Judul: Pengaruh Pupuk Organik Hayati Terhadap Pertumbuhan Garut dalam Sistem Agroforestri Sengon Lokal
Abstrak: Alih fungsi lahan hutan menjadi lahan pertanian semakin meningkat seiring dengan tingginya pertambahan jumlah penduduk. Pemanfaatan lahan hutan dapat tetap berjalan secara optimal dengan menerapkan sistem agroforestri. Tegakan sengon lokal dengan tutupan tajuk ringan dapat dikombinasikan dengan garut karena jenis ini dapat beradaptasi di bawah naungan. Tujuan penelitian ini adalah mengetahui pertumbuhan tegakan sengon dan menganalisis pengaruh sistem penanaman dan dosis pupuk organik hayati terhadap pertumbuhan garut. Tahapan dalam penelitian ini meliputi penyiapan media tanam dan bibit/anakan garut, penanaman, aplikasi pemupukan, pemeliharaan garut, dan pemanenan garut. Sengon berumur 3 tahun menghasilkan riap tinggi 1,30 m dan riap diameter 0,50 cm selama 5 bulan dengan rata-rata tinggi 23,16 m dan rata-rata diameter 13,95 cm. Produktivitas umbi pada sistem monokultur menghasilkan 7,70 ton/ha, sedangkan pada sistem agroforestri 6,01 ton/ha. Pemberian pupuk organik hayati dosis 15 mL menghasilkan pertumbuhan tertinggi pada sistem agroforestri dan dosis 25 mL menghasilkan pertumbuhan tertinggi pada sistem monokultur., The conversion of forest land into agricultural land is increasing along with the high population growth. The utilization of forest land can continue to run optimally by implementing an agroforestry system. Stands of local sengon with light canopy cover can be combined with arrowroot because this species can adapt under shade. The purpose of this study was to determine the growth of local sengon stands and to analyze the effect of the planting system and dose of biological organic fertilizer on arrowroot growth and productivity. The research procedures include the preparation of planting media and arrowroot seedlings, planting, application of biofertilizer, arrowroot maintenance, as well as harvesting. Three years old sengon yielded increments of 1.30 m in height and 0.50 cm in diameter during 5 months with an average height of 23.16 m and an average diameter of 13.95 cm. The productivity of tubers in the monoculture system was 7.70 tons/ha, while in the agroforestry system was 6.01 tons/ha. The application of biological organic fertilizer at a dose of 15 mL yielded the highest growth on the agroforestry system and a dose of 25 mL yielded the highest growth on the monoculture system.
Keyword: shade, productivity, agriculture, high increment, plants functional food

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.
Keyword: