Judul: Pengembangan teknik pembenihan langsung (Direct seeding) untuk regenerasi hutan
Abstrak: Reforestasi lahan di-wilayah tropika umumnya dilakukan dengan penanaman dengan bibif namun dalam prakteknya memiliki kekurangan diantxanya membutuhkan biaya yang cukup besar. Oleh karena itu, teknik pembenihan langsung dapat dijadikan sebagai metode alternatif untuk tujuan yang sama Teknik pembenihau langsung telah dipraktekan untuk merehabilitasi lahan pasca tambang, rehabilitasi lahan dan hutan terdegradasi serta untuk sistem agroforesh-y. Penelitian ini bertujuan untuk mengetahui berbagai perlakuan metode penaburan (pembenaman) benih dan gulma terhadap pertumbuhan awal dan perkembangan tanaman, jenis tanaman yang wcok untuk diiembangkan dengan teknik pembenihan langsung serta efektivitas pembenihan langsung dari aspek teknis dan ekonomi. Penelitian ini dilaksanakan dengan tiga tahapan yakni pertama, seleksi jenis potensial untuk pembenihan langsung di rumah kaca Penelitian ini dilaksanakan di rumah kaca ~akult& Kehutanan IPB dengan menggunakan rancangan acak lengkap. kedua, pengujian mutu fisik dan fisologis benih dilakukan di rumah kaca kebun percobaan Cibayan dan Laboratorium Silvikultur Fakultas Kehutanan IPB pada bulan November sampai dengan Desember 2008 dan htiga, pengujian benih jenis terseleksi di lapangan di kebun percobaan Cikabayan pada Januari hingga April 2009.
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Judul: Pengembangan Penggunaan Metode Direct Seeding untuk Rehabilitasi Lahan Pasca Tambang PT Tunas Inti Abadi, Kalimantan Selatan
Abstrak: The method of direct seeding is developed in post mining land in order to give the opportunity to seeds to early adapt with extreem condition in post mining land. This method is implemented in impermanent reclamation land by small mining enterprises caused of its cheap operational cost. The objective of this research is to find out the efficiency of direct seeding method and the suitability of four species; trembesi (Samanea saman), sengon (Falcataria moluccana), sengon buto (Enterolobium cyclocarpum), and randu (Ceiba pentandra) in reclaiming post mining land. The research was conducted implementating three experiments: Experiment I implemented Seeds Physical and Physiological Quality Testing, Experiment II is Forest Species Seeds Adaptation in Post Mining Land, and Experiment III is Effect of Manure Addition in Seed Germination and Growth of Direct Seeding Results. Seed physical quality testing with 1000 grain weight method used the seeds which are classified into small size seeds (sengon and randu) and medium size seeds (trembesi and sengon buto). Based on physiological quality testing, the result of experiment I is 66.67% - 86.67%, Experiment II is 11.2% - 31.6%, and Experiment III is 7.2%-13.2%. Manure addition has significantly influenced the height and diameter growth in Experiment III, but not to the survival rate of plantation. In Experiment II, at the age of twelve weeks, the height of randu plantation was 9.6 cm; trembesi 7.9 cm; and sengon 3.6 cm. The diameter of sengon buto was 4.35 mm; randu 2.12 mm; trembesi 1.91 mm; and sengon 0.98 mm. The result of Experiment III is that average height of sengon buto was 41.5 cm; trembesi 15.4 cm; randu 12.4 cm; and sengon 7.4 cm. The diameter of sengon buto was 5.46 mm; trembesi 2.47 mm; randu 2.42 mm; and sengon 1.12 mm. The survival rate based on the plantation hole in Experiment II was the survival rate of randu and sengon was 66%; trembesi 58%; and sengon bruto 52%. In Experiment III, the higest survival rate was trembesi 72% followed by randu 40%, sengon 38% and sengon buto 28%. From the result of these four species used in the experiment, all of the species are highly adaptive with extreme condition in post mining land and suitable to implement with direct seeding method. It is also identified that size of seed highly influenced the successfulness of direct seeding. Small size seeds are the most suitable one in competition with weed. Direct seeding is more economic with plantation cost of 2 million rupiahs per hectare compared with conventional seeding method with cost of 4.487.500 rupiah per ha.
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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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