Judul: Effects of shade at different stages of plant development and plant population on growth, yield, and yield components of soybean [Glycine max (L.) Merr.]
Abstrak: Dua percobaan lapangan dilakukan pada tanah latosol di kebun Percobaan IPB, Babakan Darmaga, Bogor, Indonesia selama musim kemarau 1977 dan musim kemarau 1978. Percobaan pertama bertujuan mengetahui pengaruh naungan yang diberikan pada berbagai tahap perkembangan terhadap pertumbuhan, hasil biji, dan komponen hasil tanaman kedelai varietas Orba dan galur harapan No. 1667. Percobaan kedua bertujuan mengetahui populasi yang tepat pada keadaan ternaungi untuk memperoleh hasil biji tertinggi pada tanaman kedelai.
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Judul: The Effect of Chemical Fertilizer Dosage and Type of Biofertilizer on the Growth and Production of Soybean (Glycine max L.)
Abstrak: Kedelai (Glycine max L.) adalah komoditas pangan yang banyak dikonsumsi oleh masyarakat Indonesia. Tingginya kebutuhan kedelai dalam negeri membuat usaha untuk meningkatkan produksi sangat dibutuhkan. Salah satu caranya dengan meningkatkan kesuburan tanah melalui pemupukan. Penelitian ini bertujuan mengetahui pengaruh dosis pupuk kimia dan penambahan pupuk hayati terhadap pertumbuhan dan produksi tanaman kedelai. Penelitian dilakukan di Kebun Percobaan IPB Sawah Baru dari bulan November 2023 hingga Maret 2024. Percobaan menggunakan rancangan Split-Plot RKLT dengan dua faktor yaitu faktor pupuk kimia sebagai petak utama dengan dua taraf, yaitu 50% (K1) dan 100% (K2) dosis dan faktor pupuk hayati sebagai anak petak dengan 5 taraf, yaitu tidak diberi pupuk hayati (H0), pupuk hayati jenis 1 (H1), pupuk hayati jenis 2 (H2), pupuk hayati jenis 3 (H3) dan pupuk hayati jenis 4 (H4). Perlakuan 100% dosis pupuk kimia dapat meningkatkan jumlah daun 8 MST, jumlah cabang 8-10 MST, nilai kehijauan daun, nilai indeks luas daun, bobot brangkasan, jumlah polong dan biji per tanaman, bobot biji per tanaman dan bobot 100 butir. Sementara pupuk hayati jenis 4 dapat meningkatkan jumlah cabang 6-8 MST, jumlah polong dan biji per tanaman, serta indeks luas daun tetapi tidak berbeda nyata dengan pupuk hayati jenis 1,2,3, dan kontrol., Soybeans (Glycine max L.) are a commodity that is widely consumed by Indonesian people. The high level of demand for soybeans in Indonesia make efforts to increase production is necessary. One of the ways to increase soil fertility through fertilizing with biological fertilizer. This research aims to determine the effect of chemical fertilizer doses and the addition of biological fertilizer on the growth and production of soybean plants. The research was conducted at the IPB Sawah Baru Experimental station from November 2023 to March 2024. The experiment used a Split-Plot RCBD design with two factors, namely the chemical fertilizer factor as the main plot with two levels, namely 50% (K1) and 100% (K2) of the dose. optimum and biofertilizer factors as sub-plots with 5 levels, namely no biofertilizer (H0), type 1 biofertilizer (H1), type 2 biofertilizer (H2), type 3 biofertilizer (H3) and type 4 biofertilizer (H4). Treatment 100% dose with chemical fertilizer can increase the number of leaves 8 WAP, number of branches 8-10 WAP, leaf greenness value, leaf area index, dry weight of stover, number of pods per plant, number of seeds per plant, weight of seeds per plant, number of 100 grains. Type 4 biological fertilizer can increase the number of branches 6-10 WAP, number of pods per plant, leaf area index, and number of seeds per soybean plant but is not significantly different from the type 1,2,3 biofertilizer and control.
Keyword: Pupuk hayati, Produksi, detap 1

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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