Judul: Keefektifan Allelopati Teki ( Cyperus rotundus L.) Terhadap Penekanan Perkecambahan Biji Asystasia gangetica (L.) T. Nama NIM Enderson pada Berbagai Jenis Tanah
Abstrak: Some previous research indicated that allelophatic in nutsedge (Cyperus rotundus) has potential to be used as bioherbicide to suppress broadleaf weed seed germination. The aim of this research was to know the effect of various formulations nutsedge biomass in suppresing Asystasia gangetica germination, which is a serious problem in many plantation. Another purpose of this research was to know effect of different concentration of extract nutsedge to suppressing seed germination of A. gangetica on some types of soil. This research was conducted in Juni-October 2014 in Ecofisiology Plant Laboratory, Agronomy and Horticulture Department. The first experiment using a randomized complete design with 5 treatments formulation nutsedge biomass, these are fresh nutsedge, dried nutsedge, granule, powder and control. The second treatment using factorial randomized complete design with treatment of the extract concentration nutsedge 0 kg l-1, 1 kg l-1, 2 kg l-1, dan 3 kg l-1 and type soils treatment with different clay composition (kuarsa, regosol, andosol, latosol and podsolik). All treatment were conducted in 3 replicates. Result of this research show that all formulation of nutsedge effectively suppress A. gangetica seed germination compared with control. The type of soil gives significant effect on the suppresion of germination A. gangetica seed. In all types of soil application of nutsedge extract showed a tendency that higher concentration of nutsedge extract, higher pressing A. gangetica seed germination.
Keyword: Bogor Agricultural University (IPB), formulation, concentration, bioherbicide, allelophatic

Judul: Studi Potensi Alelopati Teki (Cyperus rotundus L.) sebagai Bioherbisida untuk Pengendalian Gulma Berdaun Lebar
Abstrak: This research was conducted at Seed and Technology Laboratory of IPB, Cikabayan Greenhouse, Darmaga, Bogor and Regional Health Laboratory, Jakarta from July 2011 until May 2012 to study the potency of allelochemical compounds from Cyperus rotundus L. as bioherbicide for broadleaf weed control (Asystasia gangetica, Borreria alata and Mimosa pigra). The research consisted of 3 experiments. The objective of the first experiment was to study breaking treatment of seed dormancy for Asystasia gangetica, Mimosa pigra and Borreria alata. The weed treatment were soaked in 50 0C warm water for 24 hours, soaked in 90 0C hot water and embedded in soil for 4 days and control. The result showed that burrying Borreria alata seed in the soil for 4 days, soaking Mimosa pigra seed in hot water could be used as dormancy breaking treatments. No dormancy breaking treatment needed for Asystasia gangetica. The second experiment was conducted to study the influence of C. rotundus extracts on pre-emergence of broadleaf weed. The treatments used 0.5, until 4.5 kg/L with interval 0.5 kg/L concentration of extract (C. rotundus biomass with aquadest). The third experiment was conducted to determine the effect of C. rotundus extracts, mixed with fresh and dried C. rotundus biomass with soil, mulched of fresh and dried C. rotundus biomass, compost and flour of C. rotundus to weed growth and developmentand soybean. The experiment was using completely randomized design in observation of germination and randomized block design in weed growth. The result showed that 1.0 kg/L concentration of C. rotundus extract caused lower weed seed germination but have no effect on soybean germination. Applications of C. rotundus biomass have no effect on the growth and development of weed and soybean. Application of C. rotundus extract 1.0 kg/L potentially can be used as pre-emergence bioherbicide.
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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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