Judul: Pengaruh Pemupukan Nitrogen Terhadap Fisiologi Dan Karakter Laju Pengisian Biji Beberapa Varietas Kedelai
Abstrak: Soybean is one of the main agricultural commodities in Indonesia. It seen from the high national demand. High demand is not accompanied by high national production, as a consequence the volume of imports is still high to meet national requirment. The large number of imports must be responded with various efforts to increase the productivity of soybean plants, one of them is by optimizing fertilization technology through studying the important role of essential nutrients in order to get optimal crop production. Nitrogen is needed by plants in large quantities. N affects the rate of single leaf photosynthetic capacity associated with size of leaf area. The rate of photosynthesis increases the production of dry matter plants, dry matter plants will be a source for seed development. Productivity is the yield of seeds per unit area of land. Seed weight is affected by the rate of seed filling per unit time during the seed filling period. This study aims to see how the characteristics of seed filling rate of varieties that have different seed sizes and the effect of N in the rate of seed fillings of plants. The study was conducted from July to November 2019 in the Cikabayan experimental station, Bogor. The experimental design used was a randomized complete group design (RCBD) with a dose factor of urea (0 and 50 kg ha-1) and soybean varieties with different seed sizes (Tanggamus, Anjasmoro, Grobogan, Biosoy 1) with two replications. The laboratories used were the Postharvest Laboratory of the Department of AGH IPB and PAU FATETA LAB IPB. The seed filling rate for each variety has a pattern that is increased towards the end of the filling phase except for Biosoy 1. Increased seed filling rate is followed by remobilization of assimilate (dry matter) and N from the canopy to the seeds. Dry matter remobilization has a positive correlation with N which is remobiliated from the canopy. Seed size does not have a correlation to the rate of seed filling, although at the beginning of filling each seed has a significantly different rate. N dose given to plants does not significantly influence the rate of seed filling. N dose influences the amount of N to be mobilized but does not affect the dry matter that could mobilized.
Keyword: N translocation, net assimilation rate, non-structural carbohydrates, rate of growth, seed filling rate

Judul: Growth, Physiological and Production Responses of Two Soybean Varieties to Difference N Dossages
Abstrak: Pemupukan diperlukan untuk menunjang pertumbuhan tanaman kedelai. Nitrogen merupakan salah satu jenis pupuk yang dibutuhkan kedelai dalam jumlah yang cukup banyak. Ketersediaan senyawa nitrogen di dalam tanah sangat terbatas karena senyawa ini memiliki sifat mudah hilang melalui pencucian maupun penguapan. Pemberian nitrogen pada waktu yang berbeda dapat berpengaruh terhadap produksi dan kualitas biji kedelai. Tujuan penelitian ini adalah untuk memperoleh informasi tentang respon morfologi dan fisiologi dari dua varietas kedelai terhadap pemberian N. Penelitian ini dilaksanakan di Kebun Percobaan Cikabayan, Institut Pertanian Bogor, Dramaga, Kabupaten Bogor. Penelitian ini menggunakan rancangan faktorial berupa rancangan kelompok lengkap teracak 2 faktor yaitu 2 varietas kedelai yang terdiri dari Tanggamus dan Biosoy 1 dengan 4 kombinasi dosis pupuk N di antaranya N0, N1, N2, dan N3 yang diulang sebanyak 2 ulangan. Dosis pupuk N yang digunakan sebanyak 11,5 kg ha-1. Hasil penelitian menunjukkan bahwa morfologi dan fisiologi dari kedua varietas kedelai yang digunakan tidak responsif terhadap adanya pemberian pupuk N, baik dosis maupun interval aplikasinya. Karakter morfologi tanaman lebih dipengaruhi oleh genetik dan kondisi lingkungan tumbuh dari masing-masing varietas yang digunakan, begitupun dengan karakter fisiologinya, sedangkan interaksi antara varietas dengan pemberian pupuk N tidak menunjukkan respon yang signifikan terhadap hasil tanaman yang didapatkan., Fertilization is needed to support the growth of soybean plants. Nitrogen is a type of fertilizer that is needed by soybeans in considerable amounts. The availability of nitrogen compounds in the soil is very limited because these compounds are easily lost through leaching or evaporation. Aplication of nitrogen at different times is able to affect the production and quality of soybean seeds. The purpose of this study was to attain information about the morphology and physiology responses from two soybean varieties to the supply of N. This research was conducted at the Cikabayan Experimental Station, IPB University, Dramaga, Bogor Regency. This study used a factorial design in the form of a randomized complete block design with 2 factors, namely 2 soybean varieties consisting of Tanggamus and Biosoy 1 and 4 combinations of N fertilizer doses that were N0, N1, N2 and N3 with 2 replications. The dosage of fertilizer used was 11,5 kg ha-1. The results showed that the morphology and physiology of the two soybean varieties used were not responsive to the application of N fertilizer, both the dosage and the application interval. The morphological characters of the plants are more affected by the genetic and environmental conditions of each variety used, as well as the physiological characters, while the interactions between the varieties and the application of N fertilizers did not show a significant response to the yields.
Keyword: genetik, hasil tanaman, kualitas biji, nitrogen

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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