Judul: The Effect of Multiple Doses of NPK 17-6-25 Fertilizer on
The Growth and Production of Cassava (Manihot esculenta Crantz)
Abstrak: GANI NURRAZAQ. Pengaruh Beberapa Dosis Pupuk NPK 17-6-25 terhadap Pertumbuhan dan Produksi Ubi Kayu (Manihot esculenta Crantz). Dibimbing oleh Suwarto. Tanaman ubi kayu merupakan komoditas umbi yang dimanfaatkan masyarakat sebagai produk konsumsi, pakan, dan bahan industri. Peningkatan pertumbuhan dan produksi ubi kayu dapat dilakukan dengan pemberian pupuk yang tepat dosis. Penelitian ini bertujuan mempelajari pengaruh dosis pupuk NPK (17-6-25) terhadap pertumbuhan dan produksi ubi kayu. Penelitian dilaksanakan pada bulan Oktober 2022 hingga Juni 2023 berlokasi di kebun percobaan cikabayan IPB, Dramaga, Bogor. Rancangan percobaan yang digunakan adalah rancangan kelompok lengkap teracak (RKLT) faktor tunggal dengan 6 perlakuan dan 4 ulangan disetiap perlakuan sehingga terdapat 24 satuan percobaan. Perlakuan dosis pupuk terdiri dari 6 taraf yaitu kontrol (P0), NPK standar (P1), dan NPK (17-6-25) dengan dosis 0,5 NPK (P2); 1,0 NPK (P3); 1,5 NPK (P4), dan 2,0 NPK (P5). Dosis NPK standar adalah 300 kg Urea, 200 kg SP-36, dan 200 kg KCl per hektar. Dosis pupuk NPK (17-6-25) berpengaruh pada pertumbuhan dan produksi umbi ubi kayu. Dosis pupuk NPK (17-6-25) sebesar 480 kg disertai dengan 119 kg Urea dan 120 kg SP-36 per hektar menghasilkan pertumbuhan tanaman dan produksi umbi lebih tinggi dibandingkan pupuk NPK standar dengan nilai RAE 116%. Pupuk majemuk NPK (17-6-25) dapat digunakan untuk menggantikan pupuk NPK standar dengan pupuk tunggal., The cassava plant is a tuber commodity the community uses as a consumer product, animal feed, and industrial material. The increasing growth and production of cassava can be helped with the right amount of fertilizer. This research aims to study the effect of multiple doses of NPK (17-6-25) fertilizer on the growth and production of cassava. The research was conducted from October 2022 to June 2023 at the Cikabayan experimental field IPB, Dramaga, Bogor. The experimental design used was a singlefactor complete randomized block design (RKLT) with 6 levels and 4 replications so there were 24 experimental units. The experimental dose treatment consisted of 6 levels that are a control (P0), Standard NPK (P1), and NPK (17-6-25) with 0,5 NPK (P2); 1,0 NPK (P3); 1,5 NPK (P4); and 2,0 NPK (P5) doses. NPK (17-6-25) doses affect the growth and tuber yield of cassava. The dose of 480 kg NPK (17-6-25) with 119 kg of Urea and 120 kg SP-36 per hectare produces higher plant growth and tuber production than standard NPK with 116% RAE. NPK (17-6-25) fertilizer can replace Standart NPK with a single fertilizer.
Keyword: pakan, bahan industri, pupuk majemuk, umbi

Judul: Effect of NPK 17-6-25 Fertilizer Dosage and  the Potential of Bacillus subtilis on Growth and Production of Sweet Potato (Ipomoea batatas L.)
Abstrak: Peningkatan kebutuhan ubi jalar tidak sebanding dengan produktivitas ubi jalar. Inovasi pemupukan majemuk yang secara khusus untuk produksi ubi jalar diperlukan dalam mendukung efisiensi budidaya. Pupuk NPK 17-6-25 sudah terbukti efektif terhadap pertumbuhan dan produksi ubi kayu, hal ini memberi peluang penggunaannya dalam pemupukan ubi jalar. Penelitian dilaksanakan di Kebun Percobaan Sawah Baru, Departemen Agronomi dan Hortikultura dan Laboratorium Pasca Panen, Institut Pertanian Bogor dari bulan Oktober 2023 hingga Februari 2024. Penelitian menggunakan rancangan kelompok lengkap teracak dua faktor yaitu varietas ubi jalar dengan 2 taraf Antin 3 dan Beta 1, serta dosis pemupukan NPK 17-6-25 0 kgha-1, 100 kgha-1, 200 kgha-1, 300 kg ha-1 dan 1 taraf pemupukan Bacillus subtilis 2,5 ml l-1. Hasil penelitian menunjukkan bahwa pertumbuhan vegetatif varietas Beta 1 lebih baik dari Antin 3. Perlakuan dosis pupuk NPK 17-6-25 100 – 300 kg ha-1 memberikan peningkatan hasil produksi dengan bobot umbi per petak sebanyak 21,54–24,81 kg dan bobot total umbi sampel sebanyak 6,39 kg. Kedua varietas ubi jalar memberikan respon yang berbeda terhadap perlakuan Bacillus subtilis. Dosis optimum pemupukan NPK 17-6-25 pada varietas Antin 3 sebanyak 235,35 kgha-1, dan untuk varietas Beta 1 sebanyak 176,75 kgha-1., The increasing demand for sweet potatoes is not proportional to their productivity. Innovation in compound fertilization specifically for sweet potato production are needed to support cultivation efficiency. NPK 17-6-25 fertilizer has proven effective for the growth and production of cassava, offering potentialfor its use in sweet potato fertilization. The research was conducted at the Sawah Baru Experimental Farm, Departement of Agronomy and Horticulture and Post–Harvest Laboratory, Bogor Agricultural University, from October 2023 to February 2024. The study used a two-factor randomized complete group design with sweet potato varieties (Antin 3 and Beta 1), and NPK 17-6-25 fertilizer doses of 0 kg ha-1, 100 kg ha-1, 200 kg ha-1, 300 kg ha-1, and one level Bacillus subtilis treatment at 2,5 ml l-1. The results showed that the vegetative growth of Beta 1 was better than that of Antin 3. Treatment with NPK fertilizer 17-6-25 doses of 100 300 kg ha-1 increased production yield, with tuber weights per plot ranging from 21,54 to 24,81 kg and total sample tuber weight of 6,39 kg. The two sweet potato varieties responded differently to Bacillus subtilis treatment. The optimum dose of NPK 17-6-25 fertilizer for the Antin 3 variety was 235,35 kg ha-1 and for the Beta 1 variety, it was 176,75 kg ha-1.
Keyword: produktivitas, antin 3, beta 1, umbi layak pasar

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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