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: Effectiveness of Nutsedge (Cyperus rotundus L.) as Bioherbicide to Control Some Weed Species in Lowland Rice
Abstrak: Lahan tanaman padi di Indonesia yang luas masih belum bisa mencukupi kebutuhan pangan dalam negeri. Salah satu faktor penyebabnya adalah persaingan antara tanaman padi dan gulma. Inovasi yang dapat diterapkan dalam pengendalian gulma adalah aplikasi bioherbisida. Bioherbisida yang digunakan adalah bioherbisida dari senyawa alelopati yang dihasilkan tumbuhan. Senyawa alelopati dapat menekan bahkan mematikan tumbuhan lain di sekitarnya. Salah satu tumbuhan yang dapat dimanfaatkan untuk menjadi bahan baku bioherbisida adalah gulma teki (Cyperus rotundus L.). Penelitian ini bertujuan untuk mengetahui efektivitas bioherbisida berbahan baku teki pada lahan pertanaman padi sawah. Rancangan percobaan yang digunakan adalah rancangan kelompok lengkap teracak (RKLT) faktor tunggal dan tiga ulangan. Perlakuan terdiri dari kontrol (P0), pengendalian manual (P1), bioherbisida granul 22,5 kg tepung ha-1(P2), bioherbisida granul 45 kg tepung ha-1(P3), bioherbisida granul 67,5 kg tepung ha-1(P4), bioherbisida larutan 45 kg tepung ha-1(P5), herbisida pratumbuh Oksifluorfen 2 l ha-1(P6). Hasil percobaan menunjukan bahwa aplikasi bioherbisida teki formulasi granul dosis 67,5 kg ha-1dapat menekan pertumbuhan gulma Ludwigia octovalvis, Pistia stratiotes, dan Paspalum distichum dibandingkan dengan perlakuan tanpa penyiangan di lahan pertanaman padi. Aplikasi bioherbisida teki dapat meningkatkan hasil panen dan tidak menimbulkan fitotoksisitas terhadap tanamanpadi. Kata kunci : alelopati, bioherbisida, gulma, padi sawah, teki, Competition between weeds and rice is one of factors that decreasing rice productivity. An innovation that can be applied in weed control is the application of bioherbicides. The bioherbicide is usualy made of allelopathic compounds produced by plants. Allelopathic compounds can suppress some weeds. One of the plants that can be used as raw material for bioherbicides is nutsedge weed (Cyperus rotundus L.). The objective of the research was to determine the effectiveness of bioherbicide made from nutsedges (Cyperus rotundus L.) in rice fields. The experiment was designed as randomized complete block design with single factor and three replications. The treatments were without weeding (P0), manual weeding (P1), granule bioherbicide from nutsedge 22,5 kg ha-1(P2), 45 kg ha-1(P3), 67,5 kg ha-1(P4), solution bioherbicide 45 kg ha-1(P5), and Oxyfluorfen herbicide 2 l ha-1(P6). The results of the experiment showed that the application of bioherbicide with granule formulations at 67,5 kg ha-1could suppress the growth of Ludwigia octovalvis, Pistia stratiotes, and Paspalum distichum weeds compared to the without weeding treatment. The application of bioherbicide made from nutsedge could increase crop yields and did not cause fitotoxicity to rice plants. Keywords: allelopathy, bioherbicide, lowland rice, sedge, weed
Keyword: allelopathy, bioherbicide, lowland rice, sedge, weed

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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