Judul: Uji Penanaman Menggunakan Teknik Direct Seeding di Lahan Bekas Tambang Batu Kapur, Gunung Putri, Bogor
Abstrak: Kegiatan reklamasi dan rehabilitasi penting dilakukan untuk mengembalikan daya dukung lahan agar berfungsi kembali sesuai dengan peruntukannya. Inovasi dalam kegiatan reklamasi dan rehabilitasi lahan bekas tambang perlu dilakukan untuk mempercepat dan meningkatkan keberhasilan dalam mengembalikan fungsi lahan sesuai peruntukannya. Salah satu bentuk kegiatan reklamasi dan rehabilitasi lahan bekas tambang adalah revegetasi. Direct seeding adalah teknik penanaman dengan menggunakan benih yang ditanam langsung di lapangan tanpa melalui tahapan pembibitan di persemaian. Penting untuk menganalisis pertumbuhan tanaman yang ditanam menggunakan teknik direct seeding dan penanaman menggunakan semai. Kedua teknik tersebut diujicoba untuk merehabilitasi lahan bekas tambang batu kapur PT. Solusi Bangun Indonesia di Bogor. Benih dan bibit yang digunakan dalam penelitian ini adalah merbau (Intsia bijuga), ketapang (Terminalia catappa), jengkol (Archidendron jiringa), bisbul (Diospyros blancoi), dan nangka (Artocarpus heterophyllus). Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap (RAL) dengan kombinasi metode penanaman dan pemupukan serta lima jenis tanaman sebagai perlakuan. Benih dan bibit kelima tanaman tersebut ditanam di lahan bekas tambang batu kapur dengan kondisi tanah yang didominasi fraksi pasir. Hasil penelitian menunjukkan bahwa tanaman yang ditanam dengan teknik direct seeding memiliki persentase bertahan hidup dan rata- rata pertumbuhan tanaman yang sama bahkan cenderung lebih baik dibandingkan dengan tanaman yang ditanam menggunakan bibit polybag. Jenis tanaman yang dapat ditanam menggunakan teknik direct seeding di lahan terbuka bekas tambang batu kapur adalah nangka dan merbau, sedangkan jengkol kurang mampu bertahan pada kondisi lingkungan yang kering, ketapang yang ditanam menggunakan teknik direct seeding rentan terhadap serangan hama yang menyebabkan benih gagal berkecambah, dan bisbul yang memiliki pertumbuhan kurang baik walaupun persentase hidup dan daya berkecambahnya tinggi. Penanaman menggunakan teknik direct seeding mampu menghemat biaya penanaman dibandingkan menggunakan bibit tanaman hingga 65%. Berdasarkan uraian diatas dapat disimpulkan bahwa teknik direct seeding menggunakan jenis nangka dan merbau dapat dilakukan untuk mempercepat reklamasi dan rehabilitasi lahan bekas tambang batu kapur dan menghemat biaya operasional penanaman., Reclamation and rehabilitation activities are carried out to restore the land function according to its designation. Innovations in reclamation and rehabilitation of ex-mining land need to be carried out to accelerate and increase success in restoring land functions. One form of reclamation and rehabilitation of ex-mining land is revegetation. The direct seeding technique is a planting method using seeds planted directly in the field without going through nursery stages. It is important to analyze and find out wether the direct seeding technique has better plant growth when compared to planting using seedlings. The technique was tested to rehabilitate ex-limestone mining of PT. Solusi Bangun Indonesia in Bogor. The seeds and seedlings used in this study were Merbau (Intsia bijuga), ketapang (Terminalia catappa), jengkol (Archidendron jiringa), bisbul (Diospyros blancoi), and jackfruit (Artocarpus heterophyllus). This experiment design used was a completely randomized design (CRD) with combination of planting methods and fertilizer as well as five tree species as treatments. The seeds and seedlings are planted on ex-limestone mining land which has soil with a dominant sand fraction. The results showed that plants grown using the direct seeding technique had a higher survival rate than seedlings, except for ketapang. The growth of plants grown using the direct
Keyword: Direct seeding, Ex-limestone mining land, Reclamation, Seedlings

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: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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