Judul: Saurophus Androgynus (L.) Merr. Response to Different Shades and Fertilizer Rates at Several Harvest Period
Abstrak: Katuk (Sauropus androgynus (L.) Merr.) is an indigenous plant that can be utilized as a leafy vegetable, food coloring, and herbal medicine. This research aims to determine the optimal shade intensity and fertilizer rate to enhance the growth and production of katuk plants. The experiment was conducted using a Randomized Complete Block Design (RKLT) Split plot design, with shade intensity as the main plot and fertilizer rate as the subplot. Shade intensity consisted of 4 levels: N0 (no shade), N1 (shade intensity 55%), N2 (shade intensity 65%), and N3 (shade intensity 75%). Fertilizer rate also consisted of 4 levels: P1 (480 Kg ha-1/3 times harvest), P2 (880 Kg ha-1/3 times harvest), P3 (1280 Kg ha-1 /3 times harvest), and P4 (1680 Kg ha-1/3 times harvest). The research results indicate that the optimum result for the katuk plant's cutting population is achieved at a shade intensity of >60%. Shade application affects the growth and production of katuk plants up to 20 WAP (3rd harvest). The use of 45% paranet is recommended to obtain optimum growth and production of katuk, compared to cultivation in full sun conditions or using paranet with a higher shade intensity. Fertilizer rates showed linear results, therefore this research has not yet been able to recommend the optimum fertilizer rate for katuk growth and production.
Keyword: fertilization, growth, indigenous vegetables, shade

Judul: Effect of Fertilization Dosage on Growth and  Production of Katuk (Sauropus androgynus) Cuttings Using Fertigation Through  Drip Irrigation
Abstrak: Keberadaan tanaman indigenous dapat menambah pilihan jenis sayuran sebagai konsumsi masyarakat. Salah satu tanaman yang masuk dalam tanaman indigenous adalah katuk. Untuk menunjang pertumbuhan tanaman katuk yang maksimal diperlukan adanya aplikasi pemupukan dan penyiraman yang efisien. Penelitian ini bertujuan mengetahui dosis pemupukan yang optimal pada budidaya katuk. Kegiatan penelitian dilaksanakan mulai bulan November 2022 hingga April 2023 di Kebun Percobaan Leuwikopo. Percobaan dilakukan dengan metode rancangan kelompok lengkap teracak sebanyak tiga kali ulangan. Penelitian terdiri dari faktor tunggal yaitu dosis pupuk N, P, dan K dengan lima taraf dosis (0%, 50%, 100%, 150%, 200%). Hasil penelitian menunjukkan bahwa pengaruh dari pemupukan tidak memberikan respon yang nyata, kecuali pada peubah tinggi cabang pada umur tanaman 10-13 MST. Meskipun tidak berpengaruh nyata, terdapat indikasi bahwa bobot basah, bobot daun, dan produktivitas total akan meningkat seiring peningkatan dosis pupuk yang diberikan., The existence of indigenous plants can increase the choice of vegetables for public consumption. One of the indigenous plants is katuk. To support the maximum growth of katuk plants, efficient fertilization and watering applications are needed. This study aims to determine the optimal dose of fertilization in katuk cultivation. Research activities were carried out from November 2022 to April 2023 at the Leuwikopo Experimental Garden. The experiment was conducted using a randomized complete group design method with three replications. The research consisted of a single factor, namely the dose of N, P, and K fertilizers with five dose levels (0%, 50%, 100%, 150%, 200%). The results showed that the effect of fertilization did not give a real response, except for the variable of branch height at plant age 10-13 weeks after planting. Although not significantly affected, there are indications that wet weight, leaf weight, and total productivity will increase as the dose of fertilizer applied increases.
Keyword: indigenous vegetables, inorganic fertilizer, productivity

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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