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: Optimization of Spinach Fertilization Based on Soil Analysis Using Fertigation Through Drip Irrigation Systems
Abstrak: Pemupukan melalui irigasi tetes berdasarkan analisis tanah diharapkan dapat meningkatkan produktivitas bayam varietas Maestro. Penelitian dilaksanakan di Kebun Percobaan Cikarawang, Institut Pertanian Bogor dengan jenis tanah latosol, kandungan P-tersedia 3,9 ppm (sangat rendah), K-tersedia 40,2 ppm (sedang), C Organik 1,92%, dan pH 5,83. Penelitian ini bertujuan mendapatkan dosis rekomendasi pemupukan yang tepat untuk bayam berdasarkan hasil analisis tanah melalui sistem irigasi tetes dan menguji pengaruh potensi pupuk untuk dua kali tanam tanpa preplant dan fertigasi. Penelitian terdiri dari dua kali penanaman menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) faktor Tunggal dengan 5 ulangan dan 5 taraf pemupukan yaitu 0% X, 50% X, 100% X, 150% X, dan 200% X (X adalah rekomendasi berdasarkan program Ferads). Data dianalisis menggunakan uji-F dengan α 5% dan uji lanjut menggunakan analisis regresi. Hasil penelitian menunjukkan pada penanaman pertama didapatkan dosis optimum untuk bobot per bedeng marketable, bobot per bedeng total, perkiraan bobot panen per hektar marketable, dan perkiraan bobot panen per hektar total berturut-turut yaitu sebesar 151%, 133%, 135%, dan 132% dari dosis rekomendasi Ferads (219 kg N ha-1 , 274 kg P2O5 ha-1 , dan 149 kg K2O ha-1 ). Dosis 100% rekomendasi Ferads digunakan karena kenaikan hasil tidak signifikan meskipun diberikan dosis pupuk yang lebih tinggi. Dosis optimum tidak diperoleh pada penanaman kedua karena hasil analisis regresi tidak menunjukkan respon kuadratik. Residu pemupukan tidak mempengaruhi produksi bayam varietas Maestro secara keseluruhan sehingga analisis tanah perlu dilakukan di setiap musim tanam bayam., Fertilization through drip irrigation based on soil analysis is expected to increase the productivity of Maestro spinach varieties. The research was carried out at the Cikarawang Experimental Garden, Bogor Agricultural Institute with latosol soil type, P-available content of 3.9 ppm (very low), K-available 40.2 ppm (medium), C-Organic 1.92%, and pH 5 .83. This research aims to obtain the correct recommended dose of fertilizer for spinach based on the results of soil analysis using a drip irrigation system and testing the potential effect of fertilizer for two plantings without preplant and fertigation. The research consisted of two plantings using a single factor Randomized Complete Group Design (RKLT) with 5 replications and 5 levels of fertilization, namely 0% X, 50% X, 100% X, 150% X, and 200% X (X was a recommendation based on the Ferads program). Data were analyzed using F-test with α 5% and further testing using regression analysis. The results of the research showed that in the first planting, the optimum dose was obtained for weight per marketable bed, total weight per bed, estimated marketable harvest weight per hectare, and estimated total harvest weight per hectare respectively, namely 151%, 133%, 135%, and 132%. % of Ferads recommended dose (219 kg N ha-1 , 274 kg P2O5 ha-1 , and 149 kg K2O ha-1 ). The 100% dose recommended by Ferads was used because the increase in yield was not significant even though a higher fertilizer dose was given. The optimum dose was not obtained in the second planting because the results of the regression analysis did not show a quadratic response. Fertilizer residue does not affect the overall production of the Maestro spinach
Keyword: Ferads, fertigation, fertilizer dose, production, spinach

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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