Judul: Reklamasi lahan pascatambang timah dan tingkat perkembangan wilayah di Kabupaten Bangka
Abstrak: Tin mining industry in Bangka Regency contributes positively to the national income, and increase in Gross Regional Domestic Product (GRDP), labour availability, and economic value. The tin mining also poses negative impacts on the environment. Post-mined reclamation is expected to increase regional economic level and stimulate economic growth so that after the closure of mining activities there is no inequality in the community socio-economic aspect. The aims of the research are: (1) to assess tin post-mined land reclamation techniques for plant growth, (2) to assess the types of reclamation plants suitable to grow and have an economic benefit to the community, (3) to determine priority of the reclamation plant types suitable to grow based on the stakeholders perceptions, (4) to plan an arrangement of plant types and land reclamation techniques in the tin post-mined area, and (5) to determine the level of the community income and regional development in villages with tin mining activities in Bangka Regency. The results show that the reclamation technique that can be implemented was by providing soil ameliorants (manure or compost, top soil and rock phosphate or dolomite) and fertilizers to the tailings, and then provide MAF inoculant or planting cover crops of the leguminoseae familiy and planted with native plants or plants which suitable to grow in the such a tin postmined land conditions. Implementation of the reclamation technique resulted in an increase in land suitability classes to be S3 (marginally suitable) for rubber (Hevea brasiliensis) and S2 (moderately suitable) for sengon (Paraserianthes falcataria) and acacia (Acacia auriculiformis). Based on the stakeholder perception, rubber is the priority plant, while plant which generate economic benefit is sengon. The community income of villages around the tin mining area increased in the period of 2003-2008. At the time of mining activities, hierarchy of some villages around the mine increased but then decreased after the closure of the tin mining activities.
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Judul: Kajian Awal Potensi Tumbuhan Indigenous dan Keragaman Funginya untuk Revegetasi Lahan Bekas Tambang Timah di Pulau Bangka
Abstrak: Activity of tin mining had negative impact on the ecosystem including decreasing in soil fertility. Effort had been done to revegetate the post tin mining land, however, the plant used was mainly Acacia mangium. This because the plant was ease to grow in marginal land, including post tin mining site. The potential indigenous plant is defined as indigenous plants that have potency to be used in revegetation program of the post tin mining land. The objective of this research was to examine the potency of indigenous plants and diversity of fungi that were associated with the potential plant for revegetation program of post tin mining land. Five experimental sites were selected, they were revegetated lands of 0 year (Jongkong 5E), 3 years (Jongkong 24), 16 years (Jongkong1), and 28 years (Nibung 2), and secondary forest as a control treatment. The parameters mesuared for determining the potency of indigenous plants were Important Value Index, production and decomposition rate of litter fall. The soil characteristics that were determined plant growth such as physical and chemical properties were also measured. Litter fall analysis was carried out based on predominant tree found in all sites. Fungal diversity was studied by isolation and identification of the fungi grown in roots, leaf litters, and rhizosfers. The vegetation analysis showed that the plants were grow in all research sites were Dyera costulata, Schima wallichii, and Acacia mangium. The production and decomposition rate of litter fallnin all sites were varied. The production of litter fall from Acacia mangium in Jongkong 1 was 3.79x10-4 ton/ha/year. The highest decomposition rate of litter fall was found Nibung 2 from Dyera costulata was 16.36/year with residience time 0.06 years. The fungal diversity isolated from dominant vegetation in tree stage category was high. The average of each plant harboured 26-30 fungi that were grown in roots, leaf litters, and rhizosfers of the plants. Trichoderma was the dominant fungi. Based on the data of vegetation analysis, production and decomposition rate of litter fall and fungal diversity, Dyera costulata and Schima wallichii were the potentional plants for revegetation program of post tin mining land.
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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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