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 fosfor dan jenis serta cara pemberian silikon terhadap pertumbuhan padi gogo varietas Cirata pada podsolik Jasinga
Abstrak: Padi gogo merupakan alternatif sumber beras potensial mengingat kontribusi terhadap produksi beras nasional masih rendah (sekitar 5,5%) dan tingkat produktivitas rata-rata 2,4 ton/ha, (Toha et al., 2005). Di lain pihak potensi lahan kering untuk tanaman padi gogo masih tersedia sangat luas. Podsolik (Ultisol) merupakan bagian lahan kering terluas kedua di Indonesia dengan berbagai permasalahannya terutama berkaitan dengan kemasaman dan kesuburannya Serangkain percobaan telah dilakukan dengan menggunakan Rancangan Acak Lengkap Faktorial, 18 perlakuan dengan tiga kali ulangan, dengan menggunakan Podsolik Jasinga, sebagai media tanam. Perlakuan P sebagai faktor pertama, dalam bentuk SP-36, diberikan dalam tiga taraf yaitu tanpa P (PO), 1.9 g (P1) dan 3.8 g (P2) per pot. Silikon dalam bentuk Waterglass (Na2SiO3) sebagai faktor kedua diberikan dalam tiga taraf yaitu tanpa Si (Si0), Si murni (Si) (0.8.g Si/pot), dan Si-N (Si-N) (0.8 g Si/pot dan 10.6 g N/pot). Faktor ketiga yaitu cara pemberian Silikon (T) yang diberikan dalam dua cara yaitu TI (lewat daun) dan T2 (lewat tanah). Sebagai tanaman indikator digunakan padi varietas Cirata. Percobaan ini dilakukan dari bulan April 2006 sampai dengan Agustus 2006 di Rumah kaca University Farm IPB di Cikabayan dan Laboratorium Kimia dan Kesuburan, Departemen Ilmu Tanah dan Sumberdaya Lahan, IPB. Penelitian ini bertujuan melihat pengaruh Fosfor dan Silikon terhadap pertumbuhan, dan kadar N, P, dan K Padi Gogo pada Podsolik Jasinga. Hasil percobaan menunjukkan bahwa pemberian fosfor berpengaruh nyata meningkatkan terhadap tinggi tanaman, jumlah tanaman, bobot kering gabah dan meningkatkan kadar N, P, dan K, daun bendera. Pemberian Si berpengaruh pada jum;ah malai dan bobot kering gabah. Perlakuan kombinasi antara P dan Si berpengaruh nyata meningkatkan tinggi tanaman tetapi tidak berpengaruh nyata terhadap variabel pertumbuhan lainnya. Perlakuan kombinasi antara Si dan T berpengaruh negatif terhadap tinggi tanaman dan bobot kering gabah. Hasil penelitian menunjukkan bahwa cara pemberian pupuk Si lewat daun (T1) dan lewat tanah (T2) berpengaruh terhadap tinggi tanaman dan bobot kering tanaman. Cara pemberian Si lewat tanah nyata lebih tinggi pengaruhnya terhadap tinggi tanaman dan bobot kering tanaman dibandingkan cara pemberian Si lewat daun.
Keyword: Silikon, Fosfor, Tanaman padi gogo

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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