Judul: Management of Tea Pruning (Camellia sinensis (L). O. Kuntze) at Wonosari Plantation, PT Perkebunan Nusantara XII, Malang, East Java
Abstrak: Teh merupakan komoditas unggul yang mempunyai peranan penting dalam perekonomian Indonesia. Pemangkasan merupakan salah satu kegiatan penting dalam menunjang produksi teh. Kegiatan magang bertujuan untuk mempelajari kegiatan budidaya teh secara teknis dan manajemen pemangkasan tanaman teh yang dilakukan di kebun. Magang dilaksanakan di Kebun Wonosari, PT Perkebunan Nusantara XII (Persero), Malang, Jawa Timur yang berlangsung dari bulan Januari 2020 hingga April 2020. Metode pengamatan yang dilakukan yaitu melalui pengamatan langsung di lapangan, mengikuti kegiatan teknis, serta mengumpulkan data sekunder yang didapatkan dari arsip kebun dan laporan manajemen. Hasil pengamatan menunjukkan semakin tinggi bidang petik maka tanaman teh akan semakin sulit untuk dilakukan pemetikan dan diameter bidang petik yang terlalu lebar dapat menyulitkan kegiatan pemetikan. Jenis pangkasan yang dilakukan Kebun Wonosari yaitu pangkasan produksi dan pangkasan jambul dengan gilir pangkas 3 tahun menggunakan metode manual dan mesin. Rencana jumlah areal yang akan dipangkas pada triwulan pertama sebesar 43,38 ha, namun realisasi luas lahan yang dipangkas yaitu 29,35 ha. Kapasitas tenaga kerja yang ditetapkan Kebun Wonosari sebesar 0,04 ha HOK-1 dan kapasitas tenaga kerja rata-rata pada triwulan pertama sebesar 0,05 ha HOK-1. Pertumbuhan tunas pada ketinggian tempat 950 m dpl lebih cepat jika dibandingkan dengan ketinggian tempat 1200 m dpl. Komposisi cabang yang terdapat di Kebun Wonosari antara lain cabang dengan diameter < 1 cm – 1,99 cm di Afdeling Wonosari (950 m dpl) sebesar 68,42% dan cabang dengan diameter > 2 cm sebesar 31,58%, sedangkan komposisi cabang dengan diameter < 1 cm – 1,99 cm di Afdeling Gebug Lor (1200 m dpl) sebesar 74,90% dan cabang dengan diameter > 2 cm sebesar 25,10%. Persentase kerusakan cabang sebesar 18,24% yang dilakukan oleh pekerja dengan lama kerja > 20 tahun lebih kecil daripada pekerja dengan lama kerja < 20 tahun yaitu 28,09%., Tea is one of valuable commodities which has an important role in Indonesia’s economy. Pruning is one of important activities in sustaining tea production. This internship aimed to study the technical and managerial activities in tea cultivation. Another objective was to study the tea pruning management in a plantation. The internship program was held in Wonosari Plantation, PT Perkebunan Nusantara XII (Persero), Malang, East Java from January 2020 until April 2020. The method for this internship includes direct plantation observation, participation in technical activities, and also by collecting secondary data through plantation records and management reports. The results shows that higher shoot diameter would make tea branch more difficult to prune, while a wide shoot diameter could increase the difficulty of pruning activity. Types of pruning used in Wonosari Plantation were production pruning and jambul pruning which cycles in 3 years using manual and mechanized methods. The planned total area to be pruned in the first quarter was 43,38 ha, but the actual area to be pruned was 29,35 ha. Labor capacity set in Wonosari Plantation was 0,04 ha HOK-1 with labor capacity set in first trimester averaging in 0,05 ha HOK-1. Shoot growth at an altitude of 950 m asl is faster than at 1200 m asl. Branch composition in Wonosari Plantation (950 m asl) is consist of 68,42% branches composed with
Keyword: bidang petik, jenis pangkasan, ketinggian tempat, presentase kerusakan

Judul: Pengelolaan Pemangkasan Tanaman Teh (Camellia sinensis (L.) O. Kuntze) di PT Perkebunan Nusantara XII, Malang, Jawa Timur
Abstrak: Pemangkasan dilakukan untuk mempertahankan kondisi bidang petik sehingga memudahkan dalam pekerjaan pemetikan dan mendapatkan produktivitas tanaman yang tinggi. Kegiatan magang bertujuan memperlajari dan memahami pengelolaan pemangkasan serta menganalisis aspek pemangkasan yang dilakukan di kebun. Metode pengamatan dilaksanakan secara langsung di lapang dengan mengikuti aspek teknis kebun, serta mengumpulkan data sekunder yang diperoleh dari arsip kebun. Hasil pengamatan menunjukkan pemangkasan pada Afdeling Wonosari dilakukan dengan dua cara, yaitu pemangkasan secara manual dengan menggunakan sabit dan gergaji, serta pemangkasan secara mesin dengan menggunakan mesin pemotong rumput 2 T atau 4 T dengan pisau gergaji berdiamater 10 inch (250 mm) x 2,7 mm x 25,4 mm x 100 T. Jenis pangkasan yang digunakan yaitu pangkasan produksi dengan gilir pangkas rata-rata berumur 36 bulan. Standar kerja pemangkas sebesar 0,04 HK-1. Cabang dengan diameter <1 cm masih banyak yang belum dipangkas terutama pada pemangkasan mesin. Pertumbuhan tunas dipengaruhi oleh karakteristik tanaman, jenis pangkasan, serta ketinggian tempat., Pruning is carried out to maintain the condition of the picking field so as to facilitate the picking work and obtain high plant productivity. The internship aims to learn and understand pruning management and analyze aspects of pruning in the garden. The observation method was carried out directly in the field by following the technical aspects of the garden, as well as collecting secondary data obtained from the garden archives. The results showed that pruning at Afdeling Wonosari was carried out in two ways, namely manual pruning using a sickle and saw, and mechanical pruning using a 2 T or 4 T lawn mower with a saw blade with a diameter of 10 inches (250 mm) x 2.7 mm x 25.4 mm x 100 T. The type of pruning used is production pruning with an average age of 36 months. The working standard of the trimmer is 0.04 HK-1. There are still many branches with a diameter of <1 cm that have not been pruned, especially in machine pruning. Shoot growth is influenced by plant characteristics, type of pruning, and altitude.
Keyword: alat pangkas, gilir pangkas, komposisi cabang, pertumbuhan tunas

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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