Judul: Pengaruh Perlakuan Invigorasi Pada Benih Yang Berbeda Tingkat Masak Terhadap Viabilitas Dan Vigor Benih, Pertumbuhan Tanaman, Dan Hasil Kacang Bogor (Vigna subterranea (L.) Verdcourt)
Abstrak: Bambara groundnut can be cultivated in marginal land, however, its productivity is low. In order to increase the productivity, high quality of seeds must be used. Two consecutive experiments were conducted in laboratory and field at Bogor Agricultural University from April to October 2010. Seeds of three maturity levels were harvested from farmer’s field in Sukabumi, April 2010. The seeds were dried down to 11.6% moisture content before being used. The objectives of the experiments were to evaluate effects of seed invigoration applied on bambara groundnut seeds of three maturity levels on seed vigor, plant growth, and yield. Laboratory experiment was arranged in a completely randomized design while field experiment was arranged in a completely randomized block design. In both experiments, two factors were applied, seed maturity and invigoration. There were three levels of seed maturity i.e. seeds harvested at 119, 122, and 125 days after planting (dap). Seed invigoration consisted of untreated, Rhizobium sp., matriconditioning, matriconditioning plus Rhizobium sp. Matriconditioning was conducted using ratio of seeds to carrier (burned rice hull) to water of 20:12:12 (g) for 3 days in air-conditioned room ca. 25 0C. Rhizobium sp. 0.3 g/100 g seeds was either applied on seeds just before planted or incorporated in matriconditioning. Results of the laboratory experiment showed that matriconditioning alone or matriconditioning plus Rhizobium sp. applied on seeds harvested at 122 daf or 125 dap improved seed vigor (speed of germination and index of vigor). However, there was no interaction occurred between the two factors in the field experiment. Seeds treated with matriconditioning plus Rhizobium sp. or harvested at 125 dap showed the best improvement in plant growth (plant height, number of leaves, number of branches) and yields (number and weight of pods).
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Judul: Hydration Dehydration Treatment Of Bambara Groundnuts (Vigna subterranea L. Verdc) Seed Vigor
Abstrak: Upaya yang dapat dilakukan untuk meningkatkan produktivitas kacang bambara antara lain adalah menjamin ketersediaan benih bermutu, namun terdapat kendala dalam penyediannya. Penelitian ini bertujuan mempelajari pengaruh hidrasi-dehidrasi sebagai perlakuan invigorasi terhadap viabilitas dan vigor benih kacang bambara (Vigna subterranea L. Verdc). Penelitian ini dilaksanakan pada bulan Juni hingga Agustus 2019 di Laboratorium Pengujian Benih, Departemen Agronomi dan Hortikultura, Institut Pertanian Bogor. Percobaan dirancang menggunakan rancangan acak lengkap (RAL) dengan dua faktor. Percoban dilakukan pada lanras Tasikmalaya. Faktor pertama adalah lot benih dipanen Maret 2019, lot benih dipanen Oktober 2017. Faktor kedua adalah perlakuan hidrasi-dehidrasi yang terdiri atas 5 taraf, yaitu kontrol, (perendaman dalam air selama 12 jam lalu dikeringkan 4 jam) pada suhu 28 o C-30 o C, suhu 38 o C-40 o C, suhu 28 o C-30 o C, suhu 38 o C-40 o C. Perlakuan hidrasi-dehidrasi mampu meningkatkan vigor benih kacang bambara dengan peningkatan nilai indeks vigor dari 15,9% menjadi 27% dan kecepatan tumbuh dari 9%etmal -1 menjadi 11%etmal -1., Effort that can be done to increase the productivity of bambara groundnuts include ensuring the availability of quality seeds, but there are obstacles in the process of providing the seeds. This research aims to study the effect of hydration- dehydration as an invigoration treatment on vigor and viability of two lots of bambara groundnut seeds (Vigna subterranea L. Verdc.). This research was conducted from June to August 2019 at Seed Testing and Storage Laboratory, Department of Agronomy and Horticulture, IPB University. The experiment was designed using a completely randomized design (CRD) with two factors. The experiment was conducted on the Tasikmalaya landraces. The first factor is the seed lot, harvested in March 2019, harvested in October 2017. The second factor is hydration-dehydration consisting of five levels, namely control, (soaking in water for 12 hours and then dried for 4 hours) at temperature 28 o C-30 o C, at temperature 38 o C-40 o C, at temperature 28 o C-30 o C, at temperature 38 o C-40 o C. Hydration-dehydration treatment was able to increase seed vigor of bambara groundnut seeds by increasing the vigor index value from 15.9 % to 27% and the speed of germination from 9%etmal -1 to 11%etmal -1 .
Keyword: Invigoration, Bogor Groundnuts, Seed deterioration, Viability

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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