Judul: Addition of Plant Growth Promoting Rhizobacteria to Improve the Quality of Organic Fertilizer, Nutrient Uptake, Growth and Yield of Upland Rice and Maize
Abstrak: Biofertilizer is one of the alternative fertilizers that can increase nutrient uptake, plant growth and production. The purpose of this research was to evaluate the quality of organic fertilizer (compost) enriched with bofertilizer and its effect on nutrient uptake, growth and yield of upland rice and maize. This experiment was conducted using a Randomized Block Design with two factors of treatment. The first factor was organic fertilizer that consist of three levels: compost without biofertilizer as a control, compost enriched with biofertilizer, compost and biofertilizer applied separately on the day of planting. The second factor was the anorganic fertilizer consisting 2 levels: 50% and 100% of recommended doses. The upland rice var Situbagendit and maize var Bisma were grown on the field condition. The bacteria used as biofertilizer were Bacillus subtilis strain HU48, Pseudomonas beteli strain ATCC1986IT, Azotobacter sp. strain HY1141, dan Azospirillum sp. strain NS01. The compost enriched with biofertilizer had the best effect on most variables observed including nutriet uptake, growth, biomass, and production of both crops. This enriched compost increased macro and micro elements uptake of upland rice and maize. This treatment increased the production of upland rice up to 73% while the maize production increased up to 38%. Anorganic fertilizer increased significantly the macro nutrient uptake in upland rice but not in maize. In comparison with 50% dose of anorganic fertilizer, 100% dose anorganic fertilizer increased the plant growth and yield of upland rice and maize. However, this increase was not significant. The best treatment was showed by compost enriched with biofertilizer that was combined with 100% anorganic fertilizer. This treatment increased grain weight up to 109,28% of upland rice, and seed weight up to 41,18% of maize compared to control.
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Judul: Respon Fisiologi Tanaman Jagung dan Cabai Terhadap Aplikasi Pupuk Organik yang Diperkaya dengan Pupuk Hayati pada Dua Lokasi Pengujian yang Berbeda.
Abstrak: It was known that biofertilizer can improve plant growth and production. The aim of this research was to study the influence of organic fertilizer enriched by biofertilizer on maize (Zea mays L.) and chili (Capsicum annum L.) planted in Bogor (West Java) and Kubu Raya (West Kalimantan). This research was conducted by using randomized block design with two factors. The first factor was the NPK fertilizer doses, which were 0%, 50%, and 100% of recommended dose. The second factor was different type of organic fertilizers, which were without compost, compost, and compost enriched with biofertilizer. Growth and production of both maize and chili increased in Kubu Raya as well as in Bogor. In combining with enriched compost, there was no significally different effect between NPK dose of 50% and 100%. The result showed that enriched compost was able to reduce the use of NPK fertilizer up to 50%. Production of maize in Kubu Raya was higher than that of in Bogor, while the chili production was higher in Bogor than that of Kubu Raya. Enriched compost affected leaf chlorophyll content of maize in Kubu Raya and Bogor, but it had no effect on vitamin C content of chili and total sugar content of maize planted in both locations.
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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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