Judul: Pengaruh Jenis Pupuk dan Dekomposer terhadap Pertumbuhan dan Produksi Padi Organik
Abstrak: Field experiment was carried out in Cikarawang, Dramaga, Bogor from November 2011 to March 2012. The objective of the research was to study the effect of fertilizer types and decomposer on growth and yield of organic rice. The experiment used factorial-randomized complete block design with fertilizer combinations (15 ton chicken manure ha-1 and 5 ton Tithonia diversifolia ha-1, 10 ton chicken manure ha-1 and 5 ton Tithonia diversifolia ha-1, and 10 ton chicken manure ha-1 and 5 ton rice straw ha-1) as the first factor and decomposer application (using decomposer and without decomposer) as the second factor. Organic fertilizer types significantly affected root wet weight, nutrient content of P and K in leaves. Rice productivities were not significantly different with fertilizer combinations 15 ton chicken manure ha-1 and 5 ton Tithonia diversifolia ha-1, 10 ton chicken manure ha-1 and 5 ton Tithonia diversifolia ha-1, and 10 ton chicken manure ha-1 and 5 ton rice straw ha-1, they were 2.28, 2.22, and 2.16 ton dry seed ha-1, respectively. Decomposer application significantly affected the number of tillers at 8 week after planting, leaf color at 5 weeks after planting, nutrient content of P in leaves and panicle length. Rice yield with decomposer application and without decomposer were 2.25 and 2.19 ton ha-1, respectively, and they were not different.
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Judul: Pengaruh jenis pupuk dan dekomposer terhadap pertumbuhan dan produksi padi organik
Abstrak: Percobaan ini dilaksanakan pada bulan November 2011 sampai dengan Maret 2012 di Kebun Percobaan IPB, Cikarawang, Bogor. Rancangan yang digunakan adalah Rancangan Kelompok Lengkap Teracak Faktorial, dua faktor dan empat ulangan. Faktor pertama, terdiri atas tiga macam kombinasi pupuk organik, yaitu 15 ton pupuk kandang ayam dengan 5 ton Tithonia diversifolia per hektar, 10 ton pupuk kandang ayam dengan 5 ton Tithonia diversifolia per hektar dan 10 ton pupuk kandang ayam dengan 5 ton jerami per hektar. Faktor ke-2, terdiri atas dua jenis perlakuan yaitu dengan aplikasi dekomposer dan tanpa aplikasi dekomposer. Selain itu juga dilakukan penanaman 3 petak sebagai pembanding dengan perlakuan A (10 ton jerami, 5 ton pupuk kandang ayam dengan 0.4 ton pupuk kandang ayam per hektar yang dicairkan), B (10 ton jerami, 5 ton pupuk kandang ayam per hektar dengan aplikasi dekomposer), dan C (10 ton Jerami dan 5 ton pupuk kandang ayam per hektar). Data diolah menggunakan uji F dan apabila menunjukkan nyata dilanjutkan dengan uji DMRT (Duncan Multiple Range Test) pada taraf kesalahan 5%. Khusus untuk melihat perbandingan antara 6-kombinasi perlakuan dengan 3 pembanding, dilakukan uji t-student.
Keyword: Chicken manure, Decomposer, Organic rice, Rice straw, Tithonia diversifolia

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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