Judul: Weeds and Weed Seed Bank as Components of Agrobiodiversity in Palm Oil Plantations
Abstrak: Gulma dan weed seed bank merupakan komponen penting dari keanekaragaman hayati dalam agroekosistem perkebunan kelapa sawit. Tujuan dari penelitian ini adalah mempelajari komposisi, distribusi, dan dinamika gulma serta seed bank gulma dalam tanah di perkebunan kelapa sawit. Penelitian dilakukan pada bulan November 2023 hingga Februari 2024 di Perkebunan Kelapa Sawit Bangun Bandar PT. Socfindo, Medan, Sumatera Utara. Penelitian dilakukan dengan menggunakan metode observasi dengan meninjau langsung keberadaan gulma di lapangan. Penentuan lokasi penelitian dilakukan secara purposive berdasarkan berbagai tahun tanam yang berbeda. Teknik pengambilan sampel dilakukan dengan sistem simpel random sampling dengan metode kuadrat berdasarkan kriteria kedalaman tanah dan tahun tanam kelapa sawit. Faktor pertama adalah tahun tanam kelapa sawit yaitu kelapa sawit dengan tahun tanam 2022, tahun tanam 2019, tahun tanam 2012, dan tahun tanam 2004 sedangkan faktor kedua adalah kedalaman tanah yang terdiri dari kedalaman tanah 0-10 cm, kedalaman tanah 10-20 cm, dan kedalaman tanah 20-30 cm. Faktor lingkungan seperti suhu, kelembapan udara, dan intensitas cahaya di bawah tegakan kelapa sawit berpengaruh pada jenis gulma yang dominan tumbuh. Komposisi gulma juga bervariasi berdasarkan tahun tanam, dengan rerumputan mendominasi pada tanaman muda dan daun lebar pada tanaman yang lebih tua. Analisis koefisien komunitas menunjukkan perubahan dalam homogenitas komunitas gulma seiring dengan pertambahan tahun tanam, mungkin terkait dengan pengaruh lingkungan dan praktik pertanian. Potensi soil seed bank gulma tertinggi terdapat pada kedalaman tanah 0-10 cm, dengan spesies seperti Cynodon dactylon dan Selaginella willdenowii mendominasi. Keanekaragaman gulma dalam soil seed bank bervariasi berdasarkan kedalaman tanah dan tahun tanam, menunjukkan pola dominasi yang bervariasi. Absennya beberapa spesies gulma di soil seed bank mengindikasikan potensi kehilangan biodiversitas terkait pentingnya perlindungan habitat alami dan pengelolaan gulma yang berkelanjutan untuk mempertahankan biodiversitas dalam ekosistem kelapa sawit., Weed and weed seed banks are crucial components in the agroecosystem biodiversity of oil palm plantations. This research was to study the composition, distribution, and dynamics of weeds, as well as the potency of the soil weed seed bank in oil palm plantations. The research was conducted between November 2023 and February 2024 at Bangun Bandar Oil Palm Plantation PT. Socfindo in Medan, using the observation method by directly reviewing the presence of weeds in the field. Determination of the research location was carried out purposively based on a variety of different planting years. The sampling technique was carried out with a simple random sampling system with the quadrat method based on the criteria of soil depth and oil palm planting year. The first factor is the year of oil palm planting (namely oil palm with planting year 2022, 2019, 2012, and 2004) while the second factor is three soil depths (0-10 cm, 10-20 cm, and 20-30 cm). Temperature, humidity, and light intensity around the oil palm canopy significantly impact the dominance of weed species. The study found that the composition of weeds varies depending on the age of the plants, with grasses being more prevalent in younger and broad-leaved weeds in older plants. The examination of weed community homogeneity using the community coefficient showed changes with increasing crop years, potentially due to environmental impacts and agricultural practices. The greatest potential
Keyword: Agroecosystem management, Biodiversity dynamics, Seed ecology, Vegetation diversity

Judul: Keragaman Tumbuhan Invasif di PT Perkebunan  Nusantara II Deli Serdang, Sumatra Utara
Abstrak: Salah satu penghambat produktivitas perkebunan sawit adalah gulma. Beberapa gulma termasuk dalam kategori tumbuhan invasif. Penyebaran serta pertumbuhan dari tumbuhan invasif yang tidak terkendali dapat menyebabkan kerugian serta ancaman secara ekonomi maupun ekologi. Penelitian ini bertujuan menganalisis keragaman tumbuhan invasif di kawasan kebun kelapa sawit PT Perkebunan Nusantara II. Sampel tumbuhan diambil dengan membuat petak contoh pada 3 blok yang berbeda dan ditempatkan secara purposive sampling. Selanjutnya, dilakukan identifikasi spesies dan analisis data yang mencakup Indeks Nilai Penting (INP), indeks keanekaragaman, indeks kesamaan dan indeks kemerataan. Spesies tumbuhan invasif yang ditemukan sebanyak 20 dari 61 spesies gulma yang berasal dari 13 famili. Spesies invasif yang ditemukan memiliki habitus herba, semak dan perdu. Spesies invasif didominasi oleh tumbuhan dari famili Poaceae dan Asteraceae. Jenis Asystasia gangetica, Mitracarpus hirtus, Peperomia pellucida dan Phyllanthus urinaria ditemukan dalam tiga blok. Namun, berdasarkan nilai INP hanya tiga spesies yang dapat tergolong memiliki pengaruh pada komunitasnya yaitu Phyllanthus urinaria, Setaria plicata dan Peperomia pellucida., Several species of weeds which are categorized as invasive plants are one of the causes of inhibiting plantation productivity. The uncontrolled spread andgrowth of invasive plants can cause economic and ecological losses. This study aimed to analyze the diversity of invasive species in the palm oil plantation area of PT Perkebunan Nusantara II. Plant samples were taken by making sample plots in 3 different blocks and placed by purposive sampling. Furthermore, species identification and data analysis were carried out including the Important Value Index (IVI), diversity index, similarity index and evenness index. There are 20 invasive species from 61 weed species belonging to 13 families. The invasive species have a habitus of herbs, bushes and shrubs. Invasive species are dominated by species from the families Poaceae and Asteraceae. Asystasia gangetica, Mitracarpus hirtus, Peperomia pellucida and Phyllanthus urinaria species were found in all three blocks. However, based on the IVI value, only three species can be categoried affecting the community, namely Phyllanthus urinaria, Setaria plicata and Peperomia pellucida.
Keyword: diversity, IVI, invasive species, purposive sampling, weeds

Judul: Synthesis of Molybdenum Trioxide (MoO3) by Electrochemical Method for Electrochromics Application
Abstrak: Molybdenum trioxide (MoO3) thin films have been deposited on glass substrates by electrochemical method using ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O244H2O). The films were deposited onto glass substrates as the control temperature at 25○C and annealing treatment at 350○C for 30 mins. The MoO3 thin films were investigated by UV-Vis, X-ray diffraction techniques (XRD), Scanning Electron Microscopy (SEM). The JCPDS card show that orthorhombic MoO3 (α- phase) has been formed. Molybdenum trioxide MoO3 formation was also confirmed by JCPDS card no. 35-0609. The SEM photographs revealed that the spherical and rod-like morphology and their grains size increased with increasing of heating temperatures. The measurement results show that the MoO3 thin film prepared at 350°C transmited about 80% of the visible spectrum. The effect of different heat treatments on surface morphology, thickness and optical properties of the films are discussed in this thesis.
Keyword: Institut Pertanian Bogor, Bogor Agricultural University, IPB, Electrophoretics, electrodeposide, electrochromics, electrochromic materials, electrochromic mechanism