Judul: Impact of N, P, K Fertilization and Pruning to Increase Cowpea (Vigna unguiculata L.) Seed Production and Quality
Abstrak: Penelitian bertujuan mengidentifikasi untuk memperoleh pengaruh pemupukan N, P, K dan pemangkasan terhadap peningkatan produksi dan mutu benih kacang tunggak (Vigna unguiculata L.). Penelitian menggunakan rancangan perlakuan Split Plot dalam Rancangan Kelompok Lengkap Teracak (RKLT), masing-masing dengan tiga ulangan. Petak utama adalah pemangkasan yang terdiri dari tanpa pangkas (P0) dan pangkas (P1), sedangkan anak petak adalah tiga dosis pupuk N, P, K yang terdiri dari D1 (Urea 100 kg ha-1, SP-36 200 kg ha-1, KCl 150 kg ha-1), D2 (Urea 100 kg ha-1, SP-36 250 kg ha-1, KCl 175 kg ha-1), dan D3 (Urea 100 kg ha-1, SP-36 275 kg ha-1, KCl 200 kg ha-1). Pemupukan N, P, K dan pemangkasan tidak berpengaruh terhadap karakter vegetatif yaitu daya tumbuh, jumlah cabang, dan tinggi tanaman, serta komponen produksi seperti produksi petak-1, jumlah polong tanaman-1, bobot benih tanaman-1, jumlah benih polong-1, bobot polong tanaman-1, dan bobot 1000 butir benih, namun berpengaruh nyata terhadap interaksi bobot 1000 butir benih. Kedua perlakuan juga berpengaruh nyata pada komponen mutu benih seperti daya berkecambah, indeks vigor, dan Berat Kering Kecambah Normal (BKKN), tetapinamun tidak berpengaruh nyata terhadappada kecepatan tumbuh dan potensi tumbuh maksimum. Secara umum, perlakuan tersebut dapat diterapkan untuk meningkatkan mutu benih dalam produksi benih kacang tunggak., This study investigated the effect of N, P, K fertilization and pruning treatment to increase cowpea yield and seed quality. The experiment was arranged in a split-plot with a randomized complete block design, with three replications. The main plot was pruning treatment, i.e. pruning and control, while the subplot was three fertilizer doses of N, P, K i.e. 100 kg ha-1 Urea – 200 kg ha-1 SP-36 – 150 kg ha-1 KCl (D1), 100 kg ha-1 Urea – 250 kg ha-1 SP-36 – 175 kg ha-1 KCl (D2), and 100 kg ha-1 Urea – 275 kg ha-1 SP-36 – 200 kg ha-1 KCl (D3). N, P, K fertilization and pruning treatment didn’t affect to vegetative characters such as seed germinated in the field, branches number, and plant height. Both treatments also didn’t affect yield components such as yields plot-1, pods number plant-1, seeds weight plant-1, seeds number pod-1, pods weight plant-1, and 1000 seeds weight, but significantly affected interaction of the 1000 seeds weight. A significant effect of both treatments was observed on seed quality such as seed germination, vigor index, and normal seedling’s dry weight, however, didn’t affect other character such as germination speed and maximum growth potential. Generally, the treatments could be applied to increase the seed quality in cowpea seed production.
Keyword: cowpea, fertilizer dose, seed viability, pruning, cultivation technique

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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