increasing age causes changes in soil properties of reclaimed land approaching the soil properties of original land. This can be seen on the parameters such as bulk density, infiltration capacity, aluminum saturation, C-organic, total N, base saturation, Cation Exchange Capacity (CEC), total microbial and fungal, and soil respiration. It is apparent that chemical and biological soil properties on reclaimed land change relatively faster approaching the chemical and biological soil properties of the original land compared to that of physical soil properties.
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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