Judul: The effects of biofertilizer with different drying system and storage period on growth and production of tomato and potato in the field
Abstrak: Biofertilizer is one alternative of fertilizer that is able to increase soil fertility and crop production. The purpose of this research was to investigate the effect of biofertilizer dried by different methods and exposed to different period of storage on nutrient uptake, vegetative growth and production of potato and tomato plant grown in the field. Two experiments were carried out in the field Laboratory of Baltsa Lembang, Bandung. The first experiment was prepared using Randomized Block Design with one factor (biofertilizer application) including i.e (B0) without biofertlizer (control), (B1) liquid biofertilizer, (B2) freezedried biofertilizer without storage, (B3) freezedried biofertilizer with 3 months storage, (B4) centrifuged biofertilizer without storage and (B5) centrifuged biofertilizer with 3 months storage. In this experiment 3 replications (blocks) were applied with total of 18 combination blocks. The second experiment was also prepared using Randomized Block Design with two factors. The first factor was anorganic NPK dosage by (A1) 50% NPK and (A2) 100% NPK and the second factor was biofertilizer application i.e (B0) without biofertlizer (control), (B1) liquid biofertilizer, (B2) freezedried biofertilizer without storage, (B3) freezedried biofertilizer with 3 months storage for tomato, whereas for potato, the factors of (B2) freezedried biofertilizer, (B3) centrifuged biofertilizer were applied. Besides that the plant were fertilized with manuare by about 20 ton/Ha. In this experiment 3 replications (blocks) were applied with total of 24 combination blocks. The results showed that viability of bacterium tended to decline during storage of biofertilizer. The storage of biofertilizer during 3 months did not significantly reduce the effect on growth and production of plant. Application of biofertilizer increased macro and micro nutrient absorption, vegetative growth and plant production. In tomato plant application of biofertilizer increase total macro and micro nutrient as well as plant growth parameters. Plant production also increased as response to biofertilizer by about 112.1% that was indicated by application of B4 for fruit weight per plant. Application of biofertilizer in combination with 100% NPK was almost similar to that of 50% NPK in improving growth and production of plant. All application of biofertilizer significantly reduced disease attack caused by alternaria solani fungus. In potato plant, macro and micro nutrient absorption and root dry weight increased significantly by application of biofertilizer but not on shoot parameters. Plant production, also increased as response to biofertilizer by about 41.6 % indicated by application of centrifuged biofertilizer (B4) for tuber weight per plant and increase plant production per plot by about 79.5 % that was indicated by application of 50 % NPK+ centrifuged biofertilizer (A1B3).
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Judul: The effects of biofertilizer with different drying system and storage period on growth and production of tomato and potato in the field
Abstrak: Pupuk hayati merupakan salah satu alternatif pengganti pupuk anorganik yang dapat meningkatkan kesuburan tanah dan produksi tanaman. Penelitian ini bertujuan menguji efektifitas pupuk hayati hasil berbagai metode pengeringan dan lama penyimpanan untuk meningkatkan serapan hara, produksi tanaman tomat dan kentang di lapangan. Dua percobaan dilakukan di lapangan Laboratorium Balitsa Lembang, Bandung. Percobaan pertama menggunakan Rancangan Acak Kelompok dengan satu faktor (aplikasi pupuk hayati) yaitu (B0) tanpa pupuk hayati (kontrol), (B1) pupuk hayati cair, (B2) pupuk hayati hasil freezedryer tanpa penyimpanan, (B3) pupuk hayati hasil freezedryer dengan 3 bulan penyimpanan, (B4) pupuk hayati hasil sentrifugasi tanpa penyimpanan dan (B5) pupuk hayati hasil sentrifugasi dengan 3 bulan penyimpanan. Percobaan ini dilakukan 3 ulangan dengan total 18 satuan percobaan. Percobaan kedua juga disusun menggunakan Rancangan Acak Kelompok dengan dua faktor. Faktor pertama adalah dosis NPK anorganik yaitu (A1) 50% NPK dan (A2) 100% NPK. Faktor kedua adalah aplikasi pupuk hayati yaitu (B0) tanpa pupuk hayati (kontrol), (B1) pupuk hayati cair, (B2) pupuk hayati hasil freezedryer tanpa penyimpanan, (B3) pupuk hayati hasil freezedryer dengan 3 bulan penyimpanan untuk tomat, sedangkan untuk kentang, (B2) pupuk hayat hasil freezedryer tanpa penyimpanan, (B3) pupuk hayati hasil sentrifugasi tanpa penyimpanan. Selain itu tanaman dipupuk dengan pupuk kandang dosis 20 ton / Ha. Dalam percobaan ini dilakukan 3 ulangan dengan total 24 satuan percobaan. Hasil penelitian menunjukkan bahwa viabilitas bakteri cenderung menurun selama penyimpanan pupuk hayati. Penyimpanan pupuk hayati selama 3 bulan tidak berbeda nyata mengurangi pertumbuhan dan produksi tanaman. Aplikasi pupuk hayati meningkatkan serapan hara makro dan mikro, pertumbuhan vegetatif dan produksi tanaman. Pada tanaman tomat, aplikasi pupuk hayati meningkatkan serapan hara makro dan mikro serta parameter pertumbuhan tanaman. Aplikasi pupuk B4 meningkatkan parameter bobot buah per tanaman sebesar 112.1% dibandingan dengan kontrol. Aplikasi pupuk hayati yang dikombinasikan dengan NPK 100% hampir sama dengan pupuk NPK 50% dalam meningkatkan pertumbuhan dan produksi tanaman. Semua aplikasi pupuk hayati berbeda nyata mengurangi serangan penyakit yang disebabkan oleh cendawan Alternaria solani. Pada tanaman kentang, aplikasi pupuk hayati nyata meningkatkan serapan hara makro dan mikro serta bobot kering akar, kecuali pada parameter tajuk. Produksi tanaman meningkat sebagai respon aplikasi pupuk hayati. Aplikasi pupuk hayati hasil sentrifugasi (B4) meningkatkan bobot umbi per tanaman sebesar 41.6%, sedangkan aplikasi pupuk hayati hasil sentrifugasi + 50% NPK (A1B3) meningkatkan produksi umbi per plot sebesar 79.5%.
Keyword: Fertilizer, Tomato, Potato, Nutrients absorption

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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