Judul: Determination of the Optimum Dose of P Fertilization on the  Cowpea (Vigna unguiculata L.)
Abstrak: Kacang tunggak merupakan tanaman Leguminoceae yang dapat dijadikan sebagai bahan pangan, pakan, dan bahan baku industri karena potensi hasil yang cukup tinggi. Varietas Albina IPB merupakan salah satu varietas dengan potensi hasil yang tinggi mencapai 3,88–4,69 ton ha-1 . Salah satu tindakan budidaya yang dapat diupayakan untuk mencapai potensi hasil salah satunya dengan pemupukan. Tujuan penelitian ini mempelajari pengaruh pupuk P dan memperoleh dosis pupuk P yang optimal untuk meningkatkan pertumbuhan dan produksi tanaman kacang tunggak. Penelitian ini dilaksanakan dari bulan Desember 2022 sampai Maret 2023 di Kebun Cikabayan Bawah. Pengamatan dilakukan di Laboratorium Pasca Panen dan Laboratorium Mikroteknik. Penelitian menggunakan Rancangan Kelompok Lengkap Teracak faktor tunggal yaitu lima taraf dosis pupuk P dan terdapat tiga ulangan. Hasil penelitian menunjukan pemberian pupuk dengan lima taraf perlakuan tidak menunjukan pengaruh yang nyata terhadap semua peubah pengamatan. Meskipun tidak berpengaruh nyata terdapat indikasi penurunan bobot kering daun tanaman terhadap penambahan dosis pupuk P. Hasil yang diperoleh tidak berpengaruh nyata tetapi terdapat indikasi peningkatan hasil pada bobot kering biji per tanaman, bobot bintil akar, indeks panen, bobot basah polong per ubinan, bobot kering polong per ubinan, dan bobot kering biji per ubinan. Meskipun demikian, belum diperoleh dosis optimum pemupukan P untuk meningkatkan pertumbuhan dan produksi tanaman kacang tunggak., Cowpea is a Leguminoceae plant that can be used as food, feed, and industrial raw materials due to its high yield potential. The Albina IPB variety is one of the varieties with high yield potential reaching 3,88–4,69 tons ha-1 . One of the cultivation actions that can be pursued to achieve potential result is fertilization. The purpose of this study was to study the effect of P fertilizer and to obtain the optimal dose of P fertilizer to increase the growth and production of cowpea plants. This research was conducted from December 2022 to March 2023 at the Lower Cikabayan Gardens. Observations were made at the Postharvest Labotary and the Microtechnic Laboratory. The study used a single factor randomized complete block design, namely five levels of P fertilizer doses, and there were three replications. The results showed that the application of fertilizer at five treatment levels did not show a significant effect on all observation variables. Although it did not have a significant effect, there were indications of a decrease in the dry weight of plant leaves with the addition of P fertilizer doses. The results obtained did not have a significant effect, but there were indications of an increase in yield on seed dry weight per plant, root nodule weight, harvest index, pod wet weight per tile, dry weight of pods per tile, and seed dry weight per tile. However, the optimum dose of P fertilization has not yeet been obtained to increase the growth and production of cowpea plants.
Keyword: Albina IPB, potensi hasil, pertumbuhan, produksi

Judul: Determination of Optimal Nitrogen Fertilizer for Increase Production of Cowpea (Vigna unguiculata L.)
Abstrak: Albina IPB merupakan salah satu varietas kacang tunggak yang memiliki banyak potensi, tetapi kurang dalam pemanfaatannya. Produksi kacang tunggak perlu lebih ditingkatkan, salah satu cara yang dapat dilakukan melalui perbaikan budidaya dalam hal pemupukan. Tujuan dari penelitian ini adalah mempelajari pengaruh dan menentukan dosis pupuk N yang optimal untuk pertumbuhan serta produksi kacang tunggak yang lebih tinggi. Kegiatan penelitian dilaksanakan mulai bulan November 2022 hingga Maret 2023 di Cikabayan Bawah. Pengamatan dilakukan di Laboratorium Pasca Panen dan Mikroteknik. Percobaan dilakukan dengan metode rancangan kelompok lengkap teracak sebanyak 3 kali ulangan. Penelitian terdiri dari faktor tunggal yaitu dosis pupuk N dengan lima taraf N yang diuji. Hasil penelitian menunjukkan bahwa pengaruh dari perlakuan dosis pupuk N tidak berbeda nyata antar taraf perlakuan. Meskipun tidak berbeda nyata, tetapi terdapat indikasi bahwa dengan adanya penambahan dosis pupuk N terdapat peningkatan hasil pada hampir seluruh peubah komponen hasil produksi., Albina IPB is a cowpea variety that has a lot of potential, but is lacking in utilization. Cowpea production needs to be further increased, one way that can be done is through improved cultivation in terms of fertilization. The purpose of this study was to study the effect and determine the optimal dose of N fertilizer for higher cowpea growth and production. Research activities were carried out from November 2022 to March 2023 in Cikabayan Bawah. Observations were made at the Postharvest and Microtechnic Laboratory. The experiment was carried out using a randomized complete block design with 3 replications. The study consisted of a single factor, namely the dose of N fertilizer with five levels of N being tested. The results showed that the effect of the N fertilizer dose treatment was not significantly different between treatment levels. Although not significantly different, there are indications that with the addition of N fertilizer doses there is an increase in yield in almost all of the production yield component variables.
Keyword: Albina IPB, Dosage of N Fertilizer, Fertilization, Recommendations, Yield Potential

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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