Judul: Perkembangan hama dan penyakit tanaman padi (oryza sativa l.) Pada beberapa sistem budidaya
Abstrak: ABRIANI FENSIONITA. Perkembangan Hama dan Penyakit Tanaman Padi (Oryza sativa L) pada Beberapa Sistem Budidaya. Dibimbing oleh GEDE SUASTIKA, DADANG dan NINA MARYANA. Di Indonesia, budidaya padi saat ini masih sangat bergantung pada penggunaan pupuk anorganik dan pestisida sintetik. Penggunaan pestisida sintetik secara terus menerus dapat menimbulkan efek samping yang sangat merugikan seperti timbulnya hama baru, residu pada hasil pertanian dan pencemaran lingkungan. Dengan semakin meningkatnya kesadaran masyarakat terhadap kesehatan, maka pertanian organik mulai dipilih untuk menghasilkan bahan pangan aman (safe food) dan bersahabat bagi lingkungan (environmental friendly). Penelitian ditujukan untuk 1) membandingkan perkembangan hama dan penyakit tanaman padi pada sistem konvensional (urea 200 kg/ha, TSP 100 kg/ha, KCl 100 kg/ha dan aplikasi pestisida berkala), dengan sistem input rendah (bokashi 1 ton/ha, urea 100 kg/ha, TSP 50 kg/ha, KCl 50 kg/ha dan aplikasi pestisida tergantung serangan OPT), dan pertanian organik (bokashi 5 dan 10 ton/ha, tanpa aplikasi pestisida sintetik dan pupuk anorganik), 2) mengetahui keanekaragaman dan kelimpahan arthropoda dan 3) mengetahui keanekaragaman dan kelimpahan mikroorganisme pada sistem konvensional, input rendah dan pertanian organik. Berdasarkan pengamatan yang dilakukan selama dua musim tanam, tingkat serangan hama (penggerek batang) dan penyakit (tungro, kresek, bercak coklat dan hawar pelepah) pada ketiga sistem budidaya hampir sama. Keanekaragaman dan kelimpahan arthropoda dan mikroorganisme ditemukan lebih tinggi pada pertanian organik. Walaupun hasil panen gabah pada sistem konvensional lebih tinggi dari pada sistem lainnya, namun dari segi keamanan dan nilai jual beras, pertanian organik memberikan harga yang lebih tinggi dibandingkan dengan sistem pertanian konvensional maupun input rendah.
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Judul: Pest and Disease Incidences on Rice (Oryza sativa L.) Organic Farming System
Abstrak: Excessive utilization of both synthetic chemical fertilizers and pesticides in conventional farming system so far has created many problems such as environmental pollution, plant pest and disease resistance and resurgence, health problems, etc. These adverse effects promoted the conversion movement of farming system from conventional to organic. Modern organic farming system encourages farmers to use organic fertilizers, to control plant pests and diseases by using biological agents and cultivation management. The objectives of the research were (1) to analyze the incidence of pest and disease on the rice organic farming system, and (2) to know the effect of the organic farming system on diversity and abundance of arthropods and microorganism. The research was conducted in Situgede village, Bogor, West Java in two planting seasons that were rainy and dry seasons of 2007/2008. The treatments included five farming systems i.e. conventional (using urea 200 kglha, TSP 100 kg/ha, KCl 100 kglha and synthetic chemical pesticide); low-input (using bokashi 1 tonlha, urea too kglha, TSP 50 kg/ha, KCl 50 kg/ha and synthetic chemical pesticide); organic-5 (using bokashi 5 tonlha, without anorganic fertilizer and synthetic chemical pesticide); organik-lO (using bokashi 10 tonlha, without anorganic fertilizer and synthetic chemical pesticide); SRI (similar with organic-5, but different in irrigation and planting system). The result of the study showed that the incidences of pests and diseases in organic farming systems were almost the same as in those of conventional farming systems, either in rainy or dry season. Furthermore, diversity and abundance of arthropods and microorganism on organic farming system were higher than those of the conventional one. Ecosystem on organic farming system was likely more suitable for and therefore promoted the development of beneficial organisms. It was also found that organic farming systems were more profitable than the conventional ones.
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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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