Judul: Optimasi Tillage Area untuk Penanaman Jagung Manis (Zea mays saccharata Sturt) pada Sistem Olah Tanah Minimum dengan Biomulsa Arachis pintoi Krap. & Greg.
Abstrak: Penggunaan biomulsa Arachis pintoi merupakan salah satu teknik budidaya yang memanipulasi lingkungan untuk pertumbuhan dan perkembangan tanaman. Mulsa Arachis pintoi digunakan antara lain untuk mengembalikan unsur hara tanah terutama di lahan kritis yang miskin kandungan unsur hara dan menekan pertumbuhan gulma. Penelitian dilaksanakan pada bulan Desember 2016-Maret 2017 di Cikarawang, Dramaga, Bogor. Penelitian ini dilakukan untuk mempelajari pengaruh dari pengolahan tanah minimum dan penanaman Arachis pintoi sebagai biomulsa terhadap pertumbuhan, produksi, kualitas hasil pada pertanaman jagung manis serta mencari tillage area yang optimum. Penelitian ini menggunakan rancangan kelompok lengkap teracak (RKLT) satu faktor dengan tiga ulangan. Ukuran tillage area yang digunakan adalah 0 cm (zero tillage), 8 cm, 16 cm, 24 cm, 32 cm dan tanpa biomulsa (conventional tillage) sebagai pembanding. Hasil penelitian menunjukkan penanaman Arachis pintoi sebagai biomulsa pada pertanaman jagung manis secara nyata menekan pertumbuhan dan produksi jagung manis apabila Arachis pintoi dibiarkan menutup area pertanaman tanpa pengolahan tanah. Dengan sedikit pengolahan tanah di area tanam jagung manis yaitu berkisar 16 cm dapat meningkatkan produksi jagung manis dibandingkan dengan sistem pengolahan tanah konvensional. Hasil lain dari penelitian ini adalah penggunaan Arachis pintoi selama tiga tahun meningkatkan kandungan C organik, kandungan N organik, dan P2O5.
Keyword: Arachis pintoi, pertumbuhan, produksi, tillage area

Judul: Kajian Agronomi Pemanfaatan Biomulsa Kacang Hias (Arachis pintoi) pada Budidaya Jagung Manis (Zea mays saccharata Strurt.) di Lahan Kering
Abstrak: The aim of the experiment was to observe the effect of the utilization of legum cover crop Arachis pintoi as bio-mulch on sweet corn production (Zea mays saccharata Sturt) compared with Centrosema pubescens and Calopogonium mucunoides. The experiment was held at Cikabayan Eksperimental Field, Bogor in February-September 2013. Randomized completey block design (RCBD) was used in this experiment with a single factor and three repitions. The factor is the difference of mulch variety that consist of control (natural vegetation with weeding), natural vegetation (without weeding), plastic mulch, A. pintoi, C. pubescens, and C. mucunoides. The use of A. pintoi bio-mulch influenced weeds variety replacement that grown in the treatment field. The treatment of A. pintoi is more effective to decrease the growth of grass weeds than that of C. pubescens and C. mucunoides. The treatment of A. pintoi bio-mulch increased the content of C-Organik, N-Total, and K2O in the soil. Based on the result, the difference of mulch variety showed a significant effect on all of observed sweet corn characters, except cob long and circle. The result also showed no significant difference among the treatments of A. pintoi, C. pubescens, and C. mucunoides on sweet corn production. The treatment of plastic mulch showed a higher rate than another treatment in increasing sweet corn production.
Keyword: production, weeds, bio-mulch, Arachis pintoi

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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