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: Leaf Litter Decomposition and Soil Characteristics in The Mountain Rainforest Ecosystem of Gunung Halimun Salak National Park (TNGHS)
Abstrak: Hutan hujan pegunungan merupakan salah satu tipe ekosistem hutan hujan tropis dengan ketinggian 1.000 – 2.400 mdpl. Hutan hujan pegunungan di TNGHS terdapat di zona inti yang memiliki kondisi dan fungsi yang masih asli (alami). Serasah merupakan bahan baku proses dekomposisi yang menentukan siklus unsur hara dan kesuburan tapak. Penelitian ini bertujuan untuk menganalisis laju dekomposisi serasah daun pada ekosistem hutan hujan pegunungan dan menganalisis hubungan antara laju dekomposisi serasah daun dengan faktor-faktor lingkungan (kondisi vegetasi, edafis, dan klimatis). Laju dekomposisi serasah daun ekosistem hutan hujan pegunungan pada kelas kerapatan sedang meningkat dari hari ke-30 hingga ke-90. Pada kelas kerapatan tinggi laju dekomposisi serasah daun mengalami peningkatan yang tidak terlalu signifikan dari hari ke-30 hingga hari ke-90. Laju dekomposisi serasah daun memiliki korelasi positif dengan suhu udara, kelembapan udara, intensitas cahaya, bahan organik tanah, C-organik tanah, pH tanah, N-total, dan bulk density, serta memiliki korelasi negatif dengan suhu tanah, respirasi tanah, C/N rasio dan porositas tanah., Mountain rainforest is one of the types of tropical rainforest ecosystems with elevations ranging from 1.000 - 2.400 m asl. Mountain rainforests in TNGHS are located in the core zone, which has original (natural) conditions and functions. Leaf litter serves as the raw material for the decomposition that determines the nutrient cycle and soil fertility. This study aims to analyze the rate of leaf litter decomposition in mountain rainforest ecosystems and to examine the relationship between the rate of leaf litter decomposition in mountain rainforest ecosystems and environmental factors (vegetation conditions, edaphic factors, and climatic factors). The rate of leaf litter decomposition in the lower mountain forest ecosystem increased from day 30 to day 90 in the medium-density class. In the high-density class, the rate of leaf litter decomposition experienced a less significant increase from day 30 to day 90. The rate of leaf litter decomposition is positively correlated with air temperature, air humidity, light intensity, soil organic matter, soil organic carbon, soil pH, N-total, and bulk density, while it is negatively correlated with soil temperature, soil respiration, C/N ratio, and soil porosity.
Keyword: Dekomposisi, Hutan Hujan Pegunungan, Hutan Tropis, Unsur Edafis, Unsur Klimatis

Judul: Query Expansion based on Bilingual Dictionary Using Conditional Probability
Abstrak: Query expansion is a technique that can be used to bridge vocabulary gaps between queries and documents in the collection. With query expansion, user will be helped to formulate queries well so that user will optimize the search result. In this study, the expansion term was resulted from the translation of bilingual dictionary. Subsequently, several terms of expansion were elected based on the closeness of its relationship with the original query. This research showed that conditional probability can be used to select expansion term in bilingual translation method query expansion. The result of 1000 documents was more than 97% relevan document can be retrieved by this system. The more expansion term used, the larger number relevan document was retrieved.
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