Judul: Breaking the dormancy of shallots  (Allium cepa L.) with harvesting age and tubers cutting
Abstrak: Bawang merah merupakan tanaman hortikultura yang bernilai ekonomi tinggi dan strategis di Indonesia, karena banyak digunakan sebagai bumbu untuk sebagian besar menu masakan Indonesia, dan juga digunakan untuk tujuan pengobatan. Kendala dalam sistem pertanaman bawang merah adalah dormansi umbi, oleh karena itu informasi mengenai pematahan dormansi akan sangat bermanfaat bagi pola tanam mengenai ketersediaan umbi yang berkualitas sebagai bahan tanam. Peneltian ini bertujuan untuk mengetahui pengaruh umur sejak panen, pengaruh pemotongan umbi dan interaksi masa simpan serta pemotongan umbi terhadap dormansi umbi dan produksi bawang merah. .Percobaan dilaksanakan di Rumah Kaca Kebun Percobaan PKHT Pasir Kuda, Ciomas, Bogor, Jawa Barat, pada bulan Desember 2021 hingga Mei 2022. Rancangan percobaan yang dilakukan adalah Rancangan Acak Lengkap (RAL) faktorial dengan 2 faktor, yaitu umur sejak panen (2 minggu, 4 minggu, 6 minggu dan 8 minggu) dan pemotongan umbi (1/3 bagian dan tanpa pemotongan umbi). Hasil percobaan menunjukkan bahwa faktor pemotongan umbi dan umur sejak panen pada setiap minggu pengamatan tidak berpengaruh terhadap karakter jumlah tunas minggu ke 1 dan minggu ke 2., Shallots is a high economic value and strategic horticultural crop in Indonesia, since widelyuse as spice and seasoning for most Indonisian menu, and also use for medicinal purposes. Challenge in shallot planting system is bulb dormancy, therefore information regarding dormancy breaking will be very beneficial for planting pattern regarding availability of qualty bulb as pnating materials. This study was aimed valuate the effect of storage periode and bulb cutting on dormancy breaking and yield. The experimental design was a Completely Randomized Design (CRD) with 2 factorials, namely age from harvest 2 weeks, 4 weeks, 6 weeks, 8 weeks. week and cutting the tubers 1/3 part and without cutting the tubers. The experimental results showed that the factor of cutting tubers andage from harvest in each week of observation had no significant effect and also did not differ significantly between treatments. The experimental results showed that the factor of cutting tubers and age since harvest in each week of observation had no significant effect and also did not significantly different between treatments.
Keyword: horticulture, cropping pattern

Judul: Varietal Impact on Growth, Yield, and Water Requirements of Shallot (Allium cepa L. var. aggregatum) in Dryland Cultivation
Abstrak: Bawang merah (Allium cepa L. var. aggregatum) merupakan komoditas hortikultura yang mempunyai prospek pasar yang sangat baik sehingga termasuk ke dalam komoditas unggulan nasional. Penggunaan varietas yang merupakan salah satu cara untuk meningkatkan produktivitas bawang merah. Penelitian ini bertujuan mengetahui pengaruh dari penggunaan empat varietas bawang merah terhadap pertumbuhan, hasil panen, dan kebutuhan air pada tanaman bawang merah yang ditanam di lahan kering. Penelitian dilakukan di Kebun Percobaan Sawah Baru IPB, Dramaga, Bogor, Jawa Barat pada bulan Februari hingga April 2023. Penelitian dilakukan berdasarkan rancangan lengkap kelompok teracak (RKLT) dengan faktor tunggal. Perlakuan dalam penelitian ini adalah diamati adalah 4 varietas bawang varietas yaitu Bima Brebes, Bauji, Tajuk,dan SS Sakato. Hasil penelitian menunjukkan perlakuan varietas berpengaruh sangat nyata terhadap peubah tinggi tanaman pada 2 MST dan 3 MST, jumlah tunas pada 2 MST, 3 MST, 5 MST, dan 6 MST, jumlah daun pada 2 MST dan 4 MST, dan jumlah umbi. Seluruh varietas memberikan hasil yang baik untuk ditanam di lahan kering Bogor. Varietas Bauji merupakan varietas dengan proyeksi produktivitas per hektar tertinggi namun membutuhkan air yang lebih sedikit dari tanam hingga panen dibandingkan varietas Tajuk dan SS Sakato. Jumlah daun berpengaruh terhadap nilai evapotranspirasi, Shallot (Allium cepa L. var. aggregatum) is a horticultural commodity with excellent market prospects, thus being classified as a national superior commodity. The use of varieties is one way to enhance shallot productivity. This research aims to determine the influence of using four varieties of shallots on growth, harvest yield, and water requirements of shallot plants cultivated in dryland. The research was conducted at the Sawah Baru IPB Experimental Garden, Dramaga, Bogor, West Java, from February to April 2023. The research was based on a completely randomized block design with a single factor. The treatments in this study consisted of four observed shallot varieties: Bima Brebes, Bauji, Tajuk, and SS Sakato. The results of the research indicate that the variety treatment significantly influenced the plant height variable at 2 and 3 weeks after planting (WAP), the number of shoots at 2 WAP, 3 WAP, 5 WAP, and 6 WAP, the number of leaves at 2 WAP and 4 WAP, and the number of bulbs. All varieties showed good results for cultivation in dryland in Bogor Regency. The Bauji variety emerged as the most promising in terms of projected productivity per hectare, requiring significantly less water from planting to harvest compared to the Tajuk and SS Sakato varieties. The number of leaves influenced the evapotranspiration value.
Keyword: evapotranspirasi, curah hujan, produktivitas

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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