Judul: Pertumbuhan Bibit Krey Payung (Filicium decipiens) pada Media Bekas Tambang Pasir dengan Penambahan Arang dan Pupuk NPK
Abstrak: Mining activity is one of exploitation natural resources exploitation which is consist of land clearing activities, extraction, dredging or landfill. One type of mining that usually do by the communities is sand mining. Problems arising from mining, among others, the land vulnerable to landslides, sedimentation of sand in the river, the potential for flooding in the lower areas, the loss of soil organic matter, loss of soil layer, soil structure changes, air pollution in the form of dust, and damage to rural roads. Revegetation should become a absolute activities on ex mined land, but revegetation efforts often face a very severe constraint. In the land of the former sand mining has dominated the sand texture with low KTK and low nutrient content. Charcoal and NPK fertilizer application expected to overcome it. Krey payung has good prospects for growing trees classified in different types of soil, and produce a lot of litter for soil improvement, and has a canopy and attractive leafy. The results showed that the greatest growth is combined with charcoal without NPK fertilizer and it gave krey payung seedling growth is best shown by the IMB (seed quality index) value of 29 points. Giving largest single charcoal which is 10% to the planting medium sand mined lands provide an krey payung seedling growth is best shown by IMB value of 28 points. Treatment given media without NPK fertilizer best response krey payung seedling growth indicated by IMB value of 30 points. The addition of NPK on soil media former sand mining respond less well on seedling growth krey payung.
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Judul: The Effect of MycoSilvi and Soil Ameliorant on The Growth of seedling Kayu Kuku (Pericopsis mooniana) on Silica Sand Post-Mining Land
Abstrak: Kegiatan pertambangan dapat menurunkan kesuburan tanah yang dicirikan oleh kandungan bahan organik yang rendah dan pH tanah yang masam, sehingga dapat menghambat kegiatan revegetasi. Kayu kuku merupakan salah satu jenis tanaman yang banyak digunakan untuk merevegetasi lahan pascatambang. Tujuan penelitian ini adalah menganalisa respon pertumbuhan semai kayu kuku (Pericopsis mooniana) dengan perlakuan MycoSilvi dan amelioran tanah pada media pascatambang pasir silika. Rancangan percobaan yang digunakan pada penelitian ini yaitu Rancangan Acak Lengkap (RAL) dengan tiga faktor perlakuan (MycoSilvi, arang tempurung kelapa dan pupuk kandang kambing). Hasil penelitian menunjukkan kombinasi 5 g MycoSilvi, 45 g arang tempurung kelapa dan 45 g pupuk kandang kambing merupakan kombinasi terbaik yang menghasilkan total laju pertumbuhan tinggi dan kandungan klorofil paling besar dibandingkan perlakuan lainnya., Mining activities can reduce soil fertility which is characterized by low organic matter content and acidic soil pH, which can inhibit revegetation activities. Kayu Kuku is one type of plant that is widely used for revegetating post-mining land. The purpose of this study was to analyze the growth response of kayu kuku (Pericopsis mooniana) seedlings with MycoSilvi treatment and soil ameliorant on silica sand post-mining soil. The experimental design used in this study was a Completely Randomized Design (CRD) with three treatment factors (MycoSilvi, coconut shell charcoal, and goat manure). The results showed a combination of 5 g MycoSilvi, 45 g coconut shell charcoal, and 45 g goat manure was the best combination that produced a high total growth rate and the greatest chlorophyll content compared to other treatments.
Keyword: Coconut shell charcoal, Goat manure, MycoSilvi, Pericopsis mooniana, post mine

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology