Judul: Laju Dekomposisi Serasah Daun Shorea guiso di Hutan Penelitian Dramaga, Bogor, Jawa Barat
Abstrak: Dekomposisi serasah merupakan proses penguraian serasah yang menjadi kompenen penting dari proses siklus nutrisi karena dapat memberikan kontribusi besar terhadap kesuburan tanah. Tujuan penelitian ini adalah untuk mengukur laju dekomposisi serasah daun Shorea guiso serta kandungan bahan organik tanah dalam proses dekomposisi serasah daun Shorea guiso di Kawasan Hutan Penelitian Dramaga, Bogor, Jawa Barat. Dekomposisi serasah daun Shorea guiso dilakukan menggunakan litter-bag berukuran 30 cm x 40 cm. Setiap litter-bag berisi 100 g berat kering serasah Shorea guiso. Kantong serasah kemudian diikatkan pada patok bambu dan diletakkan di bawah tegakan Shorea guiso. Hasil penelitian selama 12 minggu menunjukkan bahwa laju rata-rata dekomposisi serasah daun tanaman Shorea guiso pada minggu ke-1 pengamatan sebesar 0,003 dan terus mengalami peningkatan hingga minggu ke-12 sebesar 0,2. Rata-rata laju dekomposisi serasah daun Shorea guiso mingguan sebesar 0,075 yang tumbuh pada tanah dengan kandungan BOT berkategori sedang (3,87%)., Litter decomposition is a process of decomposing litter which is an important component of the nutrient cycle process because it can make a major contribution to soil fertility. The purpose of this study was to measure the decomposition rate of Shorea guiso leaf litter and soil organic matter content in the decomposition process of Shorea guiso leaf litter in the Dramaga Research Forest, Bogor, West Java. Decomposition of Shorea guiso leaf litter is carried out using a liiter bag measuring 30 cm x 40 cm. Each litter-bag contained 100 g of dry weight of Shorea guiso litter. The litter bag was then tied to a bamboo stake and placed under the Shorea guiso stand. The results of this study for 12 weeks showed that the average of leaf litter decomposition rate of Shorea guiso at the 1 week of observation was 0,003 and continued to increase until the 12 week of 0,2. The average weekly rate of decomposition of Shorea guiso leaf litter was 0,075 which grew on soils with moderate BOT content (3,87%).
Keyword: Dramaga research forest, litter decomposition rate, Shorea guiso

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: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
Keyword: