Judul: Pemanfaatan Limbah Substrat Jamur Tiram dan Penambahan Sumber Nutrisi pada Budidaya Jamur Tiram Putih
Abstrak: Oyster mushroom or Pleurotus ostreatus (Jacq:Fr) Kummer is a type of wood-rot fungi commonly found in nature. White oyster mushroom has been widely marketed in the form of fresh or was processed like mushrooms chips. Substrates commonly used for the development of oyster mushroom cultivation is sawdust of Falcata. The more number of oyster mushroom cultivation gave the more waste of its substrate, while this waste still has nutrients that can be re-used for the cultivation of oyster mushroom. The objective of this study was to study the effect of the use of waste oyster mushroom substrate and liquid organic fertilizer to the growth and yield of oyster mushroom cultivation. Stages in this research consisted of substrate creation, seeding or inoculation, caring and observation of fungal development, and chemical composition analysis. The observations were the growth during the vegetative phase and reproductive phase, the character of the fruit body morphology, and the chemical composition analysis results of oyster mushroom fruiting bodies. The composition media of 75% spent mushroom substrate mixed with 25% of new mushroom substrate gave the best result on growth and mushroom yields. Concentration of 0.2% and 0.5% liquid organic fertilizer gave best yields. Besides the media and genetic factors, environmental factors such as temperature, humidity, and light affected the growth and yield of oyster mushroom.
Keyword: Pleurotus, oyster mushroom, mushroom substrate, mushroom cultivation, liquid organic fertilizer, Bogor Agricultural University (IPB)

Judul: Pengaruh Limbah Substrat Jamur Tiram dan Pupuk Organik Cair terhadap Budidaya Jamur Tiram Biru
Abstrak: Pleurotus spp. is one of wood-rot fungi that found in nature and has a good potential to be developed for cultivation. The decrease of raw material for re-used oyster mushrooms media provide an opportunity to recover residual spent mushroom substrate. More advanced technology, the use of liquid organic fertilizer is intended to supplement the mushrooms by needed nutrients. The purpose of this research was to analyze the effect of spent oyster mushrooom substrate and liquid organic fertilizer on the growth of blue oyster mushroom. The research consisted of two factors, the ratio of spent mushroom substrate and the concentration of liquid organic fertilizer with three replications for each factor. The result of this research indicated that factor spent mushroom subsrate and liquid organic fertilizer significantly affected the weight of wet blue oyster mushrooms. The ratio of 75% spent mushroom substrate combined with 25% new substrate of sengon with the concentration of the liquid organic fertilizer 0.2%, gave the highest wet weight of fruiting bodies (140 gram) and the highest biology efficiency (70%). While for the diameter of pileus, length of stalk, width of stalk, and total of stalk were not significantly affected. The use of spent mushroom subsrate with a liquid organic fertilizer could be used as a media for the cultivation of oyster mushroom.
Keyword: Bogor Agricultural University (IPB), spent oyster mushroom substrate., new substrate of sengon, liquid organic fertilizer, cultivation, blue oyster mushroom

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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