Judul: Efektivitas Fungi Mikoriza Arbuskula dalam Mempengaruhi Produktivitas Rumput Gajah (Pennisetum purpureum Schum.) Berdasarkan Periode Pemanenan Berbeda
Abstrak: Salah satu jenis hijauan makanan ternak (HMT) yang produktif, kandungan gizinya baik, dan telah banyak dikembangkan di petenakan rakyat yakni Pennisetum purpureum Schum. atau yang lebih dikenal di Indonesia dengan rumput gajah. Permupukan yang dilakukan untuk meningkatkan produksi hijauan sering kali tidak sebanding dengan tingkat produksi dan tingkat pencemaran pupuk yang dihasilkan. Penggunaan fungi mikoriza arbuskula (FMA) diharapkan dapat menjadi teknologi alternatif ramah lingkungan dan efisiensi biaya pupuk bagi peternak dalam meningkatkan produksi HMT. Penelitian ini bertujuan untuk mengetahui tingkat produksi rumput gajah yang di inokulasi mikoriza berdasarkan periode panen berbeda dan mengetahui produktivitas rumput gajah dengan pengurangan pupuk dan penambahan FMA. Penelitian ini menggunakan Rancangan Acak Lengkap Pola Faktorial dengan 2 perlakuan dan 3 ulangan. Perlakuan pertama adalah pupuk: Po (kontrol), P₁ (100% dosts pupuk), dan P2 (50% pupuk dosis dan diinokulasi FMA). Faktor kedua adalah harpanen H30 (hari panen ke 30), H50 (hari panen ke 50), dan H60 (hari panen ke 60). Vaßabel yang diukur adalah pertambahan tinggi tanaman setiap minggu yang diukur setelah periode panen pertama, produksi berat kering pada periode panen pertama, produksi berat kering pada periode panen kedua, dan persentase infeksi FMA. Perlakuan P2H60 dengan inokulasi 10 gram FMA dan dosis pupuk 50% (SP36 75 kg/ha, KCl 75 kg/ha, pupuk kandang 2 ton/ha, dan urea 100kg/ha) pada hari pemotongan ke 60 rumput gajah memperoleh produksi terbaik, baik pada periode pertama maupun kedua dan lebih efektif dan efisien dalam penggunaan pupuk…
Keyword: Arbuscular  Mychorrizal Fungi (AMF), Pennisetum purpureum Schum., Elephant grass, Productivity

Judul: Efektivitas Fungi Mikoriza Arbuskula (FMA) dalam Memperbaiki Produktivitas Rumput Gajah (Pennisetum purpureum Schum.) Berdasarkan Periode Pemanenan
Abstrak: The use of arbuscular mycorrhizal fungi (AMF) was expected to be an alternative environmentally friendly technology and efficiency of fertilizer to increase the productivity of forage. This study was aimed to determine the level of production of elephant grass (Pennisetum purpureum Schum.) inoculated by AMF and fertilizer dose reduction based on different harvesting period. This research used Completely Randomized Factorial Design with 2 treatments and 3 replications. The first treatment was fertilizer: P0 (control), P1 (100% fertilizer dose), and P2 (50% fertilizer dose and inoculated by AMF). The second factor was the interval of harvest H30 (30th day of harvest), H50 (50th day of harvest, and H60 (60th day of harvest). Variables measured were plant height increment of each week, the production of dry weight on the first harvesting period, the production of dry weight on second harvesting period, and percent of infection AMF. It can be concluded that the P2H60 treatment with 10 grams of AMF inoculation and fertilizer dose 50% (SP36 75 kg/ha, KCl 75 kg/ha, manure 2 ton/ha, and urea 100 kg/ha) on 60th day of harvest elephant grass get the best production, either the first and second periods and more effective and efficient use of fertilizer.
Keyword: 

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: