Judul: Growth of Water Spinach and Spinach Due to the Application of Inorganic Liquid Fertilizer in the Hydroponic System
Abstrak: Hidroponik adalah salah satu metode alternatif dalam budidaya sayur, metode ini tidak memerlukan area yang luas. Produksi dari hidroponik dapat ditingkatkan dengan pemenuhan nutrisi yang tepat. Penelitian ini bertujuan menganalisis efek penambahan pupuk anorganik cair pada larutan hara AB mix terhadap pertumbuhan tanaman kangkung dan bayam. Rancangan penelitian yang digunakan adalah Rancangan Acak Kelompok. Perlakuan yang diamati adalah konsentrasi larutan hara yang terdiri dari 3 taraf. Perbandingan air, larutan A, larutan B, dan pupuk cair (v/v) yaitu P0 (kontrol) = 1000:5:5:0, P1 =1000:5:5:5, dan P2 = 1000:5:5:15. Parameter yang diamati adalah tinggi tanaman, jumlah daun, jumlah cabang, luas daun, berat segar, berat kering, dilakukan juga uji kualitatif kandungan nitrat daun. Hasil penelitian menunjukkan bahwa perlakuan P0 memiliki pertumbuhan tercepat, sedangkan pertumbuhan paling lambat terlihat pada P2. Uji nitrat daun P2 menunjukkan hasil yang negatif. Perlakuan P0 juga memiliki berat segar dan berat kering tanaman yang paling tinggi dibanding dua perlakuan lainnya. Penambahan pupuk anorganik cair tidak dapat meningkatkan pertumbuhan pada kangkung dan bayam., Hydroponics is an alternative method in vegetable cultivation, this method does not require a large area. Hydroponics production can be increased with the fulfilment of proper nutrition. This research aimed to analyze the effect of adding liquid inorganic fertilizer to the AB mix nutrient solution on water spinach and spinach growth. This research used a Randomized Block Design. The treatments observed were the concentration of nutrient solution which consisted of 3 levels. The treatments were mixed of water, solution A, solution B, and liquid fertilizer (v/v), namely P0 (control) = 1000:5:5:0, P1 =1000:5:5:5, and P2 = 1000:5:5:15. The parameters observed were plant's height, number of leaves, number of branches, leaves area, leaves nitrate content, and plant fresh and dry weights. The results showed that the P0 treatment had the fastest growth, while the slowest growth was seen in P2. The leaf nitrate test of P2 plants showed negative results. The P0 treatment also had the highest fresh and dry weights per plant compared to the other two treatments. The addition of liquid inorganic fertilizer did not increase the growth of water spinach and spinach.
Keyword: AB mix, hydroponics, liquid inorganic fertilizer, spinach, water spinach

Judul: The Production and Application of Liquid Organic Fertilizer (LOF) as Nutrient Substitution of AB Mix on the Water Spinach (Ipomoea reptans) Growth in the Hydroponic Wick System
Abstrak: Nutrisi AB mix yang beredar di pasaran memiliki harga yang relatif tinggi, sehingga dibutuhkan alternatif lain yang lebih ekonomis. Salah satu alternatif yang dapat dilakukan adalah dengan menggunakan Pupuk Organik Cair (POC) buatan sendiri. Penelitian ini dilakukan untuk mengetahui kualitas POC berbahan dasar limbah kulit pisang dan cangkang telur ayam, mengetahui pengaruh POC terhadap pertumbuhan tanaman kangkung pada hidroponik wick system, dan mengetahui apakah POC dapat digunakan sebagai substitusi nutrisi AB mix. Tahapan penelitian meliputi tiga tahap, tahap pertama merupakan analisis unsur hara bahan baku. Tahap kedua, pembuatan POC dan analisis unsur hara. Hasil fermentasi pupuk disebut POC PT. Tahap ketiga, uji tanam pada tanaman kangkung pada hidroponik wick system. Percobaan disusun menggunakan Rancangan Acak Lengkap (RAL) dengan lima perlakuan pupuk yaitu P0 (kontrol), P1 (nutrisi AB mix), P2 (POC PT 150%), P3 (POC PT 100%), P4 (POC PT 50%) dengan tiga kali ulangan. Analisis data menggunakan sidik ragam (ANOVA) dan uji DMRT. Hasil analisis menunjukkan bahwa POC yang telah difermentasi selama tiga minggu memiliki kandungan unsur hara yang rendah dan belum memenuhi standar Kementerian Pertanian. Hasil uji tanam pada perlakuan POC PT di satu MST menghasilkan nilai pertumbuhan tanaman lebih rendah dibandingkan dengan perlakuan nutrisi AB mix sehingga perlu dilakukan penambahan pupuk Ca(NO3)2. Perlakuan POC PT memiliki nilai yang lebih tinggi dibandingkan dengan perlakuan kontrol pada seluruh parameter pertumbuhan tanaman kangkung. POC PT sebagai substitusi nutrisi AB mix belum mampu memberikan pertumbuhan optimal pada pertumbuhan kangkung di hidroponik wick system, The price of AB mix is relatively high, so it needed to find another alternative with a more economically price. One of alternative was Liquid Organic Fertilizer (LOF). This study was aimed to know the quality of LOF made from banana peel and chicken egg shells, the effect of LOF on the water spinach grown in the hydroponic wick system, and whether LOF can be used as a substitute for AB mix. The experiment consisted of three stages. First stage was nutrients analysis of raw materials. Second stage was the production of LOF and nutrients analysis. The results of fermented fertilizers called POC PT. Third stage was experiment on water spinach in a hydroponic wick system. The experiment used Completely Randomized Design (CRD) with five fertilizer treatments, namely P0 (control), P1 (AB mix nutrition), P2 (LOF PT 150%), P3 (LOF PT 100%), P4 (LOF PT 50%) in three replications. Data was analyzed using analysis of variance (ANOVA) and DMRT test. The experiment showed that LOF which was fermented for 3 weeks have a low nutrient content and below the standard of Ministry of Agriculture. The results showed that LOF PT in one week after planting have lower plant growth compare to the AB mix nutrient so it was necessary to add Ca(NO3)2 fertilizer. The LOF PT treatment have higher plant growth parameter than the control treatment. Thus, the treatment of LOF PT could not subtitue AB mix.
Keyword: pupuk organik cair, limbah cangkang telur, limbah kulit pisang, fermentation, chicken egg shells, banana peel waste

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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