Judul: Optimalisasi Pertumbuhan dan Produktivitas Jarak Pagar (Jatropha curcas L.) Melalui Aplikasi Pemupukan.
Abstrak: The study was conducted to determine the effect of fertilizer application (dose and time) on the growth and productivity of jatropha. Research conducted at PT. Indocement, Citeureup, Bogor regency in October 2010 - July 2011. This research using randomized complete block design (RCBD) two factors. The first factor is the dose of fertilizer, which consists of five levels, namely 0, 24, 36, 48, and 60 g / plant. The second factor is the time of fertilization, namely 2 and 14 week after transplanting (WAT). Type of fertilizer used is NPK fertilizer, with a ratio of 15:15:15. Data obtained from observations processed using various analysis (ANOVA). Observations made in the vegetative phase of growth (plant height, leaf number, number of branches, and trunk diameter) and the generative phase (the number of productive branches, number of panicles, number of fruits, fruit weight, seed number and seed dry weight). Most of the dose of fertilization no significant effect on plant growth vegetative phase, except in the number of primary branches in 12 WAT. Significantly affect the dose of fertilization treatment increased the number of fruit and branches of productive. In general, from several observation variables (plant height, stem diameter, number of fruit, and productive branch) 48g/tanaman dose treatment tended to give better results. Fertilizer at 14 WAT is more effective, because it can have any number of fruit, fruit weight, seed number and seed dry weights were markedly higher than the 2 WAT treatment.
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Judul: Pertumbuhan dan Produksi Tanaman Jarak (Jatropha curcas L.) Pada Berbagai Taraf Dosis Pemupukan Nitrogen Dan Kalium
Abstrak: Penelitian ini dilakukan untuk mengetahui pengaruh pemupukan nitrogen dan kalium serta interaksinya terhadap pertumbuhan dan produksi tanaman jarak (Jatropha curcas L.). Penelitian dilaksanakan di Kebun Cikarawang, Darmaga, Bogor dari bulan Juli 2006 sampai bulan April 2007. Penelitian ini menggunakan rancangan faktorial dalam lingkungan Acak Kelompok (RAK). Perlakuan terdiri atas dua faktor yaitu pemupukan N dan pemupukan K. Tingkat pemupukan N terdiri dari 4 taraf yaitu 0 kg N/ha, 59.2 kg N/ha, 118.34 kg N/ha, 236.66 kg N/ha. Tingkat pemupukan K terdiri atas 3 taraf yaitu 0 kg K2O/ha, 100 kg K2O/ha, 200 kg K2O/ha. Setiap tanaman dipupuk P dengan dosis 200 kg P2O5/ha. Tiap perlakuan diulang tiga kali sehingga terdapat 36 satuan percobaan. Setiap satuan percobaan terdiri dari 4 tanaman. Tanaman yang digunakan telah berumur 20 minggu setelah tanam MST. Penelitian ini dilakukan pada lahan dengan ukuran petak berukuran 4 m x 8 m. Pemupukan dilakukan berdasarkan perlakuan yang diujicobakan, pupuk KCl diberikan sekaligus di bulan September, sedangkan pupuk Urea diberikan bertahap yaitu 2/3 dosis pada bulan September dan 1/3 dosis dua bulan kemudian. Kegiatan-kegiatan dalam pemeliharaan tanaman meliputi penyiangan dan pengendalian hama dan penyakit tanaman. Hasil penelitian menunjukkan bahwa perlakuan pupuk nitrogen meningkatkan semua parameter pertumbuhan vegetatif (tinggi tanaman, diameter batang, jumlah cabang, dan jumlah daun) dan produksi yang diamati hingga 56 minggu setelah tanam (MST). Perlakuan pupuk kalium meningkatkan semua parameter pertumbuhan vegetatif (tinggi, diameter, jumlah cabang dan jumlah daun) dan produksi hingga akhir pengamatan. Terdapat interaksi antara pemupukan nitrogen dan kalium pada parameter pertumbuhan tinggi tanaman, jumlah daun dan jumlah cabang. Dosis optimum N adalah 164.2 kg/ha dan K 100 kg/ha.
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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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