Judul: Pengaruh Pemberian Takaran Pupuk Amonium Sulfat terhadap Pertumbuhan, Produksi, Kadar dan Serapan Hara Tanaman Jagung (Zea mays L.) Pada Latosol Dramaga, Bogor
Abstrak: Maize (Zea mays L.) is one of food commodities and alternative forage that has been cultivated in Indonesia for a long time. The potential for post-harvest processing and food diversification encourage further development of maize cultivation. The aim of this study was to determine the effective doses of nitrogen fertilizer (ZA) application for growth, production, plant nutrients concentration and nutrient uptake of maize. The study was conducted in an experiment field using a Randomized Block Design, with eight treatments that were unfertilizer plot (Control), ZA-Standard, Urea-Standard and ZA-Tests in different doses of awarding (0.25 ZA, 0.50 ZA, 1.00 ZA, 1.50 ZA, 2.00 ZA). Each treatment was performed in three replications. Results showed that the highest growth of plant, maize production, N plant concentration and N uptake were achieved in treatment of 1.00 ZA, although it was not statistically different compared with the other treatments, except Control (unfertilizer plot) and 0.25 ZA treatment. The highest percentage of RAE (Relative Agronomic Effectiveness) was achieved by 1.00 ZA treatment, and its RAE value was increased up to 35.03% than ZA Standard.
Keyword: Bogor Agricultural University (IPB), production, plant nutrients concetration, maize, growth, ammonium sulfate

Judul: Effect of NPK Compound Fertilizer on growth, Yield and Nutrient Uptake of Maize (Zea Mays. L) In Darmaga’s Latosol
Abstrak: Saat ini aktivitas pertanian sangat tergantung pada pupuk dan pemupukan khususnya pada 20 tahun terakhir. Hal ini disebabkan tanah-tanah pertanian di Indonesia memiliki tingkat kesuburan tanah relatif rendah sehingga kurang mampu mendukung pertumbuhan tanaman. Pemupukan merupakan cara terpenting dalam mendorong pertumbuhan tanaman yang lebih baik. Penelitian ini bertujuan membandingkan pengaruh pemberian pupuk majemuk dan pupuk konvensional terhadap pertumbuhan, produksi, dan serapan hara tanaman jagung pada Latosol Darmaga. Pupuk majemuk bermerk “Big Growth” (15:15:10) (yang selanjutnya disingkat BG) dibandingkan dengan pupuk konvensional yaitu Urea, SP 36 Dan KCl. Percobaan dilakukan di kebun percobaan Cikabayan, Darmaga, Bogor. Analisis tanah dan jaringan tanaman dilakukan di Laboratorium Kimia dan Kesuburan Tanah, Departemen Ilmu Tanah dan Sumberdaya Lahan, Fakultas Pertanian, Institut Pertanian Bogor. Rancangan Kelompok Lengkap Teracak (RAK) dengan 6 perlakuan dan 3 ulangan diterapkan pada percobaan ini. Perlakuan yang diberiakan adalah: (1) Kontrol (2) Standar (3) BG 0.5 (4) BG 1.0 (5) BG 1.5 (6) BG 2.0 yang masing-masing setara dengan 0.5; 1; 1.5; dan 2 kali dosis standar. Hasil percobaan menunjukan bahwa perlakuan Standar dan BG nyata meningkatkan tinggi tanaman, bobot tongkol per petak, bobot tongkol contoh dan bobot pipilan jagung per petak dibandingkan perlakuan Kontrol. Perlakuan BG mempunyai pengaruh yang tidak berbeda nyata pada serapan hara N dan K dibandingkan standar. Bobot tongkol per petak pada perlakuan BG 0.5 relatif sama dengan Standar namun untuk bobot pipilan per petak cenderung lebih tinggi dari Standar meskipun secara statistik tidak berbeda nyata. Disamping hal tersebut perlakuan BG menimbulkan pengaruh residu pada kadar P tersedia dan K dapat ditukar yang cenderung meningkat setelah percobaan.
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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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