Judul: Growth and Productivity of Sorghum First Ratoon Variety Samurai 1 with the Addition different of Urea Fertilizer and Harvest Ages
Abstrak: Penelitian ini bertujuan mengetahui pertumbuhan dan produktivitas tanaman sorgum manis ratun pertama varietas Samurai 1 dengan perlakuan pemberian dosis pupuk urea dan umur panen yang berbeda. Penelitian dilaksanakan di Unit Pendidikan Penelitian Peternakan (UP3J) Jonggol dan Laboratorium Agrostologi, Ilmu Gizi dan Teknologi Pakan Fakultas Peternakan Institut Pertanian Bogor selama 4 bulan. Rancangan percobaan yang digunakan adalah RAKF (Rancangan Acak Faktorial) dengan pola 3 x 3 dan empat kali ulangan. Penelitian ini terdiri dari 3 perlakuan pemupukan dan 3 perlakuan umur panen. Perlakuan tersebut adalah P1 (pemupukan N 100 kg ha-1), P2 (pemupukan N 200 kg ha-1), P3 (pemupukan N 300 kg ha-1), T1 (umur panen 60 hari), T2 (umur panen 65 hari), T3 (umur panen 65 hari). 70 hari). Data dianalisis dengan analisis varian (ANOVA), jika ada signifikansi dilanjutkan dengan uji Duncan. Peubah yang diamati adalah pertambahan tinggi, diameter, jumlah daun, jumlah anakan, biomassa, berat segar, berat kering, dan nilai brix. Hasil penelitian menunjukkan ada interaksi antara dosis pupuk urea dan umur panen terhadap berat segar total dan berat segar daun. Umur panen berpengaruh nyata terhadap tinggi tanaman, diameter jumlah daun, jumlah anakan, biomassa, berat segar, berat kering oven, dan nilai brix. Pemupukan tidak berpengaruh nyata, tetapi perlakuan pemupukan urea 200 kg ha-1 dan umur panen 70 hari pada sorgum ratun pertama Samurai 1 memiliki nilai tertinggi pada tinggi tanaman, diameter, jumlah daun, jumlah anakan berat kering oven daun, dan batang., This study aimed to evaluate the growth and productivity of the first ratoon sorghum Samurai 1 with the treatment of urea fertilizer doses and different harvest age. The research was conducted at the Jonggol Animal Research Education Unit (UP3J) and the Laboratory of Agrostology, Nutrition Science and Feed Technology, Faculty of Animal Science, Bogor Agricultural University for 4 months. The experimental design used was Factorial Randomized Design (FRD) with a 3 x 3 pattern and four replications. This study consisted of 3 treatments of fertilization and 3 treatments of harvest age. The treatments were P1 (fertilizing 100 kg N ha-1), P2 (fertilizing 200 kg N ha-1), P3 (fertilizing 300 kg N ha-1), T1(harvested at 60 days age), T2 (harvested at 65 days age), T3 (harvested at 70 days age). The data was analyzed by analysis of variance (ANOVA), and if there were any significances, it will be continued with Duncan test. The variables observed were increased in height, diameter, number of leaves, number of tillers, biomass, fresh weight, dry weight, and brix content. The results showed there was an interaction between urea fertilizer dose and harvest age on total fresh weight and leaf fresh weight. Harvest age had a significant effect on plant height, leaf diameter, number of tillers, biomass, fresh weight, oven dry weight, and brix content. Fertilization had no significant effect, but urea fertilization treatment of 200 kg ha-1 and harvest age of 70 days on the first ratoon sorghum Samurai 1 had the highest values on plant height, diameter, number of leaves, number of tillers, oven dry weight of leaves, and stems.
Keyword: growth, harvest age, productivity, sorghum, urea fertilizer

Judul: Growth and Production of Sorghum Plant Varieties F1 Samurai 1 in the Ratun 1 With Urea Level and Harvesting Age
Abstrak: Penelitian ini bertujuan mengkaji pengaruh dosis pupuk N dan umur panenterhadap pertumbuhan dan produksi biomassa sorgum Samurai 1. Penelitian inimenggunakan rancangan acak kelompok pola faktorial terdiri dari 3 taraf dosis pupuk urea yaitu P1 (100 kg urea/ha), P2 (200 kg urea/ha), dan P3 (300 kg urea/ha), serta 3 taraf umur panen yaitu T1 (60 hari setelah panen (HSP)), T2 (65 HSP), T3 (70 HSP) dengan setiap kombinasi perlakuan diulang 4 kali sebagai kelompok. Hasil penelitian menunjukkan bahwa pengaruh interaksi dosis pupuk urea dan umur panen terlihat pada parameter jumlah daun, berat kering total, berat kering batang dan berat kering malai per hektar dengan nilai tertinggi diperoleh dari kombinasi perlakuan dosis pupuk urea 200 kg urea/ha dan umur panen 70 HSP. Perlakuan dosis pupuk urea sebagai faktor tunggal tidak berpengaruh nyata pada parameter yang diamati. Sementara itu umur panen sebagai faktor tunggal berpengaruh nyata terhadap tinggi tanaman dan kadar brix dengan nilai tertinggi ditunjukkan oleh perlakuan umur panen 70 HSP. Kesimpulan dari hasil penelitian ini adalah sorgum Samurai 1 yang dipupuk 200 kg urea/hadan dipanen pada umur 70 HSP menghasilkan pertumbuhan dan produksi biomassa tertinggi., This research aimed to evaluate the effect of N fertilizer application and harvesting age on growth and biomass production of sorghum Samurai 1. This study use factorial block randomized design composing of 3 dose levels of urea fertilizer, namely P1 (100kg urea/ha), P2 (200 kg urea/ha), and P3 (300 kg urea /ha)), and 3 harvesting age level, namely T1 60 day after harvest (DAH), T2 65 DAH and T3 70 DAH with 4 group replications. The results showed that interaction between treatments of urea fertilizer dosage and harvesting age influenced (P>0.05) leave numbers, total dry weight, stem dry weight and panicle dry with the greatest value obtained from combination of 200 kg urea/ha and harvesting age of 70 DAH. Treatments of urea fertilizer dosage as a single factor had no significant effects on the observed parameters. Meanwhile, harvesting age as a single factor had significant effects on plant height and brix levels with the highest value indicated by the harvesting age treatment of 70 DAH. It is concluded that application of 200 kg urea/ha on sorghum Samurai 1 harvested at 70 DAH revealed the highest biomass production.
Keyword: growth, harvesting age, production, sorghum, urea fertilizer dosage

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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