Judul: Fertilization Management and Monitoring of Oil Palm (Elaeis guineensis Jacq.) PreciPalm Demonstration Plots at PT Kalianusa, East Kutai, East Kalimantan
Abstrak: Kegiatan magang dilaksanakan selama empat bulan dimulai Januari hingga Mei 2023 di PT Kalianusa, Kutai Timur, Kalimantan Timur. Pemupukan yang baik dan benar menjadi aspek penting yang perlu diperhatikan dalam manajemen perkebunan kelapa sawit. Pengamatan dilakukan dengan mengamati konsep 5T (tepat jenis, dosis, waktu, cara, dan tempat) terhadap kegiatan pemupukan yang dilakukan di PT Kalianusa serta monitoring terkait sex ratio, jumlah buah hitam, dan produksi pada demplot PreciPalm. Hasil pengamatan menunjukkan proses pemupukan di PT Kalianusa telah dilakukan sesuai dengan standar perusahaan yang dilihat dari konsep 5T, kecuali pada aspek tepat dosis yang masih perlu ditingkatkan lagi. Presentase mutu kegiatan pemupukan yang didapatkan berdasarkan konsep 5T sebesar 82,94%. Rasio pupuk terhadap produksi TBS diamati dengan membandingkan produksi ton ha-1 tahun-1 dengan jumlah pupuk yang direalisasikan. Rasio pupuk terhadap produksi TBS pada blok kontrol sebesar 39,46 sedangkan pada blok PreciPalm sebsar 40,77., The internship was carried out for four months from January to May, 2022 at PT Kalianusa, East Kutai, East Kalimantan. Good and correct fertilization is an important aspect that needs to be considered in the management of oil palm plantations. Observations were done by observing the 5T concept (right type, dose, time, method, and place) of fertilization activities carried out at PT Kalianusa as well as monitoring related to sex ratio, number of black fruits, and production on PreciPalm demonstration plots. The results of the observation showed that the fertilization process at PT Kalianusa had been realized out in accordance with company standards as seen from the 5T concept, except for the right dose aspect which still needed to be improved. The percentage of quality of fertilization activities obtained based on the 5T concept is 82.94%. The ratio of fertilizer to FFB production was observed by comparing the production of ton ha-1 year-1 with the amount of fertilizer realized. The ratio of fertilizer to FFB production in the control block was 39.46 while in the PreciPalm block it was 40.77.
Keyword: pemupukan, konsep 5T, kelapa sawit, PreciPalm

Judul: Fertilization Management and Monitoring of Oil Palm (Elaeis guineensis Jacq.) PreciPalm Demonstration Plots on Peatland PT RSA, Inhil, Riau
Abstrak: Kegiatan magang dilaksanakan selama empat bulan dimulai 16 Januari hingga 14 Mei 2023 di Kebun Divisi I Belaras Barat, PT Riau Sawitindo Abadi, Kabupaten Indragiri Hilir, Riau. Efektif dan efisiensi perlu diperhatikan dalam pemberian pupuk kepada tanaman. Pengamatan pengaplikasian pemupukan dilakukan berdasarkan kaidah 5T (tepat jenis, tepat dosis, tepat waktu, tepat cara, dan tepat tempat) serta komponen produksi dan produktivitas pada blok percobaan PreciPalm. Hasil pengamatan menunjukkan proses pemupukan di Divisi I Belaras Barat telah memenuhi kaidah 5T sesuai standar perusahaan, kecuali pada tepat waktu pemupukan di tahun 2023 sedikit terjadi keterlambatan pemberian pupuk. Persentase keseluruhan berdasarkan kaidah 5T untuk pemupukan di Divisi I Belaras Barat sebesar 95,62%. Pengamatan produksi dan produktivitas dilakukan dengan menghitung jumlah dan bobot TBS di tiap bulan dan tahun, bobot janjang rata-rata tiap bulan, serta rasio pemupukan terhadap produksi TBS. Efisiensi pemupukan pada perlakuan PreciPalm sebesar 31,68% dan perlakuan kontrol sebesar 23,47%.
Keyword: gambut, kaidah 5T, kelapa sawit, pemupukan, PreciPalm

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.
Keyword: