Judul: Respon pertumbuhan dan serapan dan hara Cu, Fe, Mn dan Zn pada tanaman kangkung dan bayam dengan pemberian pupuk organik dan anorganik
Abstrak: Mineral nutrients generally categorized as macronutrients and micronutrients. Nutrients Cu, Fe, Mn and Zn were essential for plant because these nutrients have an important role in plant metabolism. The aim of the research was to know the growth response and absorption of micro nutrients Cu, Fe, Mn and Zn of Kangkong and Spinach with organic (cow dung and worm cast) and inorganic fertilizers application (Urea, SP-36, KCI). P1 treatment was the mixed of soil and inorganic fertilizer (Urea 200 kg/ha, SP-36 100 kg/ha, KCI 100 kg/ha for the Kangkong; Urea 200 kg/ha, SP-36 195 kg/ha, and KCI 120 kg/ha for the Spinach). P2 treatment was the mixed of soil and cow dung (30 ton/ha for kangkong and 10 ton/ha for spinach); P3 treatment was the mixed of soil and worm cast of Eisenia foetida (30 ton/ha for kangkong and 10 ton/ha for spinach) and P4 as control. The result showed the given organic and inorganic fertilizers did not affect to all vegetative growth that observed. Nevertheless, plant with organic fertilizer application showed higher average values to all vegetative parameters that observed compared to inorganic fertilizer or control plants. Plant with organic fertilizer treatment also showed higher absorption of macronutrients and micronutrients compared to inorganic and control treatment. Kangkong plants with cow dung treatment showed absorption of micronutrients Fe, Mn, Zn and Cu respectively 511.8 ppm, 123.1 ppm, 93.2 ppm, and 13.4 ppm. Spinach plants with cow dung treatment showed absorption of Fe, Mn, Zn and Cu respectively 354.4 ppm, 104.7 ppm, 102.7 ppm and 12.8 ppm. Control plant showed low average values to all vegetative parameters that observed.
Keyword: 

Judul: Growth and Yield Response of Kangkong (Ipomoea reptans Poir) to the Aplications of Kascing, Bioboost, and Their Residues, Growth and Yield Response of Kangkong (Ipomoea reptans Poir) to the Aplications of Kascing, Bioboost, and Their Residues
Abstrak: Penelitian ini bertujuan untuk mengetahui respon pertumbuhan dan hasil kangkung terhadap pemupukan kascing dan bioboost beserta residu keduanya. Penelitian ini menggunakan Rancangan Kelompok Lengkap Teracak Faktorial. Faktor pertama adalah pemupukan kascing (K) dan residunya (RK), yaitu tanpa kascing (K0 dan RK0), kascing 300 g per lubang tanam (K1 dan RK1), dan kascing 450 g per lubang tanam (K2 dan RK2). Faktor kedua adalah pemupukan bioboost (B) dan residunya (RB), yaitu tanpa bioboost (B0 dan RB0), 2 l /ha (B1 dan RB1), 4 l/ha (B2 dan RB2), dan 6l/ha (B3 dan RB3). Kedua faktor diuji terhadap kontrol negatif (tanpa pemupukan) dan kontrol positif (pemupukan anorganik susulan) setiap perlakuan diulang sebanyak tiga kali sehingga seluruhnya terdapat 39 satuan percobaan dengan luas masing-masing petakan 1,5 m2. Penanaman dilakukan sebanyak dua kali. Penanaman kedua dimaksudkan untuk mengamati residual effect kedua faktor. Hasil penelitian ini menunjukkan kangkung terbaik terdapat pada interaksi 450 g kascing per lubang tanam dan 6 liter bioboost per hektar dengan potensi hasil mencapai 23,67 ton per hektar pada penanaman pertama dan 17,73 ton per hektar pada penanaman kedua yang memanfaatkan residu pemberian kascing dan bioboost sehingga tidak perlu melakukan pemupukan pada penanaman kedua., This study aims to determine the growth response and yield of kangkong to vermicompost and bioboost fertilization and their residues. This study used a Factorial Randomized Complete Group Design. The first factor was fertilization with vermicompost (K) and its residue (RK), ie without vermicompost (K0 and RK0), 300 g vermicompost per planting hole (K1 and RK1), and 450 g vermicompost per planting hole (K2 and RK2). The second factor was fertilization with bioboost (B) and residue (RB), namely without bioboost (B0 and RB0), 2 l/ha (B1 and RB1), 4 l/ha (B2 and RB2), and 6 l/ha (B3 and RB2). RB3). Both factors were tested against negative control (without fertilization) and positive control (follow-up inorganic fertilization). Each treatment was repeated three times so that in total there were 39 experimental units with an area of 1,5 m2 each. Planting was carried out twice. The second planting is intended to observe the residual effect of the two factors. The results of this study showed that the best kangkong was found in the interaction of 450 g of vermicompost per planting hole and 6 liters of bioboost per hectare with a potential yield of 23, 67 tonnes per hectare in the first planting and 17,73 tonnes per hectare in the second planting using residues of vermicompost and bioboost so there is no need to fertilize the second planting.
Keyword: dose, inorganic, mandailing natal, organic, yield potential, anorganik, dosis, mandailing natal, organik, potensi hasil

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.
Keyword: