Judul: Produktivitas, Laju Dekomposisi, dan Pelepasan Hara Serasah pada Tegakan Jabon (Anthocephalus cadamba Miq.).
Abstrak: Maintaining the nutrient supply in soil is crucial for sustaining productivity. Nutrient cycling in ecosystem provide available nutrient through inputs, storage pools, and outputs. In nutrient cycle, plant nutrient uptake from soil and return to soil from litterfall, coverground species, and remain harvest plant through decomposition process. Jabon putih (Anthocephalus cadamba Miq.) is one of Indonesia native species which has high prospect for plantation forest and revegetation in degraded ecosystem, such caused by mining operations. The soil of overburden dumps in coal mining are physically, nutritionally and biologically poor. This study was conducted to calculate productivity, decomposition rate, nutrient content and nutrient release to 4-year-old jabon plantation, also to test the application of jabon compost that applied to jabon seedling with soil from coal mine as planting media. Research was conducted at 4-year-old jabon plantation. Method of Litterfall productivity use litterfall collection traps every week during 12 weeks. Decomposition rate was used litter bag technique, with 120 of bags which placed above soil floor. Collecting data for use application of jabon compost was held during10 weeks. Total productivity during 12-week is 22.25 g m-2 week-1 or 11.57 ton ha-1 yr-1. Rate decay constant (k) is 0.09 week-1 and relative decomposition rate was 0.086 g g-1 week-1. Nutrient input from leaf litter, from highest to lowest, in the following order: Ca (238 kg ha-1 )> N (230 kg ha-1)> Mg (151 kg ha-1)> K (110 kg ha-1)> P (44 kg ha-1). Magnesium has the highest percentage of nutrient release that is 98.11 % during 12-week decomposition. Application of jabon compost to soil from coal mine has significant effects on height and diameter growth, total biomass, and shoot and root biomass, but it did not significantly effected on shoot-root ratio. Combination between media and 30 % jabon compost increased plant height by 69 %, diameter by 72 %, and biomass total by 193 % compared with control treatment.
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Judul: iRespon Pertumbuhan Tanaman Jabon (Anthocephalus cadamba (Roxb.) Miq.) Terhadap Pengapuran di Areal Bekas Tambang
Abstrak: The main problem of reclamation activities in the postmining land was marginal land that could not support the growth of plants, due to pH and the low level of nutrient. So that, the selection of local species which adaptable and the appropriate silviculture treatment was needed. Jabon (A. cadamba) is one of local tree species that had high prospect, because jabon classified into fast growing species, able to adapted various site conditions, and the silviculture treatment was relatively easy. Dolomit and gypsum were materials that contained of Ca (Calcium), which able being applied to increase the soil pH. This objectives research was to determine the effect of dolomit, crude gypsum and manure fertilizer on the growth of Jabon in postmining land at PT. Tunas Inti Abadi. The fertilizers treatment consisted of three treatments. There were 2 kg of manure fertilizer (N), 2 kg of manure fertilizer + 200 g of dolomit (KN), and 2 kg of manure fertilizer + gipsum 200 g (GN). The parameters that be measured were diameter, height, crown diameter, percentage of living. The combination of dolomit and manure fertilizear had significant effect on the 95% confidence interval the diameter of Jabon.
Keyword: reclamation, calcification, fertilizer, jabon

Judul: Kajian frieze groups untuk klasifikasi dan konstruksi desain berdasarkan simetri pada pola
Abstrak: Frieze groups adalah konsep matematika untuk mengklasifikasikan desain pada dua dimensi permukaan yang berulang-ulang dalam satu arah berdasarkan simetri pada pola. Frieze groups merupakan grup yang mempertahankan bentuk pola. Pergerakan bentuk pola terdiri dari translasi, refleksi dan rotasi 180o. Tujuan dari karya ilmiah ini adalah mengkaji sifat Frieze group, mengkaji penggunaan Frieze group dalam mengklasifikasikan simetri pada pola dan mengkonstruksi pola dengan menggunakan software tesselmania. Hasil yang telah diperoleh, bahwa jenis Frieze groups merupakan subgroup dari grup pergerakan pola. Selain itu dapat dilihat dari sifat isomorfik berbagai jenis Frieze groups. Untuk mengkonstruksi sebuah bentuk pola dapat menggunakan salah satu software untuk membentuk sebuah pola bidang datar (dua dimensi) yaitu tesselmania.
Keyword: Frieze groups, Simetri, Pola