Judul: Pengaruh pemberian kombinasi dosis pupuk dan bahan humat terhadap produksi tandan buah segar kelapa sawit (Elaeis guineensis): studi kasus PTPN VI unit usaha Rimbo Satu, Rimbo Dua, dan Batanghari, Effect of Combined Dosage of Fertilizer and Humic Substances on the Production of Oil Palm Bunches (Elaeis guineensis) (Case Study of PTPN VI Rimbo Satu, Rimbo Dua, and Batanghari Work Units).
Abstrak: Indonesia currently accounts for 47% of oil palm production from various oil palm estates around the world, making Indonesia the number one oil palm producer. Oil palm is one of Indonesia’s eminent agricultural commodities. In comparison to other oil producing plants, such as soybean, olive, coconut, and sunflower, oil palm is the most efficient oil producer. Oil palm can produce oil up to a maximum of 6-8 tons/ha/year. Meanwhile, other sources of oil crops only produce less than 2.5 tons/ha/year, far below the amount produced by oil palm. To obtain optimum production, the characteristics and factors affecting the process should also be optimized effectively and efficiently. One of the factors that influence the production is the fertilizer used during the process. Fertilization is one of the influential factors in planting. It affects plant growth, plant production, and the quality of the product. Fertilization is needed to obtain optimum production of bunches and to produce good quality oil. However, oil palm fertilization requires high cost. Therefore, it needs to be considered to achieve an efficient fertilization. One way to obtain an efficient and effective fertilization is by using humic substances
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Judul: Fertilization Management of Palm Oil (Elaeis guineensis Jacq.) in Negeri Lama Selatan Estate, PT Hari Sawit Jaya, Labuhanbatu, North Sumatera
Abstrak: Kelapa sawit merupakan tanaman perkebunan penting yang potensial untuk dibudidayakan. Pemeliharaan pada tanaman kelapa sawit khususnya pemupukan memerlukan biaya yang tinggi sehingga perlu diperhatikan peningkatan efisiensi dan efektivitas pada penerapannya. Kegiatan magang dilaksanakan di Kebun Negeri Lama Selatan, PT Hari Sawit Jaya, Labuhanbatu, Sumatera Utara yang berlangsung dari Januari-Mei 2022. Kegiatan magang bertujuan untuk mempelajari dan menganilisis sistem manajemen pemupukan kelapa sawit yang efektif dan efisien. Pengamatan pada manajemen pemupukan dilakukan pada penerapan kaidah 5T (tepat jenis, tepat dosis, tepat cara, tepat waktu dan tepat tempat). Berdasarkan hasil pengamatan, manajemen pemupukan di Kebun Negeri Lama Selatan sudah dijalankan dengan baik sesuai dengan standar yang ditetapkan oleh perusahaan. Penerapan sistem tempat pengeceran pupuk meningkatkan kualitas pemupukan dan mempermudah proses pelangsiran pupuk. Ketepatan dosis aplikasi pupuk pada pemupukan HGFB (High Fertilizer Borate) mencapai persentase 95.50% dan pada pemupukan MOP (Muriate of Potash) mencapai persentase dan 92.80%. Realisasi aplikasi pupuk sudah sesuai dengan rekomendasi waktu pemupukan. Cara pengaplikasian pupuk juga sudah baik, ratarata persentase tepat cara pemupukan HGFB dan MOP yaitu 95,50% dan 92,10%. Tempat pemupukan juga sudah diaplikasikan sesuai standar perusahaan, rata-rata jarak aplikasi pupuk dari pokok pada pemupukan HGFB dan MOP yaitu 54,88 cm dan 52,90 cm., Palm oil is an important plantation crop that has the potential to be cultivated. Maintenance of palm oil, especially fertilization, requires high costs, so its necessary to pay attention to increasing efficiency and effectiveness in its application. The internship was conducted on January to June 2022 at Negeri Lama Selatan Estate, North Sumatera. The internship activity aims to study and analyze an effective and efficient oil palm fertilization management system. Observations on fertilization management were carried out on the application of the 5T rule (right type, right dose, right method, right time and right place). Based on observations, fertilization management in Negeri Lama Selatan Estate has been carried out well according to the standards set by the company. The application of a fertilizer retailing system improves the quality of fertilization and simplifies the process of fertilizer distribution. The accuracy of fertilizer application dose on HGFB (High Grade Fertilizer Borate) fertilization reached the percentage of 95.5% and the MOP (Muriate of Potash) fertilization reached the percentage and 92.80%. The realization of fertilizer application is in accordance with the recommended time of fertilization. The method of applying fertilizer is also good, the average persentation of HGFB and MOP fertilization methods is 95.50% and 92.10%, respectively. The place of fertilization has also been applied according to company standards.
Keyword: cara pemupukan, efisiensi pemupukan, ketepatan pemupukan, fertilizer accurancy, fertilizer application, fertilizer efficiency

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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