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: 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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