Judul: Application of Granulated Coal Fly Ash and NPK Fertilization for Spinach (Ipomoea reptans)
Abstrak: Pembangunan jangka panjang di Indonesia diarahkan pada pembangunan ekonomi berbasis industri. Residu pembakaran batu bara berupa padatan salah satunya berupa abu terbang. Upaya untuk mengatasi masalah yang ada pada lahan bekas tambang di antaranya dengan pemanfaatan abu batu bara sebagai bahan tambahan untuk pupuk atau pembenah tanah. Penelitian ini bertujuan untuk mengetahui potensi perbaikan kelengkapan pupuk NPK melalui penambahan abu terbang pada berbagai komposisi dan dosis aplikasi terhadap pertumbuhan vegetatif dan produksi segar tanaman kangkung (Ipomoea reptans) pada media polibag. Penelitian dilakukan pada bulan Juli hingga September 2020 di Kebun Percobaan Leuwikopo Institut Pertanian Bogor. Penelitian ini menggunakan rancangan kelompok lengkap teracak (RKLT) dua faktor yaitu komposisi (100% abu terbang (K0), 100% NPK (K1), 90% NPK dan 10% abu terbang (K2), 80% NPK dan 20% abu terbang (K3), 67% NPK dan 33% abu terbang (K4), dan 50% NPK dan 50% abu terbang (K5)) dan dosis pemupukan (0 g polibag-1, 2,25 g polibag-1, 4,5 g polibag-1, 9 g polibag-1, dan 18 g polibag-1) yang terdiri atas 30 satuan percobaan yang diulang sebanyak 6 kali. Penambahan abu terbang memperbaiki kelengkapan kandungan mineral dalam pupuk NPK dengan memperbaiki pertumbuhan dan produksi kangkung segar. Penambahan abu terbang meningkatkan hara pada air perkolat., Indonesia's long-term development is directed at industrial-based economic development. The residue of burning coal in the form of solids, one of which is fly ash. Efforts to overcome the problems that exist in ex-mining land over the use of coal as additional material for planting media. This study aims to determine the potential for improvement of NPK fertilizer through the addition of abu terbang at various compositions and application doses on vegetative growth and production of spinach (Ipomoea reptans) on polybags media. The research was conducted from July to September 2020 at the Leuwikopo Experimental Garden, IPB University. This study used a two-factor Randomized Complete Block Design (RCBD), namely composition (100% fly ash (K0), 100% NPK (K1), 90% NPK and 10% fly ash (K2), 80% NPK and 20% fly ash (K3), 67% NPK and 33% fly ash (K4), and 50% NPK and 50% fly ash (K5)) and fertilization doses (0 g polybag-1, 2,25 g polybag-1, 4,5 g polybag-1, 9 g polybag-1, and 18 g polybag-1) consisting of 30 experimental units which were repeated 6 times. The addition of fly ash increases the water percolate nutrients.
Keyword: dosis, Ipomoea reptans, komposisi, pemupukan abu terbang, pencucian

Judul: Response of Three Varietas Water Spinach (Ipomea reptans  Poir) to Increased NPK Fertilization
Abstrak: Kangkung darat (Ipomea reptans Poir) merupakan komoditas hortikultura yang banyak dibudidayakan dan digemari karena waktu panennya yang cepat dan mudah dibudidayakan. Namun seiring berjalannya waktu produksi tanaman kangkung terus menurun setiap tahunnya. Penggunaan pupuk majemuk dan pemilihan varitas unggul merupakan salah satu solusi dan alternatif untuk meningkatkan produksi dan efisiensi budidaya. Penelitian ini bertujuan mendapatkan informasi interaksi dan respon tiga varietas kangkung terhadap pemberian dosis pupuk NPK yang berbeda pada pertumbuhan dan hasil. Penelitian ini dilakukan pada bulan April hingga Mei 2024 di Desa Cikura, Kabupaten Banjarnegara, Jawa Tengah. Penelitian ini menggunakan rancangan kelompok lengkap teracak dengan dua faktor dosis dan varietas yang terdiri atas tiga ulangan. Faktor pertama yaitu dosis pemupukan dengan 4 taraf dosis pemupukan yaitu 0 NPK, 0,5 g tan-1 NPK, 1 g tan-1 NPK, dan 1,5 g tan-1. Faktor kedua yaitu varietas menggunakan 3 varietas komersil yaitu Bangkok LP-1, Rajawali, dan Serimpi. Hasil penelitian menunjukkan bahwa dosis pupuk 1,5 g tan-1 mampu meningkatkan tinggi tanaman, jumlah daun dan berat segar tanaman. Varietas Bangkok LP-1 dapat meningkatkan pertumbuhan dan hasil tanaman kangkung. Hasil penelitian menunjukan tidak terdapat interaksi yang nyata antara dosis pupuk NPK dan tiga varietas kangkung terhadap pertumbuhan dan hasil tanaman kangkung, Water spinach (Ipomea reptans Poir) is a horticultural plant widely cultivated and favored due to its quick harvest time and ease of cultivation. Bu, as time goes by, water spinach production continues to decline every year. The use of compound fertilizers and the selection of superior varieties are among the solutions and alternatives to increase production and cultivation efficiency. This study aims to determine the effect of NPK fertilizer dosage on the growth and yield of three varieties of water spinach (Ipomea reptans Poir). The research was conducted from April to May in Cikura Village, Banjarnegara Regency, Central Java. This study used a randomized complete group design with two factors, dose and variety, consisting of three replications. The first factor is the fertilizer dose with 4 levels of fertilizer dose namely 0 NPK, 0.5 g tan-1 NPK, 1 g tan-1 NPK, dan 1.5 g tan-1. The second factor is the variety using 3 commercial varieties, namely Bangkok LP-1, Rajawali, and Serimpi. The research results showed that a fertilizer dose of 1.5 g tan-1 was able to increase plant height, number of leaves and fresh weight of plants. The Bangkok LP-1 variety can increase the growth and yield of kale plants. The results of the research showed that there was no real interaction between the dose of NPK fertilizer and the three varieties of kale on the growth and yield of kale plants.
Keyword: Bangkok LP-1, dosage, interaction

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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