Judul: Pengaruh Fosfor dan Silikon terhadap Pertumbuhan dan Produksi Padi Gogo (Oryza sativa L.) Varietas Situ Patenggang pada Latosol Dramaga
Abstrak: Phosphorus (P) and Silicon (Si) deficiencies were two kinds of constraint of upland rice production. Latosol is one type of soil that is poor in nutrients, especially P and Si, acidic reaction due to intensively weathering and leaching. Greenhouse trial has conducted at experimental station of Cikabayan, Dramaga, and Chemistry and Fertility Laboratory of Soil, Department of Soil Science and Land Resources, Bogor Agricultural University. Materials were used at this study are: a soil material (Dramaga’s Latosol), upland rice seed cultivar Situ Patenggang, SP-36, Na2SiO3, KNO3, Urea, KCl. Research includes: Si liquid fertilizer formulation, and trial the effect of fertilizers of P, Si and Si application method to the growth and yield of upland rice with a completely randomized factorial design. Results of the trial showed that treated of P increasing the growth and yield of upland rice (plant height, number of tillers, dry weight of grain and straw dry weight) as well as increasing the levels of P straw. Treated of Silicon has increasing the growth and yield of upland rice (plant height, number of tillers, number of panicle, dry weight of grain and straw dry weight) and increasing the Si content in the straw and husk. The interaction effect was only found on the treated of P and the Si fertilizer application methods (T) on the variable of dry weight of grain and treated of Si and T on the variable of dry weight of straw. Silicon fertilizer can be applied through the leaves with spraying. Silicon fertilizer application via the soil slightly more effective than through the leaves.
Keyword: upland rice, phosphorus, silicon

Judul: Pengaruh Trass dan Pupuk Fosfor terhadap Pertumbuhan dan Produksi Padi Gogo serta Perubahan Sifat Kimia pada Latosol Gunung Sindur
Abstrak: The high conversion of rice fields to non-agricultural fields have reduced rice production, so it needs the utilization of dry land for paddy cultivation. Latosol is one type of nutrient-poor soils, especially Silica (Si) and phosphorus (P), and generally it is acidic due to further weathering and intensive leaching. This study aimed to determine the effect of Trass and Phosphorus (P) on yield and nutrient uptake of rice plants, as well as changes in the chemical properties of Mount Sindur’s Latosol. This study was a greenhouse experiment conducted in Cikabayan University Farm, Bogor Agricultural University. Soil and plant analysis carried out in the Laboratory of Chemistry and Soil Fertility, Department of Soil Science and Land Resources, Faculty of Agriculture, Bogor Agricultural University. This study took place from October 2012 to April 2013. This experiment used a completely randomized design (CRD) with 2 factors. As the first factor was Trass doses (0 tonnes / ha (T0), 2.37 tonnes / ha (T1), 4.74 tonnes / ha (T2), and 7.11 tons / ha (T3). Second factor was P fertilizer (0 ppm P (P0), 50 ppm P (P1), and 100 ppm (P2). Experiment was repeated 3 times so that there were 36 experimental units. Results showed that there was no interaction effect between Trass and phosphorus in all observed variables. But as a single factor, Trass significantly affect to increase the number of productive tillers in treatment T3 equal to 17.5%, while the increasing amount of soil available-P influence T1, T2, and T3 treatments, respectively for 25%, 62.5, and 149.4%. Further, there was an increase in P-uptake effect on T1, T2, and T3 treatments, respectively for 4.5%, 9.5%, and 24.3%. Moreover, P Fertilizer application was significantly affect the increasing of plant height on P1 and P2 treatments, respectively for 17:45% and 17.6%, number of tillers earnings 3.8% and 20%, biomass weight for 108.4% and 159.7%, and the grain weight for 47.9% and 52.1%, while the increase effect on Si-uptake of P1 and P2 treatments, respectively for 62.07% and 87 %, and decrease the available-Si, respectively for 9.1% and 22.5%.
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Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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