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: 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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