Judul: Keanekaragaman Jenis Tumbuhan pada Tanah Ultrabasa di Areal Konsesi PT. INCO Tbk. Sebelum Penambangan Propinsi Sulawesi Selatan
Abstrak: Ultrabasic soils have considerable amount of heavy metal content and cause the existing vegetation to have very unique properties. Soils which develop in ultrabasic soils are very poor due to high content of Fe, Mg, Al and Ni. Ultrabasic soils occupy two altitudinal zonations, namely lowland mafic zone 􀀋􀂔1000 m asl) and upland mafic zone (􀂕 1000 m asl). Areas of ultrabasic soils in this Verbeek mountain range constitutes the concession area of PT INCO Tbk, which in the future will be mined, and therefore there is a need for a study concerning its species diversity. The objective of this study was studying plant species diversity existing in the ultrabasic soils. This research was conducted by vegetation analysis method for vegetation stages of seedlings, saplings, poles, trees, and non tree vegetation. Placements of sample plots was conducted by purposive sampling in each zonation (lowland mafic and upland mafic zones) with size of 20 m X 500 m (1 ha), and for each zone there were two sample plots. Therefore, the total area size of the research sample plots was four hectares. Research results showed that the number of species found in lowland mafic plot (LLM) for tree stage was 61 species, whereas that in upland mafic (ULM) was 19 species. Status of species diversity (H􀂶) in tree stage in the research location was categorized as ranging from low to high. Value of H􀂶 for tree stage ranged between 2.06 􀂱 3.13, value of species richness (R) were 5.96 􀂱 8.53, and value of species evenness (E) were 0.73 􀂱 0.86. Dominant species at tree stage and regeneration in nearly all sample plots was species of Heritiera trifoliata. Other dominant species were Gironniera subequalis, Sloetia elongate and Acmena acuminatissima. Those of local endemic species found in this study were among other things Kjelbergiodendron celebica, Hopea celebica, Lithocarpus celebica, Calophyllum celebicum, Diospyros celebica, Agathis celebica, Garcinia celebica, Metrosideros vera and Sarcotheca celebica. Number of trees in diameter class of 20 cm up was greater in ULM zone, as compared with that in LLM zone. On the other hand, basal area and volume of trees with diameter of 20 cm up was greater in LLM zone. Therefore, in LLM, number of trees was smaller, but the average tree size was greater as compared with that in ULM zone. Level of soil fertility in LLM plots were higher as compared with that in ULM plots. Values of pH in LLM plots were higher as compared with those in ULM plots, whereas contents of Fe, Ni and Al were higher in plots of ULM. Dominant species, such as Heritiera trifoliate , as well as those local tree species which had been mentioned above were tree species which had been adapted to the properties of ultrabasic soils. Therefore, those species need to be maintained in terms of their sustainability and cold be made as priority for rehabilitation of ex mining land in ultrabasic soils
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Judul: Analysis of soil Chemical and Biological Characteristics of Soil in Several Types Land Use in Sulawesi Tengah
Abstrak: Penggunaan lahan yang beragam serta pengelolaan yang intensif mengakibatkan penurunan tingkat kesuburan tanah di suatu lahan. Penggunaan lahan di Sulawesi Tengah banyak difungsikan sebagai perkebunan dan pertambangan sehingga populasi mikrob di setiap penggunaan lahannya berbeda-beda. Penelitian ini bertujuan mengetahui karakteristik sifat kimia dan sifat biologi tanah pada berbagai penggunaan lahan di Sulawesi Tengah. Pengambilan sampel tanah dilakukan dengan menggunakan metode purposive random sampling di Sulawesi Tengah. Lokasi penelitian yaitu Kecamatan Lore Utara dan Mantikulore (pertambangan emas), Kecamatan Nokilalaki (Kakao), dan Kecamatan Banawa Selatan (Kelapa Sawit). Hasil analisis menunjukkan populasi mikrob dan fungi tertinggi terdapat pada penggunaan Lahan Sawit yang memiliki kadar C-organik yang rendah dan kadar N-total yang sedang. Sedangkan populasi mikrob dan fungi terendah terdapat pada lahan Tambang Konvensional dengan kadar C-organik dan N-total yang rendah. Berdasarkan hasil analisis kimia tanah, Lahan Kakao memiliki kadar C-organik dan N-total lebih tinggi di antara penggunaan lahan lain, sedangkan kadar P dan K total t e r t i n g g i dimiliki oleh lahan Tambang Konvensional. Kadar C-organik dan nisbah C/N tanah berpengaruh terhadap tinggi rendahnya nilai respirasi yang dihasilka, Land use diversity and land management intensively have decreased soil fertility. One of the dominant land uses in Central Sulawesi are plantations and mining, which has an impact on the microorganism’s population. This study was aimed to determine the characteristics of chemical and biological properties of soil in various land uses in Central Sulawesi. Soil sampling was carried out using the purposive random sampling method in Central Sulawesi. The research location are North Lore District and Mantikulore District (Mining), Nokilalaki District (Cocoa), and South Banawa District (Oil Palm). The results showed that the highest concentrations of bacteria and fungi population was Oil Palm plantations which has low C-organic levels and moderate total N levels, the lowest bacterial and fungal populations was Conventional Mining with low levels of organic C and total N. Based on soil chemical properties, Cacao land has the highest content of C-organic and the total N, otherwise Conventional mining has the highest Phosphate and Potassium content. Meanwhile, C-organic and C/N ratio of soil have an effect to the high and low value of the soil respiration.
Keyword: Cocoa, C/N ratio, Gold mining, Oil Palm, Plantation

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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