Judul: Growth and Production of Sorghum (Sorghum bicolor (L.) Moench) Varieties of Numbu at Various Doses and Placement of Fertilizers
Abstrak: Sorgum merupakan tanaman serealia dan berpotensi sebagai tanaman pangan alternatif, namun produktivitasnya masih rendah. Penelitian ini bertujuan untuk mengetahui dosis dan penempatan pupuk untuk meningkatkan pertumbuhan dan produksi tanaman sorgum. Penelitian ini dilaksanakan pada bulan Februari hingga Juli 2019 di Kebun Percobaan Cikabayan, Laboratorium Pengujian, dan Laboratorium Pasca Panen, Departemen Agronomi dan Hortikultura, Fakultas pertanian, IPB. Percobaan ini menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) faktorial. Faktor pertama adalah dosis pemupukan yang terdiri dari 25%, 50%, dan 100% dari dosis acuan yang digunakan (261 kg Urea, 100 kg SP-36, dan 150 kg KCl per hektar). Faktor kedua adalah penempatan pupuk yang terdiri dari (1) di sepanjang baris dalam di antara dua baris tanaman dan (2) di sepanjang baris di luar setiap baris tanaman. Pemberian dosis pupuk 25% dari dosis acuan meningkatkan pertumbuhan tinggi tanaman sorgum pada umur 8 dan 10 minggu setelah tanam dan menghasilkan hasil yang tidak nyata dibandingkan dosis lainnya. Penempatan pupuk tidak berpengaruh nyata terhadap pertumbuhan dan hasil sorgum., Sorghum is a cereal crop and has potential as an alternative food crop, but its productivity is still low. This research aimed to determine the dosage and placement of fertilizers to increase the growth and production of sorghum plants. This research was conducted from February to July 2019 at The Cikabayan Experimental Field Station, Testing Laboratory, and Post Harvest Laboratory, Departement of Agronomy and Horticulture, Faculty of Agriculture, IPB. The experiment used a factorial randomize complete block design (RCBD. The first factor was the fertilizer dose consisting of 25%, 50%, and 100% of the reference dose used (261 kg Urea, 100 kg SP-36, and 150 kg KCl per hectare). The second factor was the placement of fertilizers consisting of (1) along the row inside between two plant rows and (2) along the row outside each plant row. Giving a fertilizer dose of 25% of the reference dose increased the growth of sorghum plant height at 8 and 10 weeks after planting and resulted in a yield not significant to the others dose. The placement of fertilizer did not significantly affect the growth and result of the sorghum.
Keyword: dosage of fertilizers, growth, placement of fertilizer

Judul: Growth and Production of Sorghum Post Peanut Planting
Abstrak: Sorgum merupakan komoditas pangan bernilai ekonomi tinggi dan berpotensi dikembangkan di Indonesia. Produktivitas sorgum dapat ditingkatkan dengan menerapkan sistem budi daya yang baik, salah satunya rotasi tanaman dengan kacang-kacangan. Penelitian ini bertujuan menganalisis pertumbuhan dan produksi sorgum di lahan pasca penanaman kacang tanah serta menganalisis pengaruh pemupukan terhadap pertumbuhan dan produksi sorgum di lahan pasca penanaman kacang tanah. Penelitian menggunakan rancangan kelompok lengkap teracak (RKLT) pola tersarang (nested) dengan 2 faktor dan 4 ulangan. Faktor pertama yaitu jenis lahan (lahan non-pasca penanaman kacang tanah dan lahan pasca penanaman kacang tanah). Faktor kedua yaitu pemupukan (tanpa pupuk, pupuk anorganik, dan pupuk anorganik + pupuk kandang). Terdapat interaksi antara jenis lahan dan pemupukan terhadap diameter batang dan panjang malai. Penggunaan lahan pasca penanaman kacang tanah memberikan pertumbuhan dan komponen hasil sorgum yang lebih baik pada karakter jumlah daun, diameter batang, intensitas hijau daun, panjang daun, lebar daun, panjang malai, diameter malai, bobot basah malai, bobot basah brangkasan, dan bobot kering brangkasan. Pupuk anorganik maupun pupuk anorganik + pupuk kandang meningkatkan tinggi tanaman, jumlah daun, dan diameter batang. Pemupukan tidak meningkatkan komponen hasil sorgum., Sorghum is a food commodity that has high economic value and potential to be developed in Indonesia. Sorghum productivity can be increased by implementing a good cultivation system, such as crop rotation with legumes. The study aims to analyze the growth and production of sorghum on post peanut planting land and analyze the effect of fertilization on the growth and production of sorghum on post peanut planting land. The study used a nested randomized complete block design (RCBD) with 2 factors and 4 replications. The first factor was the type of land (not post peanut planting land and post peanut planting land). The second factor was fertilization (no fertilizer, inorganic fertilizer, and inorganic fertilizer + manure). There was an interaction between land type and fertilization on stem diameter and panicle length. The use of post peanut planting land provided better growth and yield of sorghum in terms of leaf number, stem diameter, leaf green intensity, leaf length, leaf width, panicle length, panicle diameter, panicle wet weight, stover wet weight, and stover dry weight. Inorganic fertilizer and inorganic fertilizer + manure increased plant height, leaf number, and stem diameter. Fertilization did not increase the yield of sorghum.
Keyword: nested, legume, crop rotation, Bioguma 1

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.
Keyword: