Judul: Potential Utilization of Available Undergrowth Biomass on Potential Burning Areas
Abstrak: Tumbuhan bawah dan rumput kumpai merupakan biomassa yang keberadaannya dianggap menjadi salah satu faktor pemicu terjadinya kebakaran lahan. Hal ini terjadi karena karakteristik tumbuhan bawah yang rentan terhadap kekeringan, mudah terbakar, dan cepat dalam menyebarkan api. Situasi ini terjadi terutama pada kondisi iklim ekstrem seperti kemarau berkepanjangan dan akibat aktivitas manusia, baik yang disengaja maupun akibat kelalaian. Padahal, tumbuhan bawah memiliki peran dan manfaat yang penting salah satunya dalam siklus dan konservasi hara. Tujuan dari penelitian ini adalah mengetahui kandungan unsur hara tumbuhan bawah sebagai database dalam potensi pemanfaatannya. Sampel tumbuhan bawah diambil di 2 lokasi berbeda di area HTI, Kab. Banyuasin, melalui pemangkasan pada petakan berukuran 1x1 meter. Kandungan hara makro dan mikro tumbuhan dianalisis menggunakan metode pengabuan kering. Hasil analisis kandungan unsur hara makro tumbuhan bawah di area Green Belt diperoleh N-total sebesar 2,08%, P-total 0,12%, Ca 536,0 mg/100g, Mg 258,6 mg/100g, dan K 1458,3 mg/100g. Sementara itu, rumput kumpai sekitar Sungai Merang diperoleh N-total sebesar 2,59%, P-total 0,15%, Ca 2,9 mg/100g, Mg 10,2 mg/100g, dan K 1946,9 mg/100g. Kandungan hara mikro pada tumbuhan bawah area Green Belt diperoleh Fe sebesar 190,6 ppm, Cu 8,4 ppm, Zn 24,0 ppm, dan Mn 68,24 ppm. Pada rumput kumpai di sekitar Sungai Merang diperoleh Fe 785,1 ppm, Cu 14,0 ppm, Zn 24,6 ppm, dan Mn 21,2 ppm. Kandungan hara biomassa tumbuhan bawah berpotensi sebagai pupuk melalui proses dekomposisi alami dan sebagai sumber pakan ternak dengan kadar protein kasar sebesar 16%. Kata kunci : kandungan hara, pakan ternak, pupuk, rumput kumpai, tumbuhan bawah, The presence of undergrowth and kumpai grass is a biomass that is considered to be one of the factors that trigger land fires. This is due to the characteristics of the undergrowth, which is susceptible to drought, flammability and the rapid spread of fire. This situation occurs, especially in extreme climatic conditions such as prolonged drought and due to human activities, both intentional and negligent. On the other hand, undergrowth has roles and benefits, one of them is in nutrient cycling and conservation. The purpose of this study was to determine the nutrient content of undergrowth plants as a database for their potential utilization. Samples were taken in 2 different locations in the HTI area, Banyuasin Regency, through pruning on 1x1 meter plots. The macro and micronutrient contents of the plants were analyzed using the dry ashing method. The results of the macronutrient content analysis of the undergrowth plants in the Green Belt area obtained N-total 2,08%, P-total 0,12%, Ca 536,0 mg/100g, Mg 258,6 mg/100g, and K 1458,3 mg/100g. Meanwhile, kumpai grass around Merang River obtained N-total 2,59%, P-total 0,15%, Ca 2,9 mg/100g, Mg 10,2 mg/100g, and K 1946,9 mg/100g. The micronutrient content in the undergrowth of the Green Belt area obtained Fe 190,6 ppm, Cu 8,4 ppm, Zn 24,0 ppm, and Mn 68,24 ppm. In kumpai grass around the Merang River, Fe 785,1 ppm, Cu 14,0 ppm, Zn 24,6 ppm, and Mn 21,2 ppm. The nutrient content of undergrowth biomass has the potential to be use as fertilizer through natural decomposition and as a source of animal feed with a
Keyword: kandungan hara, pakan ternak, pupuk, rumput kumpai, tumbuhan bawah, animal feed, fertilizer, kumpai grass, nutrient content, undergrowth

Judul: Pendugaan Potensi Biomassa, Karbon, dan Serapan CO2 pada Tumbuhan Bawah di Hutan Pendidikan Gunung Walat (HPGW), Sukabumi
Abstrak: Tumbuhan bawah adalah suatu jenis vegetasi dasar yang terdapat di bawah tegakan hutan meliputi rerumputan, herba, perdu, dan paku-pakuan. HPGW merupakan hutan tanaman yang telah berubah menjadi hutan alam, sehingga potensi tumbuhan bawah di lokasi tersebut melimpah. Penelitian bertujuan untuk mengetahui potensi biomassa dan cadangan karbon pada tumbuhan bawah serta mengetahui potensinya dalam menyerap karbon dioksida (CO2). Teknik pengambilan data menggunakan metode simple random sampling, dimana plot sampel ditempatkan secara acak tanpa memperhatikan strata yang ada dalam populasi. Plot contoh yang digunakan adalah persegi dengan ukuran (2 × 2) m, total plot contoh yang digunakan dalam penelitian ini adalah 83 plot. Pengambilan data dilakukan di lapangan dan di laboratorium. Pengambilan data lapangan menggunakan metode destructive sampling (memanen seluruh bagian tumbuhan bawah, kecuali akar). Pengambilan data di laboratorium menggunakan oven dengan suhu 105°C dalam waktu 24 jam. Hasil penelitian menunjukkan bahwa rata-rata potensi biomassa, karbon, dan serapan karbon dioksida pada tumbuhan bawah berturut-turut yaitu sebesar 1,16 ton ha-1, 0,55 ton ha-1, dan 2,01 ton ha-1., The undergrowth is a type of base vegetation found under forest stands including grasses, herbs, shrubs, and ferns. HPGW is a plantation forest that has changed into a natural forest, so the potential for undergrowth in that location is very abundant. This study aims to determine the potential for biomass and carbon stock stored in understory plants and determine their potential to absorb carbon dioxide (CO2). The data collection technique used a simple random sampling method, where the sample plots were placed randomly without regard to the existing strata in the population. The sample plot used is a square with a size of (2 × 2) m, the total sample plot used in this study is 83 samples. Data collection is carried out on the ground and in the laboratory. Data collection in the field used the destructive sampling method (harvesting all parts of the understory, except for the roots). Data were collected in the laboratory using an oven with a temperature of 105°C for 24 hours. The result showed that the average potential for biomass, carbon stock, and carbon dioxide absorption in the undergrowth was 1,16 ton ha-1, 055 ton ha-1, and 2,01 ton ha 1, respectively.
Keyword: biomass, carbon dioxide, carbon stock, HPGW, undergrowth

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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