Judul: Effectiveness Bio-Fertilizers in the Pre Nursery of Oil Palm
Abstrak: The development of oil palm plantations in Indonesia currently has an impact on the demand for synthetic fertilizers because they contain higher nutrients. Intensive use of synthetic fertilizers needs attention because it can reduce soil quality and soil biodiversity. Therefore, a combination of synthetic fertilizers and bio-fertilizers is needed. The research method used was factorial randomized block design (RBD) with the first factor was fertilizer NPK which consisted of 4 levels of fertilizer doses 0%, 50%, 75%, and 100%. The second factor is biofertilizer which consists of four levels, without biofertilizer, 1ml PHC / L water, 2ml PHC / L water, and 30g mycorrhizae where grups were replicates. The combination treatment of NPK fertilizer at a dose of 50% with twice the recommended dosage of liquid biofertilizer gave the best results on the performance of oil palm in the pre-nursery. Mycorrhizal treatments singly or in combination with NPK fertilizer at doses of 50% and 75% significantly affected the percent of root colonization. The combination of liquid biofertilizer with NPK at a dose of 75% and 100% had a significant effect on the total soil N and plant N. Single treatment of mycorrhizae and its combination with NPK fertilizer at a dose of 75% showed the best results on available soil P.
Keyword: biofertilizer, mycorrhizae, oil palm, pre nursery

Judul: The role of organic fertilizer to increase the effectivity of NPK fertilizer for oil palm seedling (Elaeis guineensis Jacq.)
Abstrak: Oil palm has higher palm oil productivity than the others. So that, the precision plantation technology of oil palm cultivation must be done in order to preserve high productivity of oil palm. A seedling is the first step that affecting for oil palm’s age and productivity. Good growth will produce high quality and production of oil palm. The necessity of oil palm seedlings to intensify areal and replant would grow continuously, so it has needed to obtain precise fertilization. The objectives of this experiment were (1) to obtain the best organic-NPK fertilizer combination in increasing the effectiveness of the use of NPK fertilizer, (2) to study the role of organic fertilizer for the growth of oil palm seedling in main nursery, and (3) to investigate the efficiency of NPK fertilizer for best combination. The experiment was conducted from December 2011 to September 2012 at IPB Teaching Farm Dramaga Bogor. The layout was arranged in a factorial random block design with three replications. The first factor was volume ratio organic fertilizer to top soil i.e 0, 1:6, 2:6, and 3:6. The second was NPK Fertilizer rates i.e 0.0, 127.5, 255.0, and 382.5 g NPK.plant-1. Each of treatments have 5 plants, so that the numbers of sample were 240 plants. The result showed that combination of organic and NPK fertilizer significantly affected to plant height, leaf number, steam diameter, leaf area, and chlorophyll content. The interaction between organic and NPK fertilizer significantly affected to plant height at 8 Months After Transplanting (MAT)), leaf number (5-8 MAT), steam diameter (8 MAT), leaf area (3 MAT) and chlorophyll number (4 MAT). Organic fertilizer had increased the effectiveness of NPK fertilizer for oil palm seedlings, in this research the highest effective value was organic fertilizer 2:6 (organic fertilizer : top soil) and NPK 382.5 g plant-1 with the effective value was 179.38%. The only application of organic fertilizer 3:6 has showed oil palm seedling that no significant with NPK application from 127.5-382.5 g tanaman-1 without organic fertilizer. So that, organic fertilizer 3:6 could be substituted of NPK fertilizer. The best combination treatment was 2:6 and 382.5 NPK g plant-1 with effective value was 158.91%, 209.14% and 170.10% for plant height, leaf number and stem diameter, respectively. Organic fertilizer had increased the efficiency of NPK fertilizer with absorption rates of N, P and K was 56.16%, 11.06% and 29.90%.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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