Judul: Pertumbuhan dan Produksi Kacang Bogor (Vigna subterranea (L.) Verdcourt) dengan Pelbagai Dosis dan Cara Pemberian Pupuk Kandang Ayam
Abstrak: This research aimed to get optimal rate of manure and proper manure application to increase crop production of bambara groundnut. The research was conducted from February to June 2014 at IPB experimental field. The experiment used factorial in randomized complete block design with two factors and three replications. The first factor was rates of chicken manure with four i.e. 0, 5, 10, and 15 tons ha-1. The second factor was 2 application methods of manure i.e. spread over the soil surface and put in planting row. Growth and production of bambara groundnut was insignificantly affected by neither manure rates nor manure applicaton methods. Although there was not significant effect of manure rates, there was indication that the highest yield (number of pods per plant) of bambara groundnut could be achieved with the addition of 6.8 tons manure ha-1. Bambara groundnut crop were heavily infected by desease at 7 weeks after planting, this might have resulted in insignificant effect of treatments to all variables.
Keyword: crop substitution, chicken manure, legume

Judul: Determination of N, P, and K Fertilizer Optimum Rates for Bambara Groundnut (Vigna subterranea [L.] Verdcourt).
Abstrak: Bambara groundnut is the one of nuts that have a high potential to be developed. Bambara groundnut has the best drought resistance among other nuts, but it also has another advantage that is tolerant of unfertile soils. The average yield of dry pod weight from agricultural fields in Indonesia were under 4 ton ha-1, that value is still low. Therefore, must be an efforts to improve Bambara groundnut production. Fertilization is the key efforts for increased the productivity of Bambara groundnut. The objective of the research was to determine optimum rate of N, P, and K fertilizer for Bambara groundnut (Vigna subterranea [L.] Verdcourt) production. Three experiments were conducted at Cikarawang Farm, Dramaga, Bogor from March to July 2013. Each experiment tested different rates of N or P or K fertilizer with randomized compeletely block design and three replications. The fertilizer rates were 0, 50, 100, 150, and 200% of reference rate (100% N = 45 kg N ha-1, 100% P = 54 kg P2O5 ha-1, 100% K = 45 kg K2O ha-1). On all experiments, 100% P, 100% K, and 30% N were applied at planting, while 70% N was applied at 5 week after planting. Plot size was 6 m x 3 m, with plant spacing of 60 cm x 30 cm. Harvesting were conducted at 16 week after planting. The result showed that leaf P content increased linearly with N fertilizer application. Leaf N content decreased linearly with P fertilizer application. Root fresh weight, seed N content, and shoot dry weight quadratically increased with K fertilizer application. Because of very limited numbers of variable that were significantly affected by the treatment, optimum rate of N, P, K fertilization can not be determined through multi nutrient response technique in these experiments. Only the optimum rate of K fertilizer that can be determined with the range of 51.48-69.78 kg K2O ha-1. Based on production, the highest productivity estimation were 30.91 kg N ha-1, 54.81 kg P2O5 ha-1, and 46.85 kg K2O ha-1 although not significant.
Keyword: multi nutrient response, NPK fertilization

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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