Judul: Turnover Bahan Organik Tanah pada Berbagai Tipe Vegetasi di Ekosistem Mangrove Desa Blanakan, Kecamatan Blanakan Kabupaten Subang
Abstrak: Soils on mangrove ecosystem generally contain higher C-org than mineral soils on terrestrial ecosystem. The organic matter remained in soil as carbon deposit should be protected for its existence. This research aims to determine litter production, soil organic matter (SOM) content and how long SOM persists on mangrove ecosystem under various main vegetations. Materials used in this research include litters of various main vegetation on mangrove ecosystem i.e. Rhizophora, Avicennia, Sonneratia, and Bruguiera, and also disturbed soil samples from each mangrove vegetation. Those materials were analysed in laboratory, especially for measuring C-org content. The results showed that the average of litter production on mangrove ecosystem at Desa Blanakan, Kecamatan Blanakan, Kabupaten Subang is 10.02 ton/ha/year. The highest litter production was found for Sonneratia i.e. 18.38 ton/ha/year, followed by Bruguiera i.e. 10.14 ton/ha/year, Avicennia i.e. 6.96 ton/ha/year, and Rhizosphora i.e. 4.61 ton/ha/year. Soil C-org under Bruguiera vegetation in each soil depth was higher than soil Corg under Rhizophora, Avicennia, and Sonneratia vegetations. Soil C-org per hectare within 0-50 cm ranges between 59.38-67.25 ton in each main vegetation area. Average litter productions contribute 1.29-4.75 ton/ha organic carbon every year. Soil organic matter turnover under Sonneratia was faster than other main vegetations on mangrove ecosystem. Organic matter turnover on Sonneratia was 13 years, followed by Bruguiera, Avicennia, and Rhizospora i.e. 24, 27, and 48 years, respectively
Keyword: turnover, organic carbon, mangrove, litter production

Judul: Hubungan Sifat Tanah dan Tipe Vegetasi Mangrove di Desa Blanakan, Kabupaten Subang.
Abstrak: Mangrove ecosystem is a typical marine tropics and subtropics with a very important role for the balance of nature. However, currently the target of exploitation of mangrove forests due to the demands of development which focuses on economic interests. More than a half of the mangrove forest area in Indonesia in a bad damaged state, around the North Coast of Java, has long been eroded by the needs of its population to the land. Mangrove forests that relatively in good condition on the north coast of Java is in the village Blanakan, so the mangroves in the area need to be in the preserve. This study aims to determine the nature and characteristics of soil that affect the growth of mangrove land the village and to know the relationship of the soil properties with different types of mangrove vegetation that grows in the village Blanakan. There are 4 zones studied based on the type of vegetation growing in these locations. Zone 1 (BSR1) with vegetation Avicennia marina, zone 2 (BSR2) with Rhizophora mucronata vegetation, zone 3 (BSR3) with vegetation Jeruju, and zone 4 (BSR4) with vegetation Sonneratia acida. The sample of soil that have been researched are morphological and chemical properties. All of soil conditions are not significantly different by morphology. Those all zones are type Hydraquent soil. Chemical properties which have an influence on mangrove vegetation difference are the Electrical Conductivity (DHL/EC), water content at field condition, percentage saturation of the cations, the percentage of ESP, and SAR values, and value of soil. The DHL/EC, the percentage of ESP, and SAR values show the influence of sea water. Zone 1 had the soil more ripe than zone 2, 3, and 4. Cation saturation of each zone has its own characteristics. A base saturation zone was dominated by sodium saturation and followed by increasing the depth of soil. Zone 1 showed many salt-free and the salt free content increased from the upper to the lower layer. Base saturation in zone 2, between the top layer of soil is different from the middle layer and bottom layer. The top layer of soil in zone 2 was dominated by the saturation of magnesium, but in the middle layer and bottom layer was dominated by sodium saturation. Sodium saturation in zone 2 further decreased, this suggest that salt-free in this zone was diminishing compared to zone 1. In zone 3 and zone 4, there are no free salts and base saturation was dominated by magnesium, and also increased of addition calcium.
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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