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: The Effect of ZA Fertilizer on the Growth and Yield Component of Sweet Corn (Zea mays saccharata)
Abstrak: Pupuk Amonium sulfat (ZA) memiliki kandungan utama nitrogen (21%) dan sulfur (24%). Penelitian ini bertujuan untuk mempelajari pengaruh dosis pupuk ZA terhadap pertumbuhan dan komponen hasil jagung manis. Penelitian dilaksanakan pada bulan Januari hingga April 2023 di kebun Sabisa Farm IPB, Sindangbarang, Kota Bogor. Rancangan percobaan yang digunakan adalah rancangan kelompok lengkap teracak (RKLT) faktor tunggal. Perlakuan dosis pupuk terdiri dari 6 taraf, yaitu (P0) tanpa pemberian pupuk nitrogen (Kontrol), P1 (NPK standar), P2 (337,5 kg ZA), P3 (506,3 kg ZA), P4 (675 kg ZA), dan P5 (1.012,5 kg ZA). Perlakuan diulang sebanyak 4 kali, sehingga terdapat 24 satuan percobaan (petak). Hasil penelitian menunjukkan bahwa perlakuan dosis pupuk ZA pada jagung manis berpengaruh nyata terhadap pertumbuhan fase vegetatif, fase generatif, hasil panen, dan peubah hasil. Pupuk ZA dinilai efektif terhadap pertumbuhan dan produksi jagung manis dengan nilai Relative Agronomic Effectiveness (RAE) diatas 95% pada perlakuan ZA 675 kg dan ZA 1.012,5 kg. Kata kunci: dosis pupuk, nitrogen, produksi, RAE, Increasing sweet corn production must be supported by optimal cultivation, one of which was the provision of the right dose of nitrogen fertilizer. Ammonium sulfate (ZA) fertilizer has the main content of nitrogen (21%) and sulfur (24%). This study aimed to study the effect of ZA fertilizer dose on growth and yield component on sweet corn. The research was conducted from January to April 2023 at the Sabisa Farm IPB recearch garden, Sindangbara, Bogor City. The experimental design used was a single-factor randomized complete block design (RCBD). The fertilizer dose treatment consisted of 6 levels, namely (P0) without nitrogen fertilizer (Control), P1 (standard NPK), P2 (337.5 kg ZA), P3 (506.3 kg ZA), P4 (675 kg ZA), and P5 (1,012.5 kg ZA). The treatment was repeated 4 times, so there were 24 experimental units (plots). The results showed that the dose treatment of ZA fertilizer in sweet corn had a significant effect on the growth of the vegetative phase, generative phase, yield component, and yield characters. ZA fertilizer is considered effective for the growth and production of sweet corn with a Relative Agronomic Effectiveness (RAE) value above 95% in ZA 675 kg and ZA 1,012.5 kg treatments. Keywords: fertilizer dosage, nitrogen, production, RAE
Keyword: fertilizer dosage, nitrogen, production, RAE

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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