Judul: Optimization of Planting Time for Three Varieties of Cayenne Pepper (Capsicum frustencens L.) in an Intercropping System with Sweet Corn (Zea mays L.)
Abstrak: Cabai rawit (Capsicum frutescens L.) adalah tanaman hortikultura yang memiliki nilai ekonomi tinggi. Dalam budidaya cabai, alih fungsi lahan menyebabkan penurunan luas panen. Salah satu cara untuk mengatasi masalah ini adalah dengan menerapkan pola tanam tumpangsari di lahan yang berada di bawah tegakan pohon atau dengan menanam tanaman cabai di lahan yang ditanam jagung. Mencari waktu tanam yang presisi dan varietas yang sesuai pada pola tanam tumpangsari merupakan tujuan dari penelitian ini. Penelitian ini menggunakan rancangan petak tersarang (nested design) dengan 2 faktor perlakuan yaitu waktu tanam dengan empat taraf yaitu kontrol: monokultur cabai rawit, 0, 4, 6 minggu setelah tanam jagung (MSJ) sebagai petak utama dan varietas cabai yaitu Bonita, Shadiva, dan Lobita sebagai anak petak. Pelaksanaan penelitian meliputi penyemaian, pengolahan lahan, penanaman, pemeliharaan, dan panen. Hasil dari penelitian ini menunjukan waktu tanam 0 MSJ berpengaruh signifikan pada peningkatan tinggi tanaman terutama pada varietas Shadiva dan menunjukan indikasi etiolasi akibat periode nanungan yang lebih lama dibandingkan waktu tanam lainnya. Nilai produktifitas pada waktu tanam 4 MSJ dan varietas Bonita, dan penurunan penyebaran gemini virus (Geminiviradae) pada 4 MSJ dibandingkan kontrol. Penggunaan waktu tanam yang sesuai dengan kombinasi varietas yang tepat dapat meningkatan nilai produktifitas serta menekan penyebaran penyakit tanaman dan dapat menjadi salah satu upaya untuk menerapkan pertanian berkelanjutan berbasis ramah lingkungan dan meningkatan penghasilan petani., Cayenne pepper (Capsicum frutescens L.) is a high economic value horticultural crop. In chili cultivation, land conversion leads to a decrease in the area under cultivation. One way to overcome this problem is to use intercropping on land under tree stands or to plant chili on land planted with maize. Finding a precise planting time and suitable varieties in intercropping patterns is the purpose of this study. This research utilized a nested design with two treatment factors, namely planting time with four levels: control (cayenne pepper monoculture), 0, 4, and 6 weeks after maize planting (MSJ) as the main plot and chili varieties, namely Bonita, Shadiva and Lobita as subplots. The research implementation includes sowing, soil preparation, planting, maintenance, and harvesting. The results of this study indicate a significant influence of planting time at 0 MSJ on the increase in plant height, particularly in the Shadiva variety, and suggest the possibility of etiolation resulting from prolonged shading periods compared to other planting times. The results indicated that the Bonita variety exhibited higher productivity values at the 4 MSJ planting time. In contrast, the control exhibited a higher incidence of the Gemini virus (Geminiviridae) at the same planting time. The optimal selection of planting time, in conjunction with the most suitable varieties, can enhance productivity and suppress the spread of plant diseases, thereby promoting sustainable agricultural practices that are environmentally friendly and increasing farmers' income.
Keyword: agroforestry, geminivirus, smart farming, sustainability, shading

Judul: The Effect of Giving Intensity of Shade at Several Stages on Yield of Cayenne Pepper (Capcisum frutescens L.)
Abstrak: Permasalahan dalam budidaya cabai pada saat panen raya adalah produksi cabai yang melimpah sementara harga yang rendah. Pemberian naungan adalah salah satu cara untuk menunda waktu panen dengan memanipulasi lingkungan tumbuh. Penelitian ini bertujuan mengetahui pengaruh naungan dan waktu pengaplikasiannya serta interaksi keduanya yang optimal untuk hasil dan penundaan waktu panen tanaman cabai rawit. Rancangan percobaan yang digunakan adalah split plot dengan rancangan lingkungan Rancangan Kelompok Lengkap Teracak (RKLT) 2 Faktor. Faktor pertama terdiri dari tujuh taraf naungan, yaitu tanpa naungan, naungan 25%, 30%, 50%, 60%, 90%, dan 100%. Faktor kedua terdiri dari empat waktu pengaplikasian naungan, yaitu pada saat tanaman berbunga, terbentuk bakal buah, buah hijau, buah merah. Percobaan dilakukan sebanyak 3 ulangan, sehingga terdapat 84 satuan percobaan. Setiap satuan percobaan terdiri dari 20 tanaman. Hasil penelitian menunjukkan bahwa perlakuan terbaik untuk hasil tanaman cabai rawit ditunjukkan oleh perlakuan naungan 25% dan waktu aplikasi pada saat buah merah. Perlakuan naungan 60% dengan waktu pengaplikasian pada saat tanaman berbunga memberikan umur panen tertinggi., The problem in chili cultivation at the time of harvest is the abundance of chili production while the price is low. Shading is one way to delay harvest time by manipulating the growing environment. This study aims to determine the effect of shade and time of application as well as the optimal interaction between the two for yield and delay in harvesting cayenne pepper. The experimental design used was a split plot with a 2-factor Complete Randomized Group Design (RKLT) environmental design. The first factor consists of seven levels of shade, namely no shade, 25% shade, 30%, 50%, 60%, 90%, and 100%. The second factor consisted of four times when the shade was applied, namely when the plants were flowering, ovule was formed, green fruit, and red fruit. The experiment was carried out in 3 replications, so there were 84 experimental units. Each experimental unit consisted of 20 plants. The results showed that the best treatment for the yield of cayenne pepper was indicated by a 25% shade treatment and application time when the fruit was red. The 60% shade treatment with application time at the time of flowering plants gave the highest harvest age.
Keyword: growing environment, growth, harvest, harvest age, 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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