Judul: Optimization of Fertilization Dose in Eggplant Cultivation using Fertigation through Drip Irrigation
Abstrak: Terung banyak dibudidayakan di Indonesia namun masih memiliki angka produktivitas nasional yang cukup rendah. Peningkatan produktivitas dapat dilakukan dengan menyediakan unsur hara secara tepat melalui analisis tanah dan irigasi tetes. Penelitian bertujuan mendapatkan dosis optimum rekomendasi pemupukan tanaman terung berdasarkan uji analisis tanah Mehlich 1. Penelitian dilakukan di lahan terbuka Kebun Percobaan Cikarawang, Institut Pertanian Bogor selama bulan Juni sampai November 2022. Penelitian ini menggunakan rancangan kelompok lengkap teracak (RKLT) dengan satu faktor yaitu perlakuan 5 dosis pemupukan (0% X, 50% X, 100% X, 150% X, dan 200% X di mana X merupakan rekomendasi dosis pupuk Ferads) dengan 5 ulangan. Pemberian pupuk N, P, dan K melalui irigasi tetes mampu meningkatkan tinggi tanaman, diameter batang, jumlah buah, dan bobot buah, serta mempercepat waktu antesis, waktu buah masak, dan growing heat summation. Dosis optimum pemupukan untuk tanaman terung varietas Yuvita F1 di tanah latosol tercapai pada taraf 137,74% dosis pada taraf P-tersedia sangat rendah (Mehlich 1) dan K-tersedia sedang (Mehlich 1). Dosis pupuk rekomendasi Ferads 100% dapat digunakan karena peningkatan dosis pupuk optimasi tidak meningkatkan produksi secara signifikan., Eggplant is widely cultivated in Indonesia but still has a relatively low national productivity. Productivity can be increased by providing the right nutrients amount through soil analysis and drip irrigation. The objective of this study was to find optimum fertilization recommendation dose for eggplant based on Mehlich 1 soil analysis test. The study was conducted on open field at Cikarawang, Experimental Farm, Bogor Agricultural University from June to November 2022. This study used a randomized complete block design (RCBD) with one factor that consisted of 5 doses of fertilization (0% X, 50% X, 100% X, 150% X, and 200% X where X is the recommended fertilizer dose from Ferads) with 5 replications. Application of N, P, and K fertilizers through drip irrigation can increased plant height, stem diameter, number of fruits, and fruit weight, as well as speed up anthesis time, fruit ripening time, and growing heat summation. The optimum dose of fertilizer for eggplant variety Yuvita F1 on latosol soil was reached at the level of 137.74% from recommended dose at very low available P (Mehlich 1) and medium available K (Mehlich 1). 100% Ferads fertilizer recommendation dose can be used because increased fertilizer optimum dose does not significantly produce higher yield.
Keyword: dosis optimum, growing heat summation, Mehlich 1, optimum rate

Judul: Optimizing Fertilizer Dosages in Water Spinach Cultivation Using Fertigation Through Drip Irrigation
Abstrak: Peningkatan produktivitas tanaman kangkung varietas Bangkok-LP1 dapat dilakukan dengan cara pemberian dosis pupuk yang optimum berdasarkan analisis tanah secara fertigasi melalui irigasi tetes. Penelitian ini bertujuan untuk mengetahui rekomendasi dosis pupuk yang tepat untuk tanaman kangkung sehingga mencapai produktivitas yang maksimal. Penelitian dilakukan mulai bulan Juli sampai Oktober 2023 di Kebun Percobaan Cikarawang, Institut Pertanian Bogor, yang memiliki jenis tanah inceptisol dengan kandungan C-Organik 1,38%, P-Tersedia 5,5 ppm (sangat rendah), K-Tersedia 33,1 ppm (rendah), dan pH 6,03 (masam). Penelitian ini menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) dengan satu faktor yaitu perlakuan 5 dosis pemupukan 0%X, 50%X, 100%X, 150%X, dan 200%X, dengan X adalah dosis 219 kg N ha-1, 374 kg P2O5 ha-1, 187 kg K2O ha-1 dengan 4 ulangan. Hasil penelitian menunjukkan bahwa aplikasi pemupukan menggunakan fertigasi melalui irigasi tetes sampai 200% rekomendasi Ferads tidak memberikan pengaruh yang nyata pada pertumbuhan dan produksi kangkung varietas Bangkok-LP1. Produktivitas kangkung varietas Bangkok-LP1 mencapai 13,64 ton ha-1 pada penanaman pertama, sedangkan pada penanaman kedua dengan residu pemupukan menghasilkan 12,33 ton ha-1., Increasing the productivity of the Bangkok-LP1 variety of water spinach plants can be done by providing optimum fertilizer rate based on soil analysis using fertigation through drip irrigation. This research aims to determine the recommended fertilizer rate for water spinach plants to achieve maximum yield. The research was conducted from July to October 2023 at the Cikarawang Experimental Station, Bogor Agricultural University, which has an inceptisol soil type with a C-Organic content of 1,38%, P-Available 5,5 ppm (very low), K-Available 33,1 ppm (low), and pH 6,03 (acid). This study used a Randomized Completely Block Design (RCBD) with one factor, with 5 level fertilizer rate of 0%X, 50%X, 100%X, 150%X, and 200%X, where 219 kg N ha-1, 374 kg P2O5 ha-1, 187 kg K2O ha-1 with 4 replications. The results of the research showed that fertilization application using fertigation through drip irrigation up to 200% as recommended by Ferads did not have a significant effect on the growth and yield of the Bangkok-LP1 variety of water spinach. The productivity of the Bangkok-LP1 variety of water spinach reached 13.64 tons ha-1 in the first planting, while in the second planting with fertilizer residue it produced 12.33 tons ha-1.
Keyword: ferads

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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