Judul: Pengaruh Pupuk Magnesium (Mg) Terhadap Produksi dan Serapan Hara N, P, K, Ca, Mg Tanaman Kacang Hijau di Latosol Darmaga
Abstrak: Magnesium nutrient is a part of chlorophyl substance. The deficiency of Mg in the plant will decrease. The objective of this research was to determine the effect of Magnesium Fertilizer (MgO) on production and uptake of Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca) and Magnesium (Mg) of mung bean plant in Latosol Darmaga. The research design used Randomized Complete Block Design, with consist of 8 treatments were control, NPK Std, NPK Std + Kieserit, NPK Std + MgO 1, NPK Std + MgO 2, NPK Std + MgO 3, NPK Std + MgO 4, NPK Std + MgO 5 with each treatments had 3 replications. The research result showed that the addition treatment of MgO generally increased the plant height and mung bean production (total beans weight /pot and beans weight of 50 grains), especially to the treatment of NPK Std+MgO 3. Analysis of plant and soil showed that the MgO fertilizer tend to reduce content and uptake of Mg in plant leaves, but tend to increase the content and uptake of K and Ca in leaves while treatment of MgO fertilizer significantly increased exchangeable Mg (exch Mg) of soil and whereas exchangeable Ca was not different.
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Judul: Pengaruh pemberian pupuk magnesium(Mg) terhadap kadar klorofil total daun, dan serapan hara Mg tanaman kacang tanah(Arachis hypogaea L.) pada podsolik Jasinga dan Latosol Darmaga
Abstrak: Magnesium (Mg) merupakan salah satu hara makro esensial dan merupakan satu-satunya unsur logam yang menyusun molekul klorofil. Dalam hal ini Mg berperan sebagai aktivator spesifik dari beberapa enzim. Kekurangan hara Mg akan menghambat proses pembentukan klorofil yang secara tidak langsung akan mempengaruhi proses fotosintesis. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian pupuk Mg terhadap kadar klorofil-total daun dan serapan hara Mg tanaman kacang tanah yang ditanam pada Podsolik Jasinga dan Latosol Darmaga. Penelitian dilaksanakan selama 4 bulan, dimulai dari bulan November 2004 sampai Februari 2005. Percobaan ini menggunakan Rancangan Acak Lengkap Faktorial yang terdiri atas dua faktor. Faktor pertama adalah "jenis tanah", yang meliputi Podsolik Jasinga dan Latosol Darmaga, dan faktor kedua yaitu "dosis pupuk Mg", yang terdiri dari 4 taraf perlakuan (0 ppm Mg [M0], 50 ppm Mg [M1], 125 ppm Mg [M2], dan 250 ppm Mg [M3]. Tiap perlakuan diulang sebanyak 3 kali, sehingga terdapat 24 satuan percobaan (2 jenis tanah x 4 taraf Pupuk Mg x 3 ulangan). Setiap satuan percobaan ditanami lima benih tanaman kacang tanah, dan setelah tanaman berumur 1 minggu disisakan satu tanaman yang paling baik pada tiap pot. Analisis statistik yang digunakan dalam penelitian ini adalah sidik ragam dan uji Duncan. Hasil penelitian ini menunjukkan bahwa pemberian pupuk Mg tidak berpengaruh nyata terhadap kadar klorofil-total daun tanaman kacang tanah, namun ada kecenderungan peningkatan kadar klorofil-total daun dengan meningkatnya taraf pupuk Mg, sedangkan jenis tanah berpengaruh nyata terhadap kadar klorofil-total daun tanaman kacang tanah. Kadar klorofil-total daun tanaman yang ditanam pada Latosol Darmaga lebih tinggi daripada di Podsolik Jasinga. Pemberian pupuk Mg dan jenis tanah berpengaruh nyata terhadap serapan hara Mg bagian atas tanaman kacang tanah. Peningkatan taraf pupuk Mg cenderung meningkatkan serapan hara Mg bagian atas tanaman kacang tanah. Serapan hara Mg bagian atas tanaman pada Latosol Darmaga lebih tinggi daripada di Podsolik Jasinga.
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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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