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: Application of K Fertilizer for Increased Yield of Cowpea Plants (Vigna unguiculata L.)
Abstrak: Kacang tunggak (Vigna unguiculata L.) merupakan tanaman Leguminoceae yang berpotensi menjadi alternatif substitusi kedelai karena mengandung gizi yang tinggi. Produksi kacang tunggak masih rendah sehingga diperlukan upaya perbaikan budidaya untuk meningkatkan hasil panen melalui pemupukan. Varietas Albina IPB merupakan salah satu varietas yang prospektif dengan potensi hasil mencapai 3,88-4,69 ton ha-1. Penelitian ini bertujuan mempelajari pengaruh pupuk K dan menentukan dosis optimum pupuk K untuk meningkatkan pertumbuhan dan produksi kacang tunggak. Penelitian dilaksanakan di Kebun Cikabayan Bawah dari bulan Desember 2022 sampai Maret 2023. Pengamatan dilakukan di Laboratorium Pasca Panen dan Mikroteknik. Rancangan Percobaan yang digunakan adalah Rancangan Kelompok Lengkap Teracak (RKLT) sebanyak tiga ulangan dengan faktor tunggal yaitu lima taraf dosis pupuk K. Hasil penelitian menunjukkan bahwa pengaruh dari perlakuan dosis pupuk K tidak berpengaruh nyata terhadap semua peubah yang diamati. Meskipun tidak berpengaruh nyata, terdapat indikasi penurunan bobot kering akar tanaman terhadap penambahan dosis pupuk K. Peubah komponen hasil yang menunjukkan indikasi peningkatan hasil pada setiap penambahan pupuk K yaitu bobot basah polong per tanaman, bobot kering polong per tanaman, jumlah polong per tanaman, bobot 100 biji per tanaman, indeks panen, bobot basah polong ubinan, bobot kering biji ubinan, dan produktivitas. Meskipun begitu, belum dapat ditentukan dosis optimum dari lima taraf dosis pupuk K yang diujikan., Cowpea (Vigna unguiculata L.) is a Leguminoceae plant that has the potential to be an alternative substitute for soybeans because it contains high nutrition. Cowpea production is still low, so efforts to improve cultivation are needed to increase yields by improving cultivation technique, including optimization of fertilizer application. The Albina IPB variety is one of the prospective varieties with a potential yield of 3,88-4,69 tons ha-1. This study aims to study the effect of K fertilizer and determine the optimum dose of K fertilizer to increase the growth and production of cowpea. The research was carried out at the Lower Cikabayan Gardens from December 2022 to March 2023. Observations were made at the Post-Harvest and Microtechnic Laboratory. The experimental design used was a Completely Randomized Group Design (RKLT) with three replications with a single factor, namely five levels of K fertilizer doses. The results showed that the effect of the K fertilizer dose treatment had no significant effect on all observed variables. Although it had no significant effect, there were indications of a decrease in the dry weight of plant roots with the addition of K fertilizer doses. The yield component variables that indicated an increase in yield with each addition of K fertilizer were the wet weight of pods per plant, the dry weight of pods per plant, the number of pods per plant, the weight 100 seeds per plant, harvest index, fresh weight of tiled pods, dry weight of tiled seeds, and productivity. Even so, it has not been possible to determine the optimum dose of the five K fertilizer dose levels tested.
Keyword: Albina IPB, pemupukan, pupuk kalium, dosis optimum, dosis pupuk, Albina IPB, fertilization, potassium fertilizer, optimum dose dose level

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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