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: Kajian hasil-hasil penelitian tentang tingkat pertumbuhan berbagai jenis pohon pada lahan pasca tambang
Abstrak: Mining would give direct negative impact on environmental condition, there are opened soil surface that will increase surface run-off; change on forest ecosystem and forest ecology stability. Objective on post mining area rehabilitation is to construct post mining area fit in the land purpose. Collection results of researches in growth of many trees species is important to know the development of technique and detect the success rate with its factors. The objective of this research to evaluate result on researches collected. This research was carried out by collect and analyze the result of growth on many tree species in post mining area on Laboratorium Bioteknologi Hutan dan Lingkungan ; dan Pusat Penelitian Sumberdaya Hayati dan Bioteknologi (PPSHB) library, University library and Department of Forest Resources Conservation and Ecotourism library at Bogor Agricultural University. Many research resulted there were several tree species which used in rehabilitation post mining area were akasia, lamtoro, gamal, sengon, jarak pagar, pulai, gaharu, nyatoh, kapur naga, mindi, melochia, cemara gunung, nyamplung, ubak, rengkat, leban, and waru . Over tailing in post tin mining area akasia, lamtoro, gamal and sengon well grown with Mycofer and compost treatment beside that jarak pagar seedlings well grown in mixed ameliorant and anorganic fertilizer tratment. Over batu bara tailing, sludge acquition increasing growth of mangium and acacia. Topsoil acquition increasing seedlings growth of pulai species. FMA inoculation and soil amandement treatments increasing grown of agarwood species. Soil amandement treatment given positive effect on seedlings of nyatoh and kapur naga species. Over post gold mining area, combination of active compost and FMA helped mindi species to grown up. Over post nickel mining area, melochia species well grown in fertilizer treatments, beside that grass controlling system helped cemara gunung grown well. Over post tin mining area nyamplung, ubak, rengkat, laban and waru grown up with water splash treatment.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular