Judul: Peranan arang batang kelapa sawit dalam peningkatan produksi tanaman jagung (Zea mays, L.)
Abstrak: The main problem of continuously cultivated land is decreasing land productivity. Improvement of land productivity can be done by application of suitable soil ameliorant. Charcoal is one of soil ameliorants that can be used for improving soil properties such as to stimulate plant growth by providing and maintaining nutrients in the soil due to improving soil physical and biological properties. Abundant availability of oil palm trunks when oil palm replanting is an opportunity to utilize oil palm trunks as charcoal raw material. This research aimed to study the effect of charcoal from oil palm trunks on corn growth and production as well as to study tendency of the movement and development of roots grown on media with and without of charcoal from oil palm trunks. Soil material was taken from Latosol at a depth of 0-20 cm. The soil material was treated by charcoal from oil palm trunks as much as 0%, 4%, 8%, 12%, 16% and 20% (w/w) of the soil. The soil also was addded by basic N, P, and K fertilizers and then corn was planted. The results showed that soil treated by 4% of charcoal from oil palm trunks increased significantly corn growth and production. Application of higher charcoal rates did not increase the growth and production of corn, and moreover tended to decrease at 20% charcoal treatment. Biomass production of corn increased significantly compared to untreated charcoal. The porous structure of charcoal improve the structure of soils which allows roots capable to utilize more available nutrients as indicated by the evidence of more roots in the soil containing charcoal and increasing corn production.
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Judul: Pemanfaatan limbah penebangan menjadi arang untuk media tanam: studi kasus di PT. Austral Byna, Provinsi Kalimantan Tengah
Abstrak: Forest harvesting is extraction of forest products, timber and non-timber to be used. This activity relates with logging which generate waste of the cutting area with large enough in quantity. The big potential of timber waste which is big enough could be used rather than left in the forest. One of timber waste utilization is to make charcoal as the plantation medium. This is an effort to help overcome problems of marginal land in Kalimantan, which is dominated by red-yellow podzolic soil. Timber waste is used to produces charcoal through the combustion method pirolysis. Then charcoal and soil were mixed for geting ideal composition to be used as plantation medium. The composition of soil and charcoal mixture are given into polybag plantation medium size 10x15 cm with charcoal addition that is equal to 0%, 10%, 20% and 30%. Sengon were chosen as indicator of plantation growth because associated as fast growing species that could in different soil types, with simple silvicultural techniques. Charcoal addition significantly increased the growth on height, diameter, seedling dry weight and sturdiness of sengon seedlings. From the results of Completely Randomized Design (CRD) found that 10% charcoal addition into the plantation medium increased height by 37.15% compared to control, 30% the addition of charcoal increased 81,66% diameter compared to control. Total value of dry seedling weight in the end of the observation increased by 204.76% compared with control on the 10% charcoal addition. Value sengon seedling plantation medium 30% addition charcoal is 4,90 and the best in robustness compared to other seedlings. Charcoal addition of 30% were the suitable mixture of media for planting at nursery. Charcoal addition into the plantation medium increased sengon seedling growth, because charcoal contains nutrient elements wich could enhance the seedling growth. Moreover, the charcoal improve the texture of the polybag plantation medium in order to store the nutrients that plants need for growing well.
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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