Judul: Respon Tanaman Cabai Merah terhadap Arah Baris Tanam yang Berbeda
Abstrak: Seloka IPB is big red chili variety of a hybrid result between IPB C2 and IPB C5. This chili has harvest ageof 62 to 86 days after planting, has high productivity and is adaptedto lowland with an altitude of 100-250 masl. While Kopay chili variety is curly red chili from Payakumbuh, West Sumatra. Kopayhas harvest age of 80- 85 days after planting (in lowland) and 90-95 days after planting (in highland), has a high productivity, and has fruitslength of 30-35 cm. This research was aimed to analyze the effect of South-North (SN) and East-West (EW) row planting on radiation balance and on biomass production. The research was conducted from 23 February to 25 June 2014 in Climatological Station Class 1 BMKG Dramaga Bogor. The results showed that row planting direction significantly affected the number of leaves and total dry weight. Total global radiation above the plant canopy was 1712 MJ m-2. Interception of radiation in row direction of EW and NS amounted to 123.8 MJ m-2 and 132.7 MJ m-2, respectively. Radiation use efficiency (RUE) in row direction of NSwas between1.23 g/MJ (minimum) and 1.41 g/MJ (maximum); while in row direction of EWwas between 1.02 g / MJ (minimum) and 1.27 g/MJ (maximum). The row direction of NS was able to intercept radiation 7% larger than that of EW. In addition, the row direction of NSalso produced 24% more plant total biomass than the row direction of EW. It is concluded that planting inNSrow direction could utilize solar radiation more efficientlyand produce more biomass.
Keyword: Bogor Agricultural University (IPB), total biomass, RUE, radiation use efficiency, radiation balance, kopay, Seloka IPB

Judul: Evaluasi Lahan untuk Cabai Merah Besar (Capsicum annuum L.) di Kebun Pendidikan Cikabayan IPB Dramaga
Abstrak: Pengoptimalan potensi produksi cabai merah besar di Kebun Pendidikan Cikabayan IPB Dramaga perlu mempertimbangkan kelas kesesuaian lahan. Budidaya cabai merah di daerah ini dihadapkan pada tantangan berupa curah hujan yang tinggi dan jenis tanah yang secara kimia masih memerlukan perbaikan. Penelitian bertujuan mendapatkan kelas kesesuaian lahan berdasarkan konsep FAO dengan kriteria BBSDLP serta mendapatkan data dan fakta keterkaitan antara pertumbuhan dan produktivitas cabai merah besar. Tujuan lain dari penelitian ini adalah tersedianya informasi kelayakan usahatani. Metode yang digunakan adalah evaluasi lahan sesuai konsep FAO dengan kriteria BBSDLP serta evaluasi lahan secara langsung sesuai praktik budidaya yang dilakukan oleh petani. Kesesuaian lahan aktual cabai merah adalah S3 dengan faktor pembatas berupa curah hujan yang terlalu tinggi, retensi hara (KB dan pH) yang tergolong kurang, serta ketersediaan P dan K yang rendah. Hasil evaluasi lahan secara langsung berdasarkan produksi yang dibandingkan dengan produksi optimal pada umur 4 bulan bernilai S3 dan pada asumsi umur hingga 7 bulan bernilai S2. Hasil evaluasi lahan secara langsung berdasarkan produksi yang dibandingkan dengan potensi produksi varietas pada umur 4 bulan maupun hingga 7 bulan bernilai N. Pertumbuhan cabai merah besar sesuai dengan kurva pertumbuhan sigmoid dan secara ekonomi layak diusahakan (R/C ratio > 1) baik pada umur 4 bulan maupun asumsi hingga umur 7 bulan., Optimation of red chili production potential in the Cikabayan Education Farm of IPB Dramaga needs to consider land suitability. Red chili cultivation in this area is faced with challenges of high rainfall and soil type which chemically still requires improvement. This study aims to obtain land suitability classes based on FAO concept with CALRRD criteria and to obtain data and facts on the relationship between growth and productivity of red chili. Another aims of this study is the availability of farming feasibility information. The methods used were land evaluation based on FAO concept with CALRRD criteria and direct land evaluation based on farmer’s cultivation practice. The actual land suitability of red chili is S3 with high rainfall, low nutrient retention (BS and pH), and less availability of P and K as limiting factors. The results of direct land evaluation based on production compared to optimal production at the age of 4 months was S3 and the assumed age of up to 7 months was S2. The results of direct land evaluation based on production compared to variety of production potential at the age of 4 months and up to 7 months were N. The growth of red chili corresponds to the sigmoid growth curve and economically feasible (R/C ratio>1) either at the age of 4 months or the assumed age of up to 7 months.
Keyword: growth, production, rainfall, R/C ratio, soil

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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