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: Simulasi pertumbuhan untuk menganalisis pengaruh jadwal  tanam terhadap produktivitas budidaya Cabai Merah (Capsicum  annuum L.) di Kabupaten Nganjuk
Abstrak: Tanaman cabai merah (Capsicum annuum L.) merupakan tanaman yang memiliki nilai ekonomis yang tinggi, namun jumlah produksi cabai merah yang fluktuatif di tingkat pasar, dapat mengakibatkan jumlah ketersediaan cabai merah yang tidak mencukupi. Sebagai solusi dibutuhkannya pendugaan jumlah hasil panen cabai merah di sepanjang tahun. Penelitian ini dilakukan untuk membuat simulasi model tanaman cabai merah yang dapat mensimulasikan proses pertumbuhan dan perkembangan tanaman cabai merah. Simulasi model tanaman cabai merah ini menggunakan parameter cuaca harian, yang meliputi: suhu maksimum, suhu minimum, suhu rata-rata, kelembaban, kecepatan angin, curah hujan, radiasi matahari, dan evaporasi potensial. Keluaran dari simulasi model ini adalah komponen biomassa harian berupa organ buah panen cabai merah (kg/ha). Ketelitian pada Kecamatan Gondang sebesar 65.3 %, Kecamatan Pace sebesar 83.1 %, dan ketelitian terhadap data rata-rata panen sebesar 93.2%., Red chilies (Capsicum annuum L.) are plants with a high economic value, but the red chilies production in market is fluctuative, so it makes the availability of red chilies is inadequate. As a solution, an estimation of the number of red chiles production in a year is necessary. This research was conducted to make a red chilies model simulation that could simulate the growth and development processes of red chilies. This red chilies model simulation used daily weather parameters including: maximum temperature, minimum temperature, average temperature, humidity, wind speed, rainfall, sun radiation, and potential evaporation. The outputs of this model simulation were daily biomass components such as red chilies crops organ (kg/ha). Precision value in Gondang Sub-district was 65.3%, precision value in Pace Sub-district was 83.1%, and precision value of average red chilies production was 93.2%.
Keyword: biomassa, cabai merah, cuaca harian, simulasi model

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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