Judul: The Management of Tea Harvesting in Gambung Tea Plantation and Crystal Guava Seedlings Cultivation at th Agribusiness and Technology Park
Abstrak: Komoditas perkebunan dan hortikultura yang saat ini digemari dan banyak beredar di masyarakat adalah teh dan jambu kristal. Dibutuhkan upaya untuk peningkatan produksi kedua komoditas tersebut. Peningkatan produksi teh dapat dilakukan dengan pemilihan klon unggul dan teknik pemetikan yang tepat, sedangkan jambu kristal dapat dilakukan dengan grafting untuk produksi bibit. Kegiatan magang dilaksanakan di Pusat Penelitian Teh dan Kina Gambung, dan di Kebun Jambu Kristal Agribusiness and Technology Park yang dilaksanakan berturut-turut pada bulan Januari hingga April 2022 dan Oktober 2022 hingga Januari 2023. Metode yang digunakan pada kedua kegiatan magang adalah metode langsung dan tidak langsung. Metode langsung dilakukan dengan pengambilan data di lapang secara langsung berupa aspek teknis, sedangkan metode tidak langsung dilakukan dengan pengambilan data dari perusahaan. Klon GMBS-5 memberikan hasil pertumbuhan yang lebih tinggi dibandingkan dengan klon GMBS-1; GMBS- 3; GMBS-4; dan GMB-7, sementara teknik pemetikan tidak berpengaruh nyata terhadap laju pertumbuhan klon. Pelaksanaan pemetikan teh di PPTK Gambung belum sepenuhnya sesuai dengan standar perusahaan, sehingga diperlukan pengawasan mandor yang lebih ketat. Kegiatan magang di Kebun ATP Cikarawang telah meningkatkan wawasan dan keterampilan dalam praktik dan kerja lapang dalam pengelolaan tanaman jambu kristal. Grafting yang dilakukan oleh pihak ATP dan penulis pada periode pengamatan telah menghasilkan bibit dengan persentase keberhasilan yang tinggi, yaitu 94,12% dan 88,24% bibit hidup, 70,59% dan 61,76% bertunas, serta 58,82% dan 52,94% pecah tunas. Selain itu, juga terjadi peningkatan tinggi serta diameter bibit walau tidak berbeda nyata., Tea and crystal guava are some of most favorable horticulture commodities nowadays. An effort to increase production on both commodities is needed. Tea production can be increased by selecting superior clone and using the right picking techniques while crystal guava production can be increased by using grafting for seedlings production. Internship were held on PPTK Gambung and ATP’s crystal guava plantation from January to April 2022 and October 2022 to January 2023. Direct and indirect methods were used. Direct method was conducted by collecting field’s data, while indirect method was conducted by collecting data from company. In terms of growth, GMBS-5 clone gives a higher result compared to GMBS-1; GMBS-3; GMBS-4; and GMB-7, while picking techniques didn’t give any significant difference toward clone’s growth rate. Tea picking in PPTK gambung hasn’t met company’s standard so that stricter supervision is needed. The internship activities at the ATP Cikarawang Farm have improved insights and skills in practice and fieldwork in the management of crystal guava plants. Grafting that conducted by ATP and the author during the observation period have produced seedlings with high percentage of success with 94.12% and 88.24% on surviving, 70.59% and 61.76% on germinating, and 58.82% and 52.94% on bud breaking. Increased in seedlings’ height and diameter were also observed though they didn’t give a significantly different result.
Keyword: batang atas, batang bawah, tenaga kerja, laju pertumbuhan, teknik petik

Judul: The Effect of PGPR and Bending on the Flowering and Fruiting of Guava (Psidium guajava L.) Var. Crystal
Abstrak: Jambu Jambu biji (Psidium guajava L.) varietas ‘Kristal’ merupakan salah satu varietas jambu biji yang paling unggul di Indonesia. Produksi dan konsumsi tahunan jambu biji ‘Kristal’ terus mengalami peningkatan, sehingga diperlukan peningkatan pembungaan dan pembuahan untuk menjaga stabilitas produksi. Pupuk anorganik biasa digunakan tetapi memiliki dampak negatif, sehingga perlu digunakan pupuk organik. Penelitian ini bertujuan untuk meningkatkan pembungaan dan pembuahan jambu biji ‘Kristal’ melalui aplikasi pelengkungan cabang dan pupuk hayati PGPR. Penelitian ini dilakukan dari Februari 2024 hingga April 2024 di Kebun Penelitian Cikabayan, Institut Pertanian Bogor. Penelitian ini menggunakan rancangan petak terbagi (split plot) menggunakan dua faktor. Faktor pertama adalah PGPR dan yang kedua adalah pelengkungan. Hasil penelitian menunjukkan bahwa pelengkungan secara signifikan meningkatkan pertumbuhan vegetatif (jumlah tunas dan jumlah tunas vegetatif) dan generatif (jumlah bunga dan buah). Pemberian PGPR secara signifikan meningkatkan perkembangan generatif dalam bentuk berat buah total. Pelengkungan dan pemberian PGPR tidak memberi pengaruh signifikan terhadap kualitas fisik dan kualitas internal buah., Guava (Psidium guajava L.) var. crystal is one of the most superior guava varieties in Indonesia. The annual production and consumption of Crystal guava continue to increase, so it is necessary to enhance flowering and fruiting to maintain production stability. This research aims to increase the flowering and fruiting of Crystal guava through the application of branch bending and PGPR biofertilizer. The study was conducted from February 2024 to April 2024 at the Cikabayan Research Station, Bogor Agricultural University. This research used a split-plot design with two factors. The first factor is PGPR biofertilizer and the second is bending. The results showed that bending significantly increased vegetative growth (number of shoots and vegetative shoots) and generative growth (number of flowers and fruits). The application of PGPR significantly increased generative development in the form of total fruit weight. Bending and the application of PGPR did not significantly affect the physical quality and internal quality of the fruit.
Keyword: pertumbuhan vegetatif, hortikultura, pupuk organik, perkembangan generatif, 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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