Judul: Analisis Keragaman Pertumbuhan, Produktivitas dan Kandungan Nutrien Berbagai Varietas Brachiaria brizantha
Abstrak: Brachiaria brizantha memiliki beberapa varietas antara lain B. brizantha var. brauna, B. brizantha var. ecotype b4, B. brizantha var. ecotype eth. 13726, B. brizantha var. ecotype eth. 1377, B. brizantha var. ecotype eth. 13809, B. brizantha var. marandu, B. brizantha var. mg4, B. brizantha var. paiaguas, B. brizantha var. piata, B. brizantha var. toledo dan B. brizantha var. xaraes. Penelitian ini bertujuan untuk menganalisis keragaman produktivitas dan kandungan nutrisi berbagai varietas Brachiaria brizantha, sehingga diketahui varietas yang memiliki pertumbuhan, produksi dan kualitasnya. Pada 30 peneliti dari tahun 2010-2020, terdapat 7 parameter yang diamati dan dicatat di Microsoft Excel 2010. Parameter tersebut meliputi data pertumbuhan, produksi dan kualitas nutrien, yaitu produksi tanaman, bahan kering (BK), protein kasar (PK), total digestible nutrient (TDN), neutral detergent fiber (NDF) dan acid detergent fiber (ADF). Kemudian data dianalisis menggunakan software Rgui. Hasil penelitian menunjukkan bahwa varietas Brachiaria brizantha berpengaruh nyata terhadap tinggi tanaman pada musim hujan (P<0,05) dan musim kemarau (P<0,01), produksi pada musim kemarau (P<0,01), BK pada musim kemarau (P<0,01), PK pada musim kemarau (P<0,01), TDN pada musim hujan (P<0,01), NDF pada musim hujan (P<0,01) dan musim kemarau (P<0,05), serta ADF pada musim hujan (P<0,01) dan musim kemarau (P<0,01). Pertumbuhan, produksi dan kandungan nutrien terbaik pada B. brizantha var. xaraes., Brachiaria brizantha has several varieties, including B. brizantha var. brauna, B. brizantha var. ecotype b4, B. brizantha var. ecotype eth. 13726, B. brizantha var. ecotype eth. 1377, B. brizantha var. ecotype eth. 13809, B. brizantha var. marandu, B. brizantha var. mg4, B. brizantha var. paiaguas, B. brizantha var. piata, B. brizantha var. toledo dan B. brizantha var. xaraes. This study aims to analyze the productivity and nutrient content of various varieties of Brachiaria brizantha. Within 30 studies from 2010-2020, production and quality parameters were observed and recorded in Microsoft Excel 2010. These parameters include data on growth, production and nutrient quality, namely plant production, dry matter (BK), crude protein (PK), total digestible nutrients (TDN) and neutral detergent fiber (NDF). Then data was analyzed using Rgui software. The results showed that the Brachiaria brizantha varieties had a significant effect on plant height rainy seasons (P<0.05) and dry seasons (P<0.01), production dry seasons (P<0.01), BK dry seasons (P<0.01), PK dry seasons (P<0.01), TDN rainy seasons (P<0.01), NDF rainy seasons (P<0.01) and dry seasons (P<0.05), and ADF rainy seasons (P<0.01) and dry seasons (P<0.01). The best growth, production and nutrient content were obtained by Brachiaria brizantha var. xaraes.
Keyword: Brachiaria brizantha variety, growth, production, nutrient content

Judul: Optimization of Chicken Manure Fertilizer (Broiler) in  Supporting Productivity of Brachiaria humidicola in Jonggol Animal Science  Teaching and Research Unit (JASTRU)
Abstrak: Penelitian ini bertujuan untuk mengukur dosis pupuk kandang ayam yang memberikan hasil yang terbaik terhadap produktivitas rumput Brachiaria humidicola. Penelitian ini dilaksanakan di Unit Pendidikan dan Penelitian Peternakan Jonggol (UP3J). Penelitian dilakukan dengan menggunakan rancangan acak lengkap dengan pola petak terbagi (RAL split plot) dengan 5 perlakuan dan 4 ulangan, yaitu P1 = urea 150 kg ha-1, P2 = 5 ton ha-1 pupuk kandang ayam + urea 75 kg ha-1, P3 = 10 ton ha-1 pupuk kandang ayam + urea 75 kg ha-1, P4 = 15 ton ha-1 pupuk kandang ayam + urea 75 kg ha-1 dan P5 = 20 ton ha-1 pupuk kandang ayam + urea 75 kg ha-1. Hasil penelitian menunjukkan pupuk kandang ayam efektif meningkatkan jumlah tunas, jumlah stolon, panjang stolon, tinggi tanaman, produksi biomassa individu tanaman, warna tanah serta warna daun rumput Brachiaria humidicola. Dosis optimal dalam mendukung produktivitas rumput Brachiaria humidicola sebesar 20 ton ha-1 pupuk kandang ayam dan 75 kg ha-1 pupuk anorganik urea. Peningkatan dosis pupuk kandang ayam berkorelasi positif terhadap produksi biomassa rumput Brachiaria humidicola., The aim of this research were to measure the dose of chicken manure fertilizer that gives the best results on the productivity of Brachiaria humidicola. These experiment were conducted at Jonggol Animal Science Teaching and Research Unit (JASTRU). This research was designed by using split-plot design with 5 treatments and 4 replications, namely P1 = urea 150 kg ha-1, P2 = 5 tons ha-1 of chicken manure fertilizer + urea 75 kg ha-1, P3 = 10 tons ha-1 of chicken manure fertilizer + urea 75 kg ha-1, P4 = 15 tons ha-1 of chicken manure fertilizer + urea 75 kg ha-1 and P5 = 20 tons ha-1 of chicken manure fertilizer + urea 75 kg ha-1. The results showed that chicken manure fertilizer was effective in increasing the number of shoots, number of stolons, stolon length, plant height, individual plant biomass production, soil color and leaf color of Brachiaria humidicola. The optimal dose to support the productivity of Brachiaria humidicola is 20 tons ha-1 of chicken manure fertilizer and 75 kg ha-1 of urea. Increasing the dose of chicken manure fertilizer was positively correlated to the biomass production of Brachiaria humidicola.
Keyword: Brachiaria humidicola, chicken manure fertilizer, productivity, UP3J

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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