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: Combined use of inorganic and organic fertilizers for tomato yield and fertility of oxisols
Abstrak: Productivity of Oxisols could be improved by addition of organic and inorganic fertilizer. Recently, the use of organic fertilizer is increasing for long term friendly fertility management. The objectives of this research were to determine the appropriate combination of inorganic and organic fertilizer application on tomato yield and to increase nutrient utilization efficiency in the soil, and to determine the effect of combination of inorganic with organic fertilizers on soil chemical properties. The experiment was conducted at Bogor Agricultural University from November, 2009 to July, 2010. The treatments were designed using Factorial experiment in Randomized Complete Block Design (RCBD) with three replications. The treatment consisted of two factors which were rates of inorganic fertilizer [(0-0-0), (2.53 urea- 1.68 SP- 3 KCl), (4.68 urea- 3.12 SP- 6.52 KCl) and (7.2 urea- 4.8 SP- 10 KCl) (g/pot)], and organic fertilizer [0, 200, and 400 (g/pot), (Compost of cow dung, husk and straw in the ratio 1:1:2 by volume) or (Compost of cow dung, husk and peat in the ratio 1:1:2 by volume)]. Replication was treated as block. Data were analyzed using Microsoft Excel, ANOVA using the General Linear Model (GLM) option of Minitab software. The result of the research indicated that combined use of inorganic and organic fertilizers had positive effects on tomato yield and plant nutrient efficiency. The best combination of inorganic fertilizer occurred at lowest doses with organic fertilizer at 200 or 400 g/pot. Combination of inorganic fertilizer at (2.53 urea- 1.68 SP- 3 KCl, g/pot) with straw or peat compost at 400 g/pot resulted in the highest tomato yield than other combinations. Combination of inorganic fertilizer at (2.53 urea - 1.68 SP - 3 KCl, g/pot) with straw compost at 400 g/pot or peat compost at 200 and 400 g/pot resulted in the highest nutrient efficiency. Soil chemical characteristic after harvesting in both organic and inorganic fertilizer treatments had a sound of soil fertility than the soil before planting or fertilizing and increased the use of fertilizers also increased on the soil fertility.
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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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