Judul: Respon Pemupukan dan Varietas terhadap Produksi Kacang  Tunggak (Vigna unguiculata subsp unguiculata (L.) Walp)
Abstrak: Kebutuhan konsumsi kedelai dalam negeri yang lebih tinggi dibandingkan dengan produksinya menjadikan Indonesia cenderung mengimpor kedelai sebanyak 2,67 juta ton kedelai (BPS 2019). Dalam rangka meminimalisir ketergantungan impor ini diperlukan substitusi kacang-kacangan lokal. Salah satunya ialah kacang tunggak yang toleran terhadap lahan masam dengan potensi hasil biji 1000–1200 kg ha-1. Untuk mencapai potensi produksinya perlu didapatkan teknik produksi yang terbaik untuk varietas unggul ini. Penelitian bertujuan mendapatkan dosis pupuk NPK terbaik pada pertumbuhan dan produksi 2 varietas kacang tunggak. Penelitian dilakukan di KP Cikarawang Bogor pada bulan Februari–Mei 2021. Penelitian menggunakan rancangan kelompok lengkap teracak (RKLT) dengan varietas dan pemupukan NPK sebagai perlakuan dan terdapat tiga ulangan. Hasil analisis sidik ragam menunjukan bahwa penelitian ini belum mendapatkan dosis terbaik pemupukan NPK pada varietas kacang tunggak Albina dan Uno. Namun demikian ada kecenderungan pemupukan NPK berpengaruh nyata meningkatkan produktivitas dan bobot biji ubinan kacang tunggak pada 8 MST pada taraf 5%. Terdapat keragaman nyata antar varietas pada parameter bobot daun kering pada 6 MST, jumlah polong, bobot polong basah per tanaman, bobot polong kering per tanaman, bobot polong ubinan, bobot biji ubinan dan produktivitas pada umur tanaman 8 MST. Keragaman nyata antar varietas juga terdapat pada panjang polong, jumlah polong, bobot polong basah per tanaman, bobot polong kering per tanaman, bobot polong ubinan, bobot biji kering dan produktivitas pada umur tanaman 9 MST., The need of domestic soybean consumption which is higher than its production makes Indonesia import 2,67 million tons of soybeans (BPS 2019). In order to minimize this dependence on imports, it is necessary to substitute local beans. One of them is cowpea which is tolerant to acid soil with a potential seed yield of 1000 – 1200 kg ha-1. To achieve its production potential, it is necessary to obtain the best production techniques for this superior variety. The aim of the study was to obtain the best dose of NPK fertilize on the growth and production on 2 variety of cowpea. The study was conducted at Cikarawang Experimental Field IPB in February-May 2021. The study used a completely randomized group design (RKLT) with three replications. The results of analysis of variance showed that this research has not yet obtained the best dose of NPK fertilization on Uno and Albina varieties. However, there are indications that NPK fertilization significantly increases the productivity and weight of cowpea tile seeds at the age of 8 WAP. There are significant variations between varieties on dry leaf weight at the age of 6 WAP, number of pods, wet pod weight per plant, dry pod weight per plant, tile pod weight, seed weight of tiles and productivity at 8 WAP. There also significant of variances between varieties on parameter pod length, pod number, wet pod weight per plant, dry pod weight per plant, tile pod weight, dry seed weight and productivity at 9 WAP.
Keyword: Cowpea variety Albina and Uno, Fertilization, Variety

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: 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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