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: Comparison of Growth, Water Requirements, and Water Usage Efficiency between Five Shallot Varieties (Allium cepa L.).
Abstrak: Bawang merah (Allium cepa L.) merupakan kelompok sayuran rempah tidak bersubstitusi. Kebutuhan air tanaman dapat diperoleh melalui nilai evapotranspirasi. Penelitian ini bertujuan memperoleh perbedaan pertumbuhan, kebutuhan air tanaman, dan efisiensi pemakaian air pada masing-masing varietas. Penelitian dilaksanakan di Area Sawah di Desa Ngurensiti, Kecamatan Wedarijaksa, Kabupaten Pati, Provinsi Jawa Tengah dengan ketinggian ±7 meter di atas permukaan laut (m dpl) pada bulan Juli hingga September 2021. Penelitian ini dilakukan dengan menguji lima varietas bawang merah yaitu Bima Brebes (V1), Super Philip (V2), Tajuk (V3), Bauji (V4), dan Batu Ijo (V5) menggunakan Rancangan Kelompok Lengkap Teracak (RKLT). Bawang merah ditanam dengan jarak tanam 15 cm × 20 cm pada petak bedengan berukuran 3 m × 0,5 m. Hasil penelitian diperoleh perlakuan varietas berpengaruh nyata terhadap pertumbuhan tinggi tanaman dan jumlah daun pada kelima varietas. Varietas Tajuk memiliki jumlah daun terbanyak dan memiliki nilai evapotranspirasi/kebutuhan air tertinggi, sedangkan varietas Batu Ijo sebaliknya. Perlakuan varietas tidak berpengaruh nyata terhadap efisiensi pemakaian air. Varietas Super Philip merupakan varietas terbaik menurut hasil analisis data panen., Shallots (Allium cepa L.) are a non-substitute herb. Plant water requirements can be obtained through the value of evapotranspiration. This research aims as well as to obtain growth differences, plant water requirements, and water use efficiency for each varieties. The research was conducted in a rice field area in Ngurensiti Village, Wedarijaksa District, Pati Regency, Central Java with an altitude of ±7 meters above sea level (m asl) from July to September 2021. This research was conducted by testing five shallot varieties, namely Bima Brebes (V1), Super Philip (V2), Tajuk (V3), Bauji (V4), and Batu Ijo (V5) using a Randomized Complete Block Design (RCBD). Shallots were planted with a spacing of 15 cm × 20 cm in a bed plot measuring 3 m × 0.5 m. The results showed that the varieties treatment had a significant effect on the growth of plant height and number of leaves in the five varieties. Tajuk has the highest number of leaves and has the highest evapotranspiration/water requirement value, while Batu Ijo is the opposite. Varietal treatment has no significant effect on water use efficiency. Super Philip is the best varieties according to the results of harvest analysis.
Keyword: efficiency, evapotranspiration, shallot, water requirements

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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