Judul: Potency and Effect of Organic Bio-fertilizer on Aren (Arenga pinnata Merr.) Stands in Sungkap Village, Central Bangka Regency
Abstrak: Aren memiliki nilai ekonomis dan ekologis tinggi karena hampir semua bagiannya dapat dimanfaatkan. Potensi aren cukup menjanjikan karena dapat hidup di berbagai kondisi tanah asalkan tercukupinya unsur hara. Penelitian bertujuan menduga potensi tegakan aren, produksi nira, pengaruh pupuk terhadap tegakan aren, dan rencana pengembangan aren di Desa Sungkap. Penelitian dilakukan dengan pemberian pupuk organik hayati merek Pupuk Ghaly Organik IPB dengan 45 sampel aren dan diuji dengan ANOVA. Hasil menunjukkan aren di Desa Sungkap menyebar di lahan budidaya dan liar yang keduanya menyebar secara berkelompok. Produksi nira yang tertinggi terjadi di lahan liar. Indikator tumbuhan dengan pemupukan seperti tinggi batang, lilit batang, jumlah daun, dan produksi nira terjadi secara signifikan, sedangkan pH dan brix nira tidak signifikan. Tutupan lahan kebun campuran diasumsikan sebagai habitat aren yang potensial, namun potensi tegakan aren masih belum optimal, sehingga perlu dilakukan budidaya dengan sistem agroforestri. Hasil penelitian dapat digunakan sebagai acuan dalam menduga potensi tegakan dan pengaruh pemupukan terhadap tegakan aren., Sugar palm has high economic and ecological value as almost all of its parts can be utilized. The potential of sugar palm in Sungkap Village is promising because it can thrive in various soil conditions as long as there is sufficient nutrient supply. The research aims to estimate the potential of sugar palm stands, sap production, the influence of fertilizer on sugar palm stands, and development plans for sugar palm in Sungkap Village. The research was conducted by applying organic bio-fertilizer branded Ghaly Organik IPB fertilizer to 45 samples of sugar palm and tested using ANOVA. The results indicate that sugar palm in Sungkap Village are distributed in both cultivated and wild areas, both of which are clustered. The highest sap production occurs in wild areas due to its habitat habitat. The highest sap production occurs in wild land. Plant indicators affected by fertilization such as trunk height, trunk girth, number of leaves, and sap production show significant changes, while pH and brix indicators do not. Mixed garden land cover is assumed to be a potential habitat, but the potential of sugar palm stands is still not optimal, thus cultivation with agroforestry systems are needed. The research results can be used as a reference for assessing the potential of stands and the effects of fertilization on sugar palm stands.
Keyword: budidaya, liar, potensi, pupuk, tegakan

Judul: Potential Estimation of Aren (Arenga pinnata (Wurmb) Merr.) in Cimantaja Resort, Mount Halimun Salak National Park
Abstrak: Aren memiliki kelimpahan yang dapat dijumpai di kawasan Resort Cimantaja, dimana seluruh tegakan yang ada di Resort Cimantaja merupakan tegakan yang tumbuh secara alami/liar, tanpa adanya kegiatan penanaman atau budidaya. Tujuan dari penelitian ini adalah untuk mengestimasi potensi tegakan aren terhadap regenerasi dan produktivitasnya, mengidentifikasi pola akses masyarakat dalam pemanfaatan aren, serta menganalisis saluran pemasaran gula aren. Metode yang digunakan dalam menduga potensi adalah wawancara dan inventarisasi tegakan. Hasil penelitian ini menunjukkan bahwa potensi tegakan dari tingkat tiang dan pohon belum menghasilkan cukup besar dengan persentase 84% merupakan pohon produktif. Pada inventarisasi tegakan, tingkat regenerasi menurun dari tingkat semai hingga pohon dengan kategori lestari. Produktivitas tegakan ditinjau dari kelas umur dan waktu, total potensi gula aren dari 4 desa yang terbesar adalah pada kelas umur 12-15 tahun sebesar 100.933 kg/tahun dengan jumlah 189 pohon, namun total produksi dari rentang umur 8-11 tahun memiliki persentase 56% dari total produksi. Akses pemanfaatan dilakukan di dalam dan di luar kawasan yang berdasarkan lahan garap dan status hak milik. Saluran tataniaga gula aren yang diwakili oleh Desa Cikarae Thoyybah yang menunjukkan bahwa saluran langsung (tingkat 0) memberikan keuntungan yang maksimal bagi petani. Kesimpulan dari penelitian ini adalah kelimpahan aren di Resort Cimantaja ini memiliki potensi jumlah, regenerasi serta produktivitas yang cukup baik dengan akses pemanfaatan yang telah diatur sesuai dengan tempat tumbuh tegakan serta saluran tataniaga yang cukup efisien yang ditunjukan dengan adanya saluran yang melibatkan pengumpul., Aren has an abundance that can be found in the Cimantaja Resort area, where all stands in the Cimantaja Resort are stands that grow naturally/wildly, without any planting or cultivation activities. The objectives of this study were to estimate the potential of aren stands for regeneration and productivity, identify regeneration access patterns in the use of aren, and analyze the marketing distribution of aren sugar. The methods used in estimating the potential were interviews and inventory of stands. The results of this study show that the potential of stands from the stake and immature tree levels is sufficiently large with a percentage of 84% being productive trees. In the stand inventory, the regeneration rate decreased from seedling to tree level with a sustainable category. Stand productivity in terms of age class and time, the total potential of palm sugar from 4 villages is the largest in the age class of 12-15 years at 100,933 kg/year with 189 trees, but the total production from the age range of 8-11 years has a percentage of 56% of the total production. Access to utilization based on cultivated land and private status is inside and outside the area. The palm sugar trade chain represented by Cikarae Thoyybah Village shows that the direct chain (level 0) provides maximum profit for farmers. The conclusion of this study is that the abundance of aren in Cimantaja Resort has the potential for number, regeneration and productivity that is sufficient, with access to utilization that has been regulated according to the place of growth of the stand and a sufficiently efficient trade chain that is shown by the involvement of middlemen.
Keyword: aren, pemanfaatan, potensial, produktivitas, tataniaga

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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