Judul: Frequency of Organic Fertilization Determines the Growth and Yield of Okra (Abelmoschus esculentus L. Moench.).
Abstrak: Tanaman okra populer di negara Asia karena memiliki banyak manfaat dari mulai daun muda, batang, kuncup bunga, polong muda sampai biji dari buah okra. Sebagai sayuran fungsional, produk pertanian memiliki nilai tambah jika dibudidayakan secara organik. Okra yang dibudidayakan secara organik memerlukan panduan pemupukan karena pembentukan bunga dan buah okra tidak berlangsung serentak. Panduan yang sudah tersedia untuk pemupukan tanaman okra, yaitu dilakukannya pemupukan anorganik secara bertahap. Pengujian pemupukan okra menggunakan pupuk kandang kambing susulan tidak memperbaiki pertumbuhan dan produksi buah okra. Oleh karena itu perbaikan teknik aplikasi pupuk kandang ayam dengan pengaturan frekuensi pemupukan diharapkan dapat menghasilkan teknologi budidaya okra yang lebih baik. Penelitian ini dilaksanakan pada September - Desember 2022 di kebun percobaan organik IPB di Cikarawang, Bogor. Penelitian ini menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) dengan satu faktor yaitu frekuensi pemupukan yang terdiri dari tanpa pemupukan, satu, dua, dan tiga kali pemupukan dengan dosis tunggal 18 ton pupuk kandang ayam ha-1. Hasil penelitian menunjukkan bahwa pemberian pupuk kandang ayam sebanyak 18 ton ha-1 yang diberikan secara sekaligus (2 minggu sebelum tanam) meningkatkan secara cepat karakter morfologi dan fisiologi tanaman okra di awal pertumbuhan. Pemberian pupuk secara bertahap yaitu 2 minggu sebelum tanaman dan 4 minggu setelah tanam meningkatkan tinggi tanaman 11 MSP, jumlah daun 11 MSP, kadar K daun, jumlah polong, bobot polong dan paling baik dalam meningkatkan produktivitas polong muda tanaman okra., The okra plant is popular in Asian countries because it has many benefits, from young leaves, stems, flower buds, young pods to seeds from okra fruit. As functional vegetables, agricultural products have added value if they are cultivated organically. Organically cultivated okra requires fertilization guidance because the formation of okra flowers and fruit does not take place simultaneously. Guidelines that are already available for fertilizing okra plants, namely carrying out inorganic fertilizers in several stages. Testing of okra fertilization using goat manure did not improve the growth and fruit production of okra. Therefore, improving the chicken manure application technique by adjusting the frequency of fertilization is expected to produce better okra cultivation technology. This research was conducted in September - December 2022 at the IPB organic experimental field in Cikarawang, Bogor. This study used a Randomized Completely Block Design (RCBD) with one factor, namely the frequency of fertilization which consisted of no fertilization, one, two and three times of fertilizing with a single dose of 18 tons chicken manure ha-1. The results showed that the application of chicken manure as much as 18 tons ha-1 which was given at once (2 weeks before planting) rapidly increased the morphological and physiological characters of okra plants at the beginning of growth. Gradual application of fertilizer i.e. 2 weeks before planting and 4 weeks after planting increased plant height by 11 WAP, number of leaves by 11 WAP, leaf K content, number of pods, pod weight and was the best in increasing the productivity of young pods of okra plants
Keyword: hara daun, okra hijau, pemupukan bertahap, polong muda, hara daun, okra hijau, pemupukan bertahap, polong muda

Judul: Frequency of Goat Manure Aplication for Red Okra Fruit (Abelmoschus esculentus L. Moench) Production
Abstrak: Okra merupakan komoditas sayuran yang mempunyai banyak manfaat karena kandungan serat larut yang tinggi dan senyawa bersifat antioksidan. Budidaya okra umumnya dilakukan dengan cara memberikan pupuk anorganik secara bertahap. Belum ada acuan untuk membudidayakan okra dengan pupuk organik saja. Penelitian ini bertujuan mengetahui produksi buah okra dengan perbedaan cara pemberian pupuk organik saja. Penelitian dilakukan bulan Januari sampai Juni 2019 di Kebun Percobaan IPB di Leuwikopo, Darmaga, Bogor. Percobaan menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) satu faktor terdiri dari 3 ulangan. Perlakuan dalam penelitian adalah tanpa pupuk, pupuk organik sekali, pupuk organik bertahap dan pupuk anorganik bertahap sebagai pembanding. Hasil penelitian menunjukkan pemberian pupuk organik sekali nyata meningkatkan tinggi dan diameter tanaman, jumlah daun tanaman, bobot basah dan kering tanaman, indeks luas daun, bobot polong total, bobot polong muda per petak, bobot polong tua per petak, serta NPK buah okra merah. Produktivitas polong total dengan pemberian pupuk organik sekali tidak nyata lebih tinggi dari yang mendapat pupuk organik bertahap, namun nyata lebih rendah dari yang mendapatkan pupuk anorganik secara bertahap. Kata kunci: pemupukan bertahap, pupuk anorganik, pupuk kandang kambing, pupuk organik, Okra is a vegetable commodity that is rich in antioxidants and has many benefits due to its high content of soluble fiber and antioxidant compounds. Okra cultivation is generally done by giving inorganic fertilizers gradually. There is no reference for cultivating okra with organic fertilizer alone. This study aims to determine the production of okra fruit with differences in the frequency of organic fertilizer only. The experiment was conducted from January to June 2019 at the IPB Experimental Garden in Leuwikopo, Darmaga, Bogor. The experiment used a one-factor randomized complete block design with 3 replications. The treatments consisted of: without fertilizers, single application of organic fertilizers, gradual organic fertilizers, and gradual inorganic fertilizers. The results showed that the single application of organic fertilizer had a significant highest of values of plant height and diameter, number of plant leaves, plant fresh and dry weight, leaf area index, total pod weight, young pods weigh per plot, old pods weight per plot, and NPK nutrient content of red okra fruit. The yield of okra with single application of organic fertilizer did not significantly higher than that with single application of organic fertilizer, but significantly lower than yield of okra with inorganic fertilizer gradually applied. Keywords: gradual fertilization, goat manure, inorganic fertilizer, organic fertilizer
Keyword: gradual fertilization, goat manure, inorganic fertilizer, organic fertilizer

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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