Judul: Pengaruh Pemupukan Anorganik (N, P, K) dan Potensi Limbah Sereh Wangi sebagai Bahan Organik terhadap Pertumbuhan dan Produksi Jahe Gajah (Zingiber officinale Rosc.).
Abstrak: Exports of ginger from Indonesia in the last three years has declined because the quality of the ginger can not meet world market competitiveness. Suboptim cultivation techniques become a constraint in the development of the ginger plant coupled with the excessive use of synthetic chemical fertilizers that causes low soil capacity. The development of environmentally friendly technology to reduce the use of synthetic chemical fertilizers is expected to address the development problems of the ginger plant. Cultivation systems based on the utilization of in-situ organic materials such as waste of lemongrass (cymbopogon citratus) is widely available in the surrounding area of the ginger plant need attention so that the empowerment of local input and medicinal needs can be realize. The research aims to determine the effect of some several of organic materials and inorganic fertilizers (N, P, K) on the growth and production of young ginger, and weed growth. The research conducted at Bogor Agricultural University, Experimental Station, Cikabayan, Darmaga, Bogor, started September 2011 to April 2012 and used a split-plot design. The main plot consisted of organic materials consisting of granules (20 ton / ha), Cymbopogon citratus compost buried in soil (20 t / ha), Cymbopogon citratus compost mulch (20 t / ha) and without organic fertilizer as controls. Sub plot are inorganic fertilizer consisted of ½ doses (N, P, K), 1 doses (N, P, K), 2 doses (N, P, K) and without inorganic fertilizer. Organic materials and inorganic fertilizer did not significantly affect the growth component of ginger. Plants treated with ½ doses of inorganic fertilizer showed the highest dry weight of rhizomes and significantly different with 2 doses and plant resistance to disease is 54,98%. Combined treatment of lemongrass compost buried in soil and inorganic fertilizer showed the higest dry weight of total weeds, but combined treatment of lemongrass compost mulch and inorganic fertilizer showed the lowest dry weight of total weeds. Lemongrass can be used as the source of organic fertilizer and herbicid, depending on the method used and treatment.
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Judul: Respon Pertumbuhan Jahe Putih Kecil (Zingiber officinale var. Amarum) terhadap Pemupukan pada Media Tanpa Tanah.
Abstrak: Small ginger cultivation still have an issue, it is Ralstonia solanacearum bacteria that causes quite large yield loss. The character of Ralstonia solanacearum is soil borne and can survive a long time in the soil, so that the study was conducted using media without soil which is a mixture of coconut coir dust (cocopeat) and rice husk. The research aims to determine the growth response of small white ginger in a mixture of coconut coir media (cocopeat) and rice husk media, with the intake of certain fertilizers. The experiment was conducted in Greenhouse of Balai Penelitian Tanaman Rempah dan Obat (Balittro), Bogor, West Java Cimanggu from September 2014 to February 2015. The study using a randomized Complete Block Design Group (RKLT) one factor with six treatments and four repetition. Treatment in the form of a complete fertilizer dose applications, among others; P0 (0 g / l) as a control, P1 (1 g / l), P2 (2 g / l), P3 (3 g / l), P4 (4 g / l), and P5 (5 g / l) , The results showed that the dosage of fertilizers affect plant height, number of leaves, leaf length, height and number of tillers but had no effect on stem diameter, whereas for production factor variable dosage of fertilizer affect root length, number of roots, rhizome weight, fresh weight biomass and the dry weight of biomass but did not affect the fresh weight and dry weight of root. Small white ginger can grow well in the mixture rice husk and coconut coir dust (cocopeat) media, a dose that produces the best rhizome weight is 3 g/l (P3).
Keyword: white small ginger, rice husk, cocopeat

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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