Judul: Growth and Flower Yield of African Marigold (Tagetes erecta L.) under Different Pinching Frequencies and Fertilizer Types
Abstrak: Penelitian terkait pengaruh frekuensi pinching (setiap 2, 4 dan 6 hari) serta jenis pupuk (AB Mix dan NPK + Gandasil) terhadap pertumbuhan dan produksi marigold dilakukan di Kebun Percobaan CV. Benih Dramaga pada bulan Maret Juli 2023. Sebanyak tiga percobaan dilakukan secara terpisah berdasarkan bahan tanam, yaitu stek var. Sudamala Oranye 1 serta stek dan benih var. Maharani F1. Percobaan menggunakan stek dilakukan dengan Rancangan Kelompok Lengkap Teracak (RKLT) faktorial dua faktor yaitu frekuensi pinching serta jenis pupuk, benih dilakukan menggunakan RKLT dengan faktor jenis pupuk. Hasil penelitian menunjukkan bahwa frekuensi pinching berpengaruh nyata terhadap persentase tanaman berbunga, diameter serta bobot kuntum Sudamala Oranye 1. Jenis pupuk berpengaruh nyata terhadap persentase tanaman berbunga, warna daun dan mahkota bunga kedua varietas, persentase tanaman terserang layu bakteri Sudamala Oranye 1, serta jumlah tunas per minggu, total cabang baru, bobot segar bunga per tanaman, dan produktivitas Maharani F1 dari benih. Interaksi ditemukan pada jumlah tunas 5 dan 6 MST, total tunas baru per tanaman, dan diameter kuntum Sudamala Oranye 1. Pada kedua varietas, pinching 2 hari sekali menghasilkan komponen hasil tertinggi walaupun tidak berbeda nyata dengan frekuensi pinching lainnya. Sudamala Oranye 1 memiliki produksi tertinggi dengan pemberian AB Mix, sedangkan Maharani F1 pada aplikasi pupuk NPK + Gandasil., A research was conducted at CV. Benih Dramaga from March to July 2023 to study the effect of different pinching frequencies (every 2, 4 and 6 days) and fertilizer types (AB Mix and NPK + Gandasil) on marigold growth and flower yield. Three separate experiments were carried out based on planting material, namely cuttings of var. Sudamala Oranye 1, as well as cuttings and seeds of var. Maharani F1. The field experiments for cutting were carried out as factorial randomized block design (RCBD) with three replications in all possible combinations, while from seed used RCBD with seven replications and fertilizer types as the factor. The results revealed that pinching frequency significantly influenced the percentage of yielding plants, also diameter and fresh weight of individual flower of Sudamala Oranye 1. Fertilizer type significantly affected the percentage of yielding plants, leaf and flower petal color of both varieties, and the percentage of bacterial wilt-infected plants in Sudamala Oranye 1. Additionally, the number of shoots per week, total new shoots, fresh weight of flower per plant, and yield per hectare of Maharani F1 were significantly impacted. Interactions were observed in some growth parameters of Sudamala Oranye 1. In both varieties, pinching every 2 days produced the highest yield components, although not significantly different from other pinching frequencies. The highest Sudamala Oranye 1 flower yield was found with application of AB Mix, while NPK + Gandasil showed the highest yield in Maharani F1.
Keyword: AB Mix, Gandasil, Frekuensi pinching, NPK, Stek marigold, Pinching frequency, Shoot cuttings of marigold

Judul: Growth and Flowering Response of Two Clones of Marigold (Tagetes erecta L.) to Frequency of Pinching and Fertilization
Abstrak: Marigold (Tagetes erecta L.) merupakan tanaman herba hias yang berasal dari famili Asteraceae. Bunga marigold memiliki bentuk yang unik serta warna yang indah sehingga biasa digunakan sebagai tanaman hias dalam pot maupun sebagai karangan bunga. Marigold memiliki potensi untuk dikembangkan karena memiliki nilai ekonomis yang tinggi dan bunganya memiliki banyak kegunaan. Salah satu tindakan budidaya yang dapat meningkatkan pertumbuhan dan kualitas bunga adalah dengan perlakuan pinching dan pemupukan. Penelitian dilaksanakan pada bulan Desember 2022 - Juni 2023 di Kebun Percobaan CV. Benih Dramaga, Kecamatan Dramaga, Kabupaten Bogor. Penelitian ini menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) faktorial dengan taraf dua faktor yaitu frekuensi pinching dan frekuensi pemupukan AB mix. Faktor pertama adalah frekuensi pinching dari tiga taraf yaitu: 1 hari sekali (A1), 2 hari sekali (A2), dan 3 hari sekali (A3). Faktor kedua adalah frekuensi pemupukan dari dua taraf yaitu 2x/minggu (B1) dan 3x/minggu (B2). Pupuk yang digunakan pada penelitian ini adalah pupuk AB mix. Varietas marigold yang digunakan yaitu Sudamala Emas 1 sebagai tanaman utama dan Maharani sebagai tanaman pembanding. Hasil penelitian dari pengaruh frekuensi pinching, frekuensi pemupukan serta interaksi pinching dan pemupukan menunjukan pengaruh yang tidak berbeda nyata terhadap tinggi tanaman, jumlah bunga per tanaman, bobot bunga per tanaman, bobot bunga per kuntum, diameter bunga, dan Umur 50% berbunga., Marigold (Tagetes erecta L.) is an ornamental herbaceous plant from the Asteraceae family. Marigold flowers have a unique shape and beautiful colors so they are usually used as ornamental plants in pots or as flower bouquets. Marigolds have the potential to be developed because they have high economic value and the flowers have many uses. One of the cultivation measures that can improve the growth and quality of flowers is pinching and fertilizing. The research was carried out in December 2022 - June 2023 at the CV. Benih Dramaga, Perumahan IPB Alam Sinarsari Dramaga, Kecamatan Dramaga, and Kabupaten Bogor. This research used a factorial Randomized Complete Block Design (RCBD) with two factor levels, namely pinching frequency and AB mix fertilization frequency. The first factor was the frequency of pinching from three levels, namely: once a day (A1), once every 2 days (A2), and once every 3 days (A3). The second factor was the frequency of fertilization at two levels, namely 2x/week (B1) and 3x/week (B2). The fertilizer used in this research was AB mix fertilizer. The marigold variety used was Sudamala Emas 1 as the main variety and Maharani as the comparison. The results of the study of the effect of pinching frequency, fertilization frequency and the interaction of pinching and fertilization showed an effect that was not significantly different from plant height, number of flowers per plant, flower weight per plant, flower weight per flower, flower diameter, and 50% flowering time.
Keyword: marigold, pinching, pemupukan

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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