Judul: Vegetation Analysis and Weed Seed Bank in Various Cropping Patterns of Porang (Amorphophallus muelleri Blume)
Abstrak: Porang merupakan tanaman tahunan yang dapat tumbuh di berbagai pola tanam dan memiliki beberapa fase siklus tumbuh. Fase vegetatif porang merupakan fase yang penting untuk pertumbuhan dan perkembangan porang. Keberadaan gulma dapat mengganggu pertumbuhan porang. Tujuan penelitian ini mengidentifikasi keragaman spesies serta gulma dominan melalui analisis vegetasi dan analisis seed bank gulma pada lahan perkebunan tanaman porang fase vegetatif dengan pola tanam yang berbeda. Penelitian dilakukan bulan Januari sampai April 2024. Penelitian dilakukan dengan metode observasi meninjau langsung keberadaan gulma dengan analisis vegetasi dan analisis seed bank. Analisis vegetasi gulma dilakukan dengan metode kuadran 1 m x 1 m dengan titik pengambilan secara purposive sampling. Analisis seed bank dilakukan dengan menggali tanah pada setiap pola tanam. Tanah digali di lima titik setiap kuadran luasan 1 m x 1 m dengan kedalaman 0 sampai 10 cm sebanyak 32 sampel tanah. Gulma daun lebar mendominasi setiap pola tanam fase vegetatif berbeda. Gulma daun lebar paling dominan yang didapatkan pada analisis vegetasi yaitu Ageratum conyzoides. Hasil koefisien komunitas menujukan gulma pada pola tanam sama fase vegetatif berbeda memiliki kesamaan vegetasi yang besar. Dominasi pada Seed bank menunjukan spesies yang berbeda dengan hasil analisis vegetasi di lahan., Porang is a perennial plant that can be cultivated in various planting patterns and has several growth cycle phases. The vegetative phase of porang is crucial for its growth and development. The presence of weeds can interfere with the growth of porang. This study aims to identify species diversity and dominant weeds through vegetation analysis and weed seed bank analysis in porang plantations during the vegetative phase with different planting patterns. The research was conducted from January to April 2024. The study utilized observational methods to directly assess the presence of weeds, including vegetation analysis and seed bank analysis. Vegetation analysis of weeds was performed using a 1 m x 1 m quadrat method with purposive sampling points. Seed bank analysis involved soil excavation from each planting pattern. Soil samples were collected from five points within each 1 m x 1 m quadrat to a depth of 0 to 10 cm, totaling 32 soil samples. Broadleaf weeds dominated each planting pattern during the vegetative phase. The most dominant broadleaf weed identified in the vegetation analysis was Ageratum conyzoides. The community coefficient results indicated a high degree of similarity in weed vegetation across different cropping patterns within the same vegetative phase. However, the seed bank analysis revealed species that differed from those identified in the field vegetation analysis.
Keyword: ageratum conyzoides, keragaman komunitas, peperomia pellucida, torenia crustacea

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: Elektrodeposisi Film Tipis Semikonduktor Cu2ZnSnS4 (CZTS) pada Substrat Kaca ITO
Abstrak: Semiconductor Cu2ZnSnS4 (CZTS) thin film that can be used as absorber layers on solar cell module was made via electrodeposition method. CZTS thin film was electrodeposited on the surface of a silicate glass coated with a thin layer of indium tin oxide (ITO). Deposition process was done using potentiostatic mode at room temperature with a potential of 1.05 V for 30, 45, and 60 minutes, followed with annealing the film at 2 different temperatures, 500 ºC using furnace and 180 ºC using hot plate, both treatments for 45 minutes in N2/H2S atmosphere. The X-ray difractograms were analyzed using Match 2 program and showed that the CZTS thin films had kesterit crystalline structure, with a low percentage of CZTS phase. The thin film also contained secondary phases such as Cu2S, ZnS, and SnS. The obtained CZTS thin films had a thickness between 1.039 and 1.676 μm. Absorption study showed that the band gap energy of CZTS thin films which was annealed using furnace ranged from 1.50 to 1.52 eV, whereas that annealed using the hot plate was not observed. The band gap energy value showed that CZTS thin films can be used as sunlight absorber layers on solar cell. The formation of CZTS crystal film on this investigation was effectively performed using furnace annealing process at a temperature of 500 ºC with deposition time of 45 minutes.
Keyword: Thin film, Electrodeposition, Cu2ZnSnS4