Judul: Pengaruh Pemupukan Kalium terhadap Pertumbuhan dan Produksi Beberapa Varietas Kedelai Hitam (Glycine soja) pada Budidaya Jenuh Air di Lahan Pasang Surut
Abstrak: Saturated soil culture can prevent oxidation of pyrite from negative influences and it can to improve the productivity of soybean. The objective of this experiment was to study the effect of potassium fertilization on the growth and production of Ceneng, Cikuray, Lokal Malang, and Tanggamus under saturated soil culture on tidal swamp. The experiment was conducted at Banyu Urip, Tanjung Lago, Banyuasin, West Sumatera, from May until September 2013. The experiment used split plot design with 3 replications. The main plot was is variety consisted of Ceneng, Cikuray, Lokal Malang, and Tanggamus. The sub plot was is potassium fertilization consisted of 0, 30, 60 and 90 kg K2O ha-1. The experiment results show that kalium fertilization increased yield of black soybean. Productivity was affected by single factors that is variety and potassium fertilization. The interaction between variety and potassium fertilization did not effect to the all variables. The highest productivity of black soybean was obtained from Ceneng variety, 3.58 ton ha-1. The potasium fertilization 90 kg ha-1 gave the highest productivity as such as 3.72 ton ha
Keyword: saturated soil culture, potassium, Lokal Malang, Cikuray, Ceneng

Judul: Pengaruh Pemberian Abu Sekam, P, dan K terhadap Pertumbuhan dan Produksi Kedelai Hitam pada Budi Daya Jenuh Air di Lahan Pasang Surut
Abstrak: The experiment was carried out to evaluate the effect of husk ash, phosphorus, and potassium fertilizer on the growth and production of black soybean under saturated soil culture on tidal swamps. The experiment was conducted in the tidal swamps of South Sumatera Province, Banyu Urip village, sub District of Tanjung Lago, Banyuasin District, Palembang since April to August 2014. This experiment was using Randomize Complete Block Design with three replications. The concentration of husk ash as the first factor consist of 0, 1 000, 2 000, 3 000 kg ha-1, the concentration of phosphorus fertilizer as the second factor consist of 36 and 72 kg ha-1 P2O5, and the concentration of potassium fertilizer as the third factor consist of 30 and 60 kg ha-1 K2O. Saturated soil culture (SSC) technique was used to support the cultivation of soybeans in tidal swamps. The results showed that the effect of husk ash concentration, interactions of husk ash and phosphorus fertilization, interaction of husk ash and potassium fertilization and interaction of husk ash, phosphorus and potassium fertilization increased the ammount of trifoliat leaves. The optimum combination of 1.26 ton ha-1 husk ash, 36 kg ha-1 P2O5 phosphorus fertilization and 30 kg ha- 1K2O potassium fertilization gave the highest productivity by 4.21 ton ha-1and decreased the dose of Phosphorus and Potassium fertilizer
Keyword: Bogor Agricultural University (IPB), under saturated soil culture, potassium, phosphorus, husk ash, black soybean

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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