Judul: Pengaruh pemberian silikon pada tiga kelengasan tanah terhadap pertumbuhan dan produksi padi (Oryza sativa, L.)
Abstrak: Penelitian ini berbentuk percobaan pot, dilakukan di rumah kaca Agronomi IPB, dengan mengunakan tanah Podzolik Merah Kuning yang diambil dari Baturaja, Sumatra Selatan. Sebagai tanaman penunjuk digunakan padi gogo varietas C22. Rancangan yang digunakan adalah rancangan petak terpisah. Kelengasan tanah setengah kapasitas lapang, kapasitas lapang, dan digenangi sebagai anak petak. Pemberian silikon sebanyak 0, 84, 168, dan 336 kg Si02 tiap hektar sebagai anak petak. Penelitian ini bertujuan untuk mempelari sejauh mana pemberian silikon mempengaruhi pertumbuhan dan produksi, bila tanaman ditumbuhkan pada kelengasan tanah yang berbeda. Selanjutnya ingin pula dilihat hubungan antarapemberian silikon dengan kandungan Si02, N, P, K, Ca dan Mg tanaman. Kelengasan tanah nyata berpengaruh terhadap semua parameter yang diamati, kecuali terhadap besarnya sudut daun. Pertumbuhan tanaman padi varietas C22 yang tercermin dari tinggi tanaman, luas daun, jumlah anakan, dan bobot kering tanaman lebih baik, serta produksi lebih tinggi, bila kelengasan tanah dipertahankan pada kapasitas lapang, dibandingkan dengan bila kelengasan tanah diturunkan hingga setengah kapasitas lapang atau dinaikkan hingga tergenang.
Keyword: Cereal;, Upland rice;, Clodosporium spp;, Rice blast;, Bogor Agricultural University;

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: 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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