Judul: Efektivitas Pupuk Organik terhadap Pertumbuhan, Produksi, dan Kadar Hara NPK Daun Jagung Manis di Latosol Darmaga
Abstrak: Sweet corn is seed plant which is commonly planted in Indonesia because of it's sweet taste and contain high carbohydrate. One of the problems in cultivation of sweet corn is low soil fertility, due to the lack of soil nutrient availability and organic matter. To solve that problem can be done by applying organic and anorganic fertilizers. Organic fertilizer is able to increase chemical fertilizer efficiency through improving of physical, chemical and biological of soil. So it is expected to increase the production of plant significantly. The objective of this research is to study the effectiveness of organic fertilizers that was combined with inorganic fertilizer on the growth, production, and N, P, K content of sweet corn leaf in Latosol Darmaga. The field experiment was conducted at the University Farm IPB and plant analisis in the laboratory of soil chemistry and fertility, Department of soil science and Land Resources Faculty of Agriculture IPB. The materials used were organic fertilizers, inorganic fertilizers, seeds of sweet corn (Seleksi Darmaga III), furadan, and agricultural lime. The design of the experiment was a randomized complete block design (RCBD) with a single treatment consisted of 7 treatments which was repeated 3 times each, so there were 21 experimental units. Those seven treatments were: (1) control, (2) Standard (S), (3) 0.5 S + 1.5 PO, (4) 0.5 S + 1 PO, (5) 0.75 S + 1 PO, (6) 1 S + 1 PO and (7) 0.75 S + 1.5 PO. The parameters measured were plant height, production (corn cobs weight including the cornhusk and stover weight), and N-, P-, K-content of corn leaf. The results of this research showed that additional of organic fertilizer with inorganic fertilizer was effective in improving the growth, production, and N, P, K content of sweet corn leaf. The production for treatment 1 S + 1 PO was 14.31 t/ha greater (2.37 t/ha) than standard treatment, and 11.81 t/ha greater than control treatment (no fertilizer application).
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Judul: Pengaruh Pupuk Organik dan NPK terhadap Serapan Hara dan Hasil Jagung Manis di Latosol Dramaga.
Abstrak: Sweet corn cultivation carried out by farmers around Bogor commonly only use inorganic fertilizers without incorporating the corn stalks into the soil and used as animal feed. Cultivation as above continously can lead to decreased of soil organic matter. This trial was conducted to test the effectiveness of organic manure and NPK fertilizer on the growth and yield of sweet corn. This trial was conducted in IPB experimental station at Cikabayan from May 2014 until November 2014. Factorial randomized block design was used in this trial with two factors. The first factor was the organic manure with 3 levels of dosages, namely: O0 = 0 t/ha, O1 = 2.5 t/ha (6:25 kg/plot) and O2 = 5 t/ha (12.5 kg/plot). The second factor was the NPK fertilizer with 4 levels namely: P0 = 0%, P1 = 50%, P2 = 75% and P3 = 100% standard dosage of NPK. Standard dosage of NPK fertilizer consisting of urea 250 kg/ha, SP-36 150 kg/ha and KCl 200 kg/ha. Variables measured were plant height, weight of cob and dry biomass, nutrient uptake and Relative Agronomic Effectiveness (RAE). The results showed that treatment of NPK fertilizer increased crop height while main effect of organic manure did not significantly incrace. Treatment with a combination of organic manure and NPK fertilizer increased the weight of cob and dry biomass. NPK fertilizers influenced the uptake of N, K and dry biomass, but not significanly on the uptake of P. Acording to relative agronomic effectiveness showed that the application of organic manure could reduce the NPK fertilizer.
Keyword: Nutrient uptake, yield, organic manure

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model