Judul: Respon Tanaman Tomat (Lycopersicon esculentum Mill.) terhadap Dosis Pemupukan Berdasarkan Analisis Tanah yang Diapalikasikan melalui Fertigasi
Abstrak: enelitian ini membahas tentang tanaman tomat (Lycopersicon esculentum Mill.), salah satu tanaman hortikultura penting yang banyak dibudidayakan di seluruh dunia. Tanaman tomat memiliki nilai ekonomi dan gizi yang tinggi serta dapat tumbuh dengan baik di berbagai jenis tanah dan iklim. Dalam penelitian ini, fokus diberikan pada pengujian dosis pupuk optimal pada tanaman tomat dengan menggunakan mesin fertigasi. Mesin fertigasi digunakan untuk mengalirkan air dan pupuk secara presisi berdasarkan kebutuhan tanaman tomat. . Penelitian ini bertujuan untuk mengevaluasi pengaruh dosis pupuk urea, SP36, dan KCl dalam sistem fertigasi terhadap pertumbuhan tanaman tomat. Penelitian dilakukan dengan menggunakan lima dosis pupuk yang berbeda, yaitu 0%, 50%, 100%, 150%, dan 200% dari rekomendasi pupuk dosen. Pengumpulan data dilakukan melalui pengamatan pertumbuhan tanaman tomat, seperti tinggi tanaman, jumlah daun, dan berat buah. Percobaan dirancang menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) dan data dianalisis menggunakan regresi untuk mengetahui pengaruh dosis pupuk terhadap hasil panen tanaman tomat. Hasil dari penelitian ini dapat memberikan informasi tentang dosis pupuk terbaik yang dapat digunakan dalam sistem fertigasi untuk meningkatkan pertumbuhan dan hasil panen tanaman tomat. Dosis optimum pemupukan untuk tanaman tomat varietas Gustavi F1 di tanah latosol tercapai pada taraf 157,40% dosis pada taraf P-tersedia sangat rendah (Mehlich 1) dan K-tersedia rendah (Mehlich 1). Dosis pupuk rekomendasi Ferads 100% dapat digunakan karena peningkatan dosis pupuk optimasi tidak meningkatkan produksi secara signifikan., This research discusses tomato plants (Lycopersicon esculentum), one of the important horticultural crops that are widely cultivated worldwide. Tomato plants have high economic and nutritional value and can grow well in various types of soil and climates. In this study, the focus is given to testing the optimal fertilizer dose on tomato plants using fertigation machines. Fertigation machines are used to deliver water and fertilizer precisely based on the needs of tomato plants. This study aims to evaluate the effect of urea, SP36, and KCl fertilizer doses in the fertigation system on tomato plant growth. The study was conducted using five different fertilizer doses, namely 0%, 50%, 100%, 150%, and 200% of the recommended fertilizer dosage by the lecturer. Data collection was carried out through observations of tomato plant growth, such as plant height, leaf number, and fruit weight. The collected data were then analyzed using a Completely Randomized Design (CRD) to determine the effect of fertilizer doses on tomato plant growth. The results of this study can provide information on the best fertilizer dose that can be used in the fertigation system to improve the growth and yield of tomato plants. The optimum fertilization dosage for Gustavi F1 tomato plants in lateritic soil is achieved at a level of 157.40% of the dosage at very low available phosphorus (Mehlich 1) and low available potassium (Mehlich 1) levels. The recommended fertilizer dosage of Ferads 100% can be used because increasing the optimization fertilizer dosage does not significantly improve production.
Keyword: dosis, fertigasi, pertumbuhan, pupuk, tomat

Judul: Effect of Soil P and K Content on the Growth and Yield of Tomato (Lycopersicon esculentum) in Garut Andisols.
Abstrak: Tomat merupakan komoditas hortikultura yang banyak dibudidayakan dan dimanfaatkan di Indonesia. Produktivitas tomat dapat ditingkatkan dengan pendekatan teknologi budidaya seperti menggunakan teknologi irigasi dan pemupukan yang presisi. Penelitian ini menggunakan rancangan kelompok lengkap teracak (RKLT) dengan satu faktor berupa taraf status hara P dan K (rendah, sedang, dan tinggi) menggunakan perangkat uji tanah kering (PUTK). Analisis taraf hara P dan K pada tanah Andisol menggunakan PUTK terhadap tanaman tomat dapat digunakan. Hasil pada penentuan taraf hara P berbeda nyata pada hasil bobot kering tajuk, bobot kering total, jumlah buah total, dan bobot buah total. Taraf hara P tinggi menunjukkan rataan hasil produktivitas yang paling tinggi yaitu 307,59 gram/tanaman. Hasil pada penentuan taraf hara K menunjukkan perbedaan sangat nyata pada jumlah buah total dan berbeda nyata pada bobot kering tajuk, bobot kering total, dan bobot buah total. Taraf hara K tinggi menunjukkan rataan hasil produktivitas yang paling tinggi dari semua perlakuan yaitu 320,17 gram/tanaman., Tomato is a horticultural commodity that is widely cultivated and used in Indonesia. Tomato productivity can be increased by using cultivation technology approaches such as using irrigation technology and precise fertilization. This study used a completely randomized block design (RKLT) with one factor of P and K nutrient status levels (low, medium, and high) from the results of Garut Andisol soil testing using a perangkat uji tanah kering (PUTK). Analysis of P and K nutrient levels in Andisol soil using PUTK for tomato plants can be used. The results for determining the levels of P nutrients were significantly different in the results of shoot dry weight, total dry weight, total fruit number, and total fruit weight. The high level of P nutrient indicates the highest average yield of productivity, that is 307.59 gram/plant. The results for determining the K nutrient levels showed highly significant differences in the total fruit number and significantly different in shoot dry weight, total dry weight, and total fruit weight. The high K nutrient level showed the highest average yield of all treatments, that is 320.17 grams/plant.
Keyword: PUTK, Taraf Hara, Generatif, Vegetatif

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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