Judul: Decomposition Rate and Site Characteristics in the Agroforestry System at Mount Kendeng Resort, Mount Halimun Salak National Park.
Abstrak: Leaf litter has a positive influence on the physical and chemical properties of soil through the provision of organic matter on the soil surface. This study aimed to measure the decomposition rate of leaf litter, and analyze the relationship between site characteristics and environmental conditions on the decomposition rate in agroforestry systems areas. Vegetation analysis was carried out on 50 m x 50 m sample plots totalling 14 plots. In addition, decomposition rate analysis, site characteristics, climate, and correlation tests were carried out. The dominant tree species in agroforestry systems areas was Agathis dammara. The highest and lowest decomposition rates in agroforestry systems areas at Gunung Kendeng Resort were 0.57 g/day and 0.33 g/day, respectively. The correlation between decomposition rate and edaphic factors that had a positive correlation were pH, soil organic matter, organic carbon, and porosity, while soil temperature, soil respiration, and bulk density had a negative correlation. The correlation between decomposition rate and climatic factors that had a positive correlation was moisture, while air temperature and light intensity had a negative correlation., Serasah memiliki pengaruh yang positif terhadap sifat fisik dan kimia tanah melalui penyediaan bahan organik di permukaan tanah. Penelitian ini bertujuan untuk mengukur laju dekomposisi serasah daun, dan menganalisis hubungan karakteristik tapak dan kondisi lingkungan terhadap laju dekomposisi pada areal sistem agroforestri. Analisis vegetasi dilakukan pada plot contoh 50 m×50 m sebanyak 14 plot. Selain itu, dilakukan analisis laju dekomposisi, karakteristik tapak, dan klimatis, serta uji korelasi. Jenis pohon yang mendominasi pada areal sistem agroforestri adalah Agathis dammara. Laju dekomposisi tertinggi dan terendah pada areal dengan sistem agroforestri di Resort Gunung Kendeng secara berturut-turut sebesar 0,57 g/hari dan 0,33 g/hari. Hubungan korelasi laju dekomposisi dengan faktor edafis yang memiliki korelasi positif adalah pH, bahan organik tanah, C-Organik, dan porositas, sedangkan suhu tanah, respirasi tanah, dan bulk density memiliki korelasi negatif. Hubungan korelasi laju dekomposisi dengan faktor klimatis yang memiliki korelasi positif adalah kelembapan, sedangkan suhu udara dan intensitas cahaya memiliki korelasi negatif.
Keyword: agroforestri, dekomposisi, karakteristik edafis, karakteristik klimatis, serasah

Judul: Decomposition rate of leaf litter at Density Class I and II in the Rehabilitation Zone of Mount Halimun Salak National Park
Abstrak: Salah satu bahan organik alami yang dihasilkan dari tanaman yaitu serasah. Serasah menjadi tempat proses biologi tanah yaitu dekomposisi. Dekomposisi memegang peranan yang penting dalam siklus ekologi di hutan yang merupakan asupan unsur hara ke dalam tanah. Penelitian ini bertujuan untuk memberikan informasi terkait pengaruh vegetasi terhadap laju dekomposisi dan karakteristik tanah serta memberikan informasi terkait pengaruh faktor edafis dan klimatis terhadap laju dekomposisi di zona rehabilitasi Taman Nasional Gunung Halimun Salak. Dekomposisi serasah dilakukan menggunakan litterbag yang diletakkan pada plot berukuran 50 m x 50 m. Hasil penelitian selama 90 hari menunjukkan bahwa laju rata-rata dekomposisi serasah pada hari ke-30 sebesar 0,37 g/hari (Kelas I) dan 0,41 g/hari (Kelas II) dan terus mengalami peningkatan hingga hari ke-90 sebesar 0,41 g/hari (Kelas I) dan 0,47 g/hari (Kelas II). Peningkatan laju dekomposisi memiliki korelasi positif terhadap unsur klimatis (suhu udara, kelembapan, dan intensitas cahaya) dan unsur edafis yaitu sifat fisika tanah (porositas dan suhu tanah), sifat kimia tanah (pH tanah, bahan organik tanah, C-organik, dan N-total), dan sifat biologi (respirasi tanah). Laju dekomposisi berkorelasi negatif dengan bulkdensity dan C/N rasio., One of the natural organic materials produced from plants is litter. Litter becomes the site of the biological process of soil that is decomposition. Decomposition plays an important role in the ecological cycle in forests which is the intake of nutrients into the soil. This study aims to provide information related of vegetation on the rate of decomposition and soil characteristics and determine the influence of edafic and climatic factors on the rate of decomposition in the rehabilitation zone of Mount Halimun Salak National Park. Litter decomposition is carried out using litterbags placed on plots measuring 50 m x 50 m. The results of the 90-day study showed that the average rate of litter decomposition on the 30th day was 0,37 g/day (Class I) and 0,41 g/day (Class II) and continued to increase until the 90th day of 0,41 g/day (Class I) and 0,47 g/day (Class II). The increase in the rate of decomposition has a positive correlation with climatic elements (air temperature, humidity, and light intensity) and edafic elements, namely soil physical properties (porosity and soil temperature), soil chemical properties (soil pH, soil organic matter, C-organic, and N-total), and biological properties (soil respiration). Meanwhile, the rate of decomposition is negatively correlated with bulkdensity and C/N ratio.
Keyword: dekomposisi, edafis, klimatis, serasah, TNGHS

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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