Judul: Ecological Observation of Kebar Papua Natural Grassland and Productivity Test of Banondit (Biophytum petersianum Klotzsch) with Nitrogen Fertilizer and Defoliation Intervals
Abstrak: The objectives of the study were to observe the ecological aspect of Kebar natural grassland in terms of botanical composition, carrying capacity, association index, species composition, species dominance and banondit productivity due to the effect of nitrogen fertilizer and the different of defoliation interval. The experiment was conducted by using a Factorial Completely Randomize Design with nitrogen fertilizer as the first factor (0, 50, 100, 150 kg N/ha) and the second was defoliation intervals (40, 60, 180 days) with 5 replications. The result of ecological aspect showed that the botanical composition was consisted of Imperata cylindrica (59%), weed (24%), banondit (9%) and legume (8%). Imperata cylindrica was a dominant species in Kebar Natural pasture with high value of important index (INP) (31.05), species diversity was less than one and they have high related association (0.67-0.70) beside banondit and the other species. Prediction of carrying capacity for the area of 622.2 ha was 777.75 AU/ha/year. Increasing nitrogen fertilizer up to 150 kg/ha and interval of defoliation 180 days resulted better performance than the other treatment combination. This treatment showed an increased in plant high, number of ligule leaves, fresh and dry weight of crown, dry matter production and organic matter constituent. Thus, banondit was found as a potential source for feed.
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Judul: Effect of Lime and Cow Dung on Soil Chemical Properties for Growth and Production of Napier Grass (Pennisetum purpureum)
Abstrak: Upaya meningkatkan produksi sapi potong adalah dengan cara memperbaiki pakan ternak. Kondisi lahan yang kurang subur menjadi pembatas untuk mendapatkan sumber pakan hijauan. Maka, diperlukan hijauan yang memiliki produktivitas tinggi dan mampu tumbuh pada berbagai jenis lahan seperti rumput gajah. Lahan di Bangka Belitung umumnya terdiri atas lahan kering yang mempunyai tingkat kesuburan tanah yang rendah. Usaha meningkatkan kesuburan tanah dapat dilakukan melalui pengapuran dan pemupukan. Penelitian ini bertujuan untuk mengetahui pengaruh kapur dan pupuk kandang sapi (pukan) terhadap sifat kimia tanah serta pertumbuhan dan produksi rumput gajah. Percobaan ini merupakan percobaan faktorial dua faktor yang ditempatkan dalam rancangan acak kelompok (RAK). Faktor pertama adalah kapur dengan dua taraf, yaitu tanpa kapur (K0) dan kapur 3 ton/ha (K1). Faktor kedua adalah pukan dengan empat taraf, yaitu: tanpa pukan (P0), pukan 10 ton/ha (P1), pukan 20 ton/ha (P2), dan pukan 30 ton/ha (P3). Sifat kimia tanah yang diamati yaitu pH, C-organik, N-total, KTK, Ca dd, Mg dd, K dd, P tersedia, dan hara mikro (Fe, Mn, Cu, dan Zn) tersedia. Parameter pertumbuhan dan produksi yang diamati adalah tinggi tanaman, jumlah anakan, bobot basah, dan bobot kering. Hasil penelitian menunjukkan bahwa kapur 3 ton/ha (K1) mampu meningkatkan nilai pH, KTK, Ca dd, Mg dd, dan P tersedia. Pukan dapat meningkatkan C-organik, KTK, Ca dd, Mg dd, P tersedia, Fe dan Zn tersedia. Pukan, kapur, dan interaksinya berpengaruh nyata terhadap tinggi tanaman dan jumlah anakan, namun terhadap bobot basah dan bobot kering hanya pukan dan kapur yang berpengaruh nyata, sedangkan pengaruh interaksinya tidak nyata. Semakin banyak pukan yang diberikan, semakin baik pertumbuhan dan produksi rumput gajah., Improving animal feed is increased the production of beef cattle. The condition of the soil that was less infertile, as a barrier to getting forage sources of feed. So, we need forages that have high productivity and can grow on various types of land, such as napier grass. Bangka Belitung’s land consisted of dry land that has a low level of soil fertility. It can be increased by liming and fertilizing. This study aimed to determine the effect of lime and cow dung on the chemical properties for soil, growth and production of napier grass. This experiment was two-factor factorial experiment that consisted of two level of lime: without lime (K0) and lime 3 ton/ha (K1); and 4 levels of cow dung: 0 ton/ha(P0); 10 ton/ha (P1); 20 ton/ha (P2); and 30 ton/ha (P3). These treatment were replicate three times and arranged in a randomized complete block design (RCBD). The chemical properties of the soil observed were pH, organic C, total N, CEC, exchangeable base (Ca, Mg, K), available P, and available micronutrients (Fe, Mn, Cu, and Zn). The parameters of growth and production observed were plant height, number of tillers, wet weight, and dry weight. The results showed that lime 3 tons/ha (K1) increased soil pH, CEC, exchangeable Ca and Mg and there was P in it. Cow dung increased C-organic, CEC, exchangeable Ca and Mg, and there were P, Fe, and Zn in it. Cow dung, lime, and their interactions had a significant effect on plant height
Keyword: animal feed, cow dung, lime, napier grass, soil fertility

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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