Judul: Pemanfaatan Arang Sekam untuk Memperbaiki Pertumbuhan Semai Jabon (Anthocephalus cadamba (Roxb.) Miq) pada Media Subsoil
Abstrak: Pemanfaatan arang telah meluas dalam bidang pertanian dan kehutanan terutama pada pembibitan. Arang tidak hanya digunakan sebagai sumber energi bahan bakar tetapi juga dapat dijadikan bahan pembenah tanah (perbaikan sifat-sifat tanah) dalam upaya memperbaiki pertumbuhan tanaman dan rehabilitasi lahan. Jenis yang digunakan dalam penelitian ini adalah jabon (Anthocephalus cadamba (Roxb.) Miq). Jabon merupakan salah satu jenis yang memiliki prospek bagus untuk dikembangkan dalam pembangunan hutan tanaman (HTI dan Hutan Rakyat). Tujuan penelitian ini adalah untuk mengetahui pengaruh penambahan arang sekam terhadap pertumbuhan semai jabon di media subsoil. Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap (RAL) satu faktorial terdiri dari 5 perlakuan yaitu penambahan arang sekam pada media subsoil sebanyak 0% (kontrol), 2,5%, 5%, 7,5% dan 10% (v/v) dengan 10 kali ulangan, tiap ulangan terdiri dari 3 semai. Banyaknya media (subsoil) yang digunakan adalah 2/3 volume polybag berukuran 10 x 15 cm. Hasil pengamatan menunjukkan bahwa penambahan arang sekam pada media subsoil dapat meningkatkan secara nyata tinggi dan berat kering total (biomassa) semai jabon jika dibandingkan dengan kontrol. Penambahan arang sekam sebanyak 5% (v/v) pada subsoil menghasilkan pertumbuhan semai jabon terbaik dengan peningkatan tinggi sebesar 27,42% dan 65,64% untuk berat kering total (biomassa). Semai pada media tanpa arang sekam (kontrol) memiliki pertumbuhan paling lambat dibanding semai jabon di media yang ditambahkan arang sekam. Penambahan arang melebihi dosis 5% (v/v) hanya memberikan sedikit efek pada pertumbuhan semai jabon (A. cadamba).
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Judul: Pertumbuhan Semai Jabon (Anthocephalus cadamba Roxb Miq) Pada Media Pasca Penambangan Batubara Yang Diperkaya Fungi Mikoriza Arbuskula, Limbah Batubara dan Pupuk NPK
Abstrak: One of the problems created by coal mining activities is the progressive increase of critical land area size and environmental damage, which are among other things in the form of worsening physical, chemical and biological properties of soils which lead to decrease of soil fertility and disturbed plant growth. Growth and nutrient absorption by Jabon seedlings have been studied in terms of their respond toward application of Arbuscular Mycorrhizal Fungi (AMF), coal waste, and soil media being used after coal mining operation. The experiment was designed as factorial completely randomized design, comprising 3 treatment factors, namely, species of AMF inoculants (control, Glomus sp., and Gigaspora sp.), growth media (control, mixture of 15% south Kalimantan coal, and mixture of 15 % Jambi coal) and concentration of NPK fertilizer (control, 2 gram/polybag, and 4 gram/polybag) with 10 replications, so that in total, there were 270 experimental units. Results showed that interaction between AMF, growth media and fertilizer had significant effects on parameters of diameter increment, shoot biomass, root biomass, total dry weight, index of planting stock quality, and percent of AMF colonization. Parameter of height increment and number of Jabon seedling leaves were affected by interaction between AMF and fertilizer. Treatment combination of AMF inoculants, coal powder, and NPK fertilizer was able to increase the concentration and absorption of nutrients N, P and K. The three treatments combination showed positive correlation between increase in concentration of nutrients N, P and K; and shoot biomass of Jabon seedlings.
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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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