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: 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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