Judul: Karakteristik Gambut Pedalaman, Transisi dan Pantai di Provinsi Riau: Keterkaitan Tingkat Dekomposisi dan Sifat Kimia Gambut dengan Produktivitas Biomassa Kelapa Sawit
Abstrak: Increased demand for palm oil derivative products (CPO, crude palm oil) causes the ever faster rate of and widespread land clearing for oil palm plantation area. Land clearing for this purpose is generally perfomed on peat swamps. In Riau Province, until year 2007, the use of peatlands for cultivating various plantation crop commodities have reached ±817.593 ha. Since peatlands are considered vulnerable to land clearing, this activity and its subsequent land management should be based on the nature and characteristics of the peat material which is largely determined by its formation physiography. Based on this background, this study aims to assess the relationship between the degree of decomposition and chemical properties of peatlands developed on fresh-water, brackish and marine physiography with biomass productivity of cultivated oil palm with age of <6 and >6 years in Riau Province. Field observations and sampling of the peat materials were conducted in January 2010. The results showed that the peat materials of Riau that developed on freshwater, brackish and marine physiography were at hemic decomposition degree. Based on the relationship between the degree of decomposition and the value of E400/E600 ratio, peat materials of the fresh-water, brackish and marine physiography cultivated for oil palm with age of >6 years were dominated by oldhemic decomposition degree (E400/E600 <5,0). Whilst, it was found in the brackish physiography with oil palm of age of <6 years peat materials with hemic decomposition degree (E400/E600 >5,0). This suggests that the degree of humification of the peat materials on oil palm cultivating lands with age of <6 years were lower than those with age of >6 years. The average organic-C content of the inland and transition peatlands were higher than those of the coastal one. The acidity was in moderate to high level in which the higher average values of pH-H2O and pH-KCl were found in transition and coastal peatlands. The average concentration of total N, P2O5 and K2O were also higher in the transition and coastal peatlands. The highest total biomass productivity of oil palm was found in the transition peatlands, both at the age of <6 and >6 years. The results of this study provides additional scientific facts that as compared to the coastal and inland ones, the transition peatlands provide as the best medium for the cultivation of oil palm, especially in Riau Province.
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Judul: The Character of enzyme in oil palm rhizosphere on peatland
Abstrak: Pemanfaatan lahan gambut menjadi perkebunan kelapa sawit saat ini menjadi sorotan karena dikaitkan dengan emisi CO2 dari dekomposisi gambut. Dekomposisi gambut dipercepat sebagai akibat drainase lahan gambut untuk menciptakan kondisi lingkungan yang sesuai bagi perkembangan dan pertumbuhan kelapa sawit. Perubahan lingkungan gambut di rizosfer kelapa sawit seperti komposisi lignoselulosa, status hara total, asam organik eksudat akar menentukan karakter enzim sebagai indikator dekomposisi gambut. Karakter enzim yang terukur sebagai aktivitas enzim menjadi informasi dasar untuk mendukung pengelolaan dan stabilitas gambut di perkebunan kelapa sawit. Penelitian ini disusun dengan tujuan melakukan pengkajian terhadap: 1) perubahan komposisi lignoselulosa sebagai penyusun gambut, 2) status hara gambut sebagai penentu aktivitas enzim dirizosfer, 3) kontribusi perakaran di lahan gambut dalam proses dekomposisi bahan gambut, 4) aktivitas enzim sebagai indikator proses dekomposisi di rizosfer pada lahan gambut Pengamatan dilakukan pada 3 jenis penggunaan lahan (kebun kelapa sawit, hutan dan semak). Pengamatan dan pengambilan sampel gambut dilakukan dengan metoda transek yaitu terdapat 8 transel<: pada ketiga penggunaan lahan. Pada kebun kelapa sawit transek mewakili 2 ketebalan gambut yaitu <3m dan > 3 m dan dari dua kelompok ketebalan gambut tersebut dipilih lokasi yang memenuhi kriteria umur kelapa sawit yaitu <6, 6-15, > 15 tahun. Transek ditetapkan tegak lurus dengan saluran drainase (collection drain). Sampel gambut yang diambil adalah gambut yang menempel pada akar. Bahan gambut dikomposit pada kedalaman lapisan perakaran 0-25, 25-50, 50-75cm tergantung tinggi muka air tanah dan pada jarak 0-1, 1-2, 2-3, 3-4m dari pohon pada seperempat lingkaran tajuk pohon, hal ini dilakukan mengingat adanya perbedaan distribusi perakaran kelapa sawit dari pangkal pohon kelapa sawit dan adanya aplikasi pupuk pada piringan kelapa sawit yaitu pada jarak l-2m dari pohon. Informasi karakter enzim di rizosfer kelapa sawit pada lahan gambut dihubungkan dengan komposisi lignoselulosa (kadar selulosa, hemiselulosa dan lignin), status hara total (N, P, K, Ca, Mg, Fe, Cu, dan Zn), distribusi bobot akar, eksudat akar (kadar asam organik karboksilat dan fenolat), dan aktivitas enzim terkait pemupukan yaitu urease, fosfatase, serta terkait dekomposisi gambut yaitu Pglukosidase dan laccase., The extension of oil palm plantation in peatland has been a controversial due to CO2 emmision from peat decomposition. Peat decomposition could be caused by peatland drainage to improved peat environment for supporting roots growth and development. Changes of peat environtment in oil palms rhizosphere like composition of lignocellulose, state of nuti;ients, organic acids exudate could influenced the character of enzyme, which was measured by enzyme activities. Enzyme activity could be as peat decomposition. Some research had been showed that fertilizer application triggered peat decomposition. Enzyme activities might be a basic information to support stability and management of peatland in oil palm plantation. This research was arranged to studied : 1) the change of lignocelluloses composition of peatmatter, 2) the total nutrients state in oil palm rhizosphere, 3) the contribution of oil palm roots in peat land as producer of root exudate, 4) enzyme activities as decomposition processes indicators in the rhizosphere of peatland. The research site in oil palm plantation was involved 3 landuse for location observation (oil palm plantation, degraded forest, and shrubs). The observation and peat sampling were
Keyword: lignocellulose composition, total nutrients, organic acids exudate, enzyme activities, peat matter in rhizosphere, Peat Decomposition, Oil Palm Plantation

Judul: Analisis kestabilan model infeksi virus leukemia feline
Abstrak: Virus leukemia foline adalah virus penyebab kanker darah dan kerusakan swnsum tulang pada kucing. Virus ini menyebar secara pidemi melalui air liur dan lendir hidung lewat interaksi antarkucing. Penyebaran virus leukemia feline ini digarnbarkan dengan suatu model matematis yang memuat sejumlah persarnaan diferensial biasa non linear yang didasarkan pada prinsip-prinsip epidemi standar (Murray, 1989). Model ini mendeskripsikan penyebaran virus lellkelllia feline dalarn suatu populasi konstan yang dihubungkan dengan waktu.
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