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: Pertumbuhan Bibit Sengon (Paraserianthes falcataria (L) Nielsen) pada Media Bekas Tambang Pasir dengan Pemberian Subsoil dan Arang Batok Kelapa
Abstrak: Exploitation of natural resources in order to meet the increasingly commonplace as the needs of the population increase. Exploitation are likely to cause environmental damage. One such activity is the mining of sand. River sand mining will lead to a sustained decrease in the amount of sand in the river bed. As a result, the river will be damaged by excavation continues. In addition to damaging the ecosystem of the river, sand mining has also led to a decrease in water quality and air pollution. In order to reduce the impact of damage, utilization and processing of mining waste as a growing medium in a first step into alternative revegetation can be done. However, low nutrient content and CEC and texture of sand dominated an obstacle in the utilization of tailings sand as a growing medium. Application subsoil and the addition of coconut shell charcoal is expected to help improve these constraints. Sengon is a very fast growing plant and has a high potential and has been widely known to the public. These plants are best used in the post-mining land rehabilitation. The results showed that the addition of the interaction of subsoil and coconut shell charcoal gives the best growth of influence. Interaction addition of 75% subsoil and charcoal 40 g (a3b2) is the best treatment to improve seedling height by 64%. While the increase in diameter increment, the interaction of subsoil 75% and the addition of 60 g charcoal (a3b3) is the best treatment with the addition of a diameter of 87.50%. The best treatment for weight parameters in total bases (BKT) and total dry weight (BKT) indicated by the treatment (a3b3) with a 63.49% increase% and 36.10%. Giving a single charcoal best in show at the addition of 60 g charcoal (a0b3). Indicated by a high addition of 47.32%. While granting subsoil singly not give significant effect on seedling growth.
Keyword: sengon, subsoil, Charcoal, mining sand

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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