Judul: Identification of Phenolic Compound from Different Accessions of Cyperus rotundus L. and the Effect on Germination of Borreria alata (Aubl.) DC
Abstrak: Teki (Cyperus rotundus L.) adalah salah satu gulma yang sangat penting di dunia karena kemampuannya dalam menekan produktivitas tanaman dan sulit untuk dikendalikan. Selain menghambat pertumbuhan tanaman, teki juga dapat menghambat pertumbuhan gulma lain sehingga dapat digunakan sebagai alat manajemen gulma. Teki mengandung senyawa alelokimia, salah satu senyawa yang banyak ditemukan berasal dari golongan fenol. Kelimpahan senyawa fenol diduga dipengaruhi oleh faktor lingkungan antara lain perbedaan tempat tumbuh. Karena kemampuan adaptasi teki yang tinggi, diduga kandungan senyawa fenol teki dari aksesi yang berbeda serta kemampuannya dalam menekan pertumbuhan gulma lain juga berbeda-beda., Purple nutsedge (Cyperus rotundus L.) is one of the important weeds in the world because of its ability to suppress the production of crops and difficult to control. C. rotundus residues can suppress the growth of others weeds. C. rotundus contains allelochemical compound such as phenolic compounds. The abundance of phenolic compounds were affected by environmental factor such as different growth location. Because of the adaptation ability of C. rotundus, there are assumption that the content of phenolic compound of C. rotundus from different accessions and the ability to suppress the growth of other weeds also have the different.
Keyword: Allelopathy, bioherbicide, organic farming, purple nutsedge, weed management

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: 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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