Judul: Pengaruh Pupuk Organik dan Anorganik pada Tanaman Garut (Marantha arudinaceae L.) di bawah Tegakan Sengon (Falcataria moluccana Miq.)
Abstrak: Increased population is one of the factor that increase the land conversion rate, both in forest and agriculture land. Agroforestry systems can be a solution for increased need of agricultural land. Agroforestry combine forest stand with agricultural plant. Kind of the forest stand that start to be cultivated was sengon stand combined with agricultural plant was arrowroot (M. arudinaceae). Production of arrowroot can be improved by anorganic or organic fertilizers. The objective of this research is to observe growth of arrowroot plant under the stand of sengon, to observe the influence from type and dose of fertilizer, and to determine the best dose for each type of fertilizer which influence plant to produce the best arrowroot. The parameters observed from arrowroot plant are percent survival, height, leaf width, leaf length, number of leaves, number of roots and roots weight. The organic fertilizer gave significantly effect to height and number of leaves on the dose of fertilizer 1 400 mL/ha. While the anorganic fertilizer gave significant effect to height, number of leaves, and roots weight on the dose of fertilizer 60 kg/ha.
Keyword: sengon, organic fertilize, arrowroot, anorganic fertilize, agroforestry

Judul: Growth of Arrowroot (Maranta arundinacea) with The Combination of Organic Fertilizers in the Sengon Solomon Agroforestry System (Falcataria moluccana)
Abstrak: Garut (Maranta arundinacea) adalah tanaman tropis sumber pangan potensial. Sengon (Falcataria moluccana) adalah jenis pionir cepat tumbuh dari fabaceae. Garut berpotensi untuk dikombinasikan dengan sengon dalam agroforestri. Penelitian ini bertujuan menganalisis pertumbuhan sengon dalam sistem agroforestri serta pertumbuhan garut dengan pemberian kombinasi pupuk kandang kambing dan pupuk organik hayati (POH). Analisis sidik ragam menggunakan tingkat kepercayaan 95% dan uji lanjut Duncan. Kombinasi pupuk kandang kambing dan POH dalam sistem agroforestri tidak berpengaruh nyata pada seluruh parameter garut kecuali parameter jumlah daun. Pupuk kandang kambing 150 g dan POH 15 mL memberikan pertumbuhan lebih baik pada parameter garut tinggi dan jumlah daun. Pupuk kandang kambing 250 g dan POH 25 mL berpengaruh lebih baik pada parameter jumlah daun, jumlah anakan, berat kering total dan produktivitas umbi. Sengon solomon F1 umur 3 tahun mengalami peningkatan tinggi 0,7 m dan peningkatan diameter 0,78 cm, namun luas tajuk menurun sebesar 1,7 m2. Penurunan luas tajuk diduga oleh angin kencang dan hujan deras, sehingga cabang sengon bergesekan dan patah., Arrowroot (Maranta arundinacea) is tropical potential food plant source. Sengon (Falcataria moluccana) is fast-growing and pioneer species of fabaceae. Garut has the potential to be combined with sengon in agroforestry. This study aims to analyze the growth of sengon in agroforestry systems and the growth of arrowroot with combination of goat manure and bio-organic fertilizer (BOF). Analysis of variance using 95% confidence level and Duncan's test. The combination of goat manure and BOF in agroforestry system had no significant effect on all parameters of arrowroot, except the number of leaves. Goat manure 150 g and BOF 15 mL show better growth in the parameters of arrowroot height and number of leaves. Goat manure 250 g and BOF 25 mL had a better effect on the parameters of the number of leaves, the number of saplings, the total dry weight and the tubers productivity. Sengon solomon F1 age 3 years has increased the height of 0.7 m and increase in diameter of 0.78 cm, but the crown area decreased by 1.7 m². Decrease of sengon crown area is suspected by strong winds and heavy rains, so the sengon branches rub and break.
Keyword: agroforestry, arrowroot, bio-organic fertilizer, manure, sengon Solomon

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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