Judul: Combination Effect of Biofertilizer, Organic Fertilizer, and NPK Fertilizer on Sweet Corn (Zea mays saccharata Sturt.) Yield
Abstrak: Jagung manis (Zea mays saccharata Sturt.) merupakan salah satu bahan pangan. Produktivitas jagung manis dapat ditingkatkan melalui teknologi pemupukan yang tepat. Tujuan penelitian ini adalah mempelajari pengaruh kombinasi pupuk hayati, pupuk organik, dan pupuk NPK terhadap hasil jagung manis. Penelitian disusun menggunakan rancangan acak lengkap teracak (RKLT) faktor tunggal yaitu kombinasi pupuk. Hasil penelitian menunjukkan perlakuan kombinasi pupuk berpengaruh nyata meningkatkan nilai brix dan diameter tongkol jagung manis. Pemupukan dengan pupuk hayati+organik+NPK 50% dosis memberikan nilai diameter tongkol tertinggi yaitu sebesar 5,1 cm, 10,9% lebih tinggi dibandingkan kontrol dan 6,25% lebih tinggi dibandingkan perlakuan pupuk hayati+organik tanpa pupuk NPK. Hal ini menunjukkan bahwa pemberian pupuk NPK masih diperlukan disamping aplikasi pupuk organik dan pupuk hayati. Pemupukan organik saja memberikan hasil tertinggi terhadap tingkat kemanisan jagung manis dengan nilai 16,8% brix, 15,9% lebih tinggi dibandingkan perlakuan pupuk NPK 100% dosis., Sweet corn (Zea mays saccharata Sturt.) is one of food source. Sweet corn productivity can be improved through right fertilization technology. The aim of this research was to study the effect of combination of biofertilizer, organic fertilizer, and NPK fertilizer on sweet corn productivity. Research used a Randomized Complete Block Design (RCBD) with single factor i.e. combination of fertilizer. The result showed that combination of fertilizer treatment had significant effect on the increase of ear diameter and sweetness level. Fertilization by biofertilizer+organic fertilizer+ NPK 50% doses improved ear diameter to 5.1 cm or 10.9% higher than the control treatment and 6.25% higher than fertilization by biofertilizer+organic no NPK fertilizer. It is shown that NPK fertilizer is needed beside organic fertilizer and biofertilizer. The organic fertilization only affect highest sweetness level with 16.8 % brix or 15.9% higher than NPK 100% doses treatment.
Keyword: brix, ear diameter, fertilization

Judul: Response of Fertilizing B and NPK to the growth of sweet  corn plants (Zea mays L. Saccharata) on Dramaga Inceptisols
Abstrak: Jagung manis (Zea mays L. Saccharata) adalah salah satu tanaman pangan dan bahan baku industri di Indonesia dan dunia. Peningkatan produktivitas jagung manis dapat dilakukan melalui optimasi pemupukan nitrogen (N), fosfor (P), kalium (K) dan boron (B) merupakan hara makro dan mikro esensial yang dibutuhkan tanaman jagung untuk dapat tumbuh dan berkembang serta berproduksi secara optimal. Penelitian ini bertujuan untuk mengetahui kandungan B dan NPK dalam tanah dan tanaman serta pertumbuhan dan perkembangan jagung manis sebagai respon dari kombinasi pemberian pupuk mikro B dan NPK pada Inceptisol Dramaga. Penelitian menggunakan Rancangan Acak Kelompok (RAK) dengan delapan perlakuan (B0S0, B0S1, B1S1, B2S1, B3S1, B1S2, B2S2, B3S2) yang terdiri dari empat taraf B (0, 9, 18, 27 kg/ha) dan tiga taraf NPK (0%, 75% dan 100% std). Perlakuan diulang kedalam empat kelompok menghasilkan 32 petak percobaan. Kombinasi pemberian pupuk B dan NPK signifikan meningkatkan B tersedia dalam tanah. Selain itu, pemberian pupuk B dan NPK meningkatka panjang daun, dan kadar B dalam tanaman serta mempercepat umur berbunga betina (silking). Pemberian 9-18 kg/ha B dan 75% NPK memiliki pengaruh positif yang relatif konsisten pada semua parameter agronomis yang diteliti. Perlu adanya penelitian lanjutan untuk melihat pengaruh pemberian pupuk B dan NPK terhadap produksi jagung manis pada tanah dengan kesuburan yang berbeda-beda, serta kombinasi waktu dan cara pemupukan B., Sweet corn (Zea mays L. Saccharata) is one of the staple crops and raw materials for the industry in Indonesia and globally. Increasing the productivity of sweet corn can be achieved through the optimization of nitrogen (N), phosphorus (P), potassium (K), and boron (B) fertilization, which are essential macro and micronutrients required for the optimal growth, development, and production of corn plants. This research aims to determine the content of B and NPK in soil and plants, as well as the growth and development of sweet corn in response to the combination of B and NPK micro-fertilizer application in Inceptisol Dramaga. The study utilized a Randomized Complete Block Design (RCBD) with eight treatments (B0S0, B0S1, B1S1, B2S1, B3S1, B1S2, B2S2, B3S2) consisting of four levels of B (0, 9, 18, 27 kg/ha) and three levels of NPK (0%, 75%, and 100% standard). The treatments were replicated into four blocks, resulting in 32 experimental plots. The combination of B and NPK fertilizer application significantly increased the available B in the soil. Additionally, B and NPK fertilization enhanced leaf length, and B content in the plants, as well as accelerate the female flowering age (silking). The application of 9-18 kg/ha B and 75% NPK showed a relatively consistent positive influence on all agronomic parameters studied. Further research is needed to examine the impact of B and NPK fertilizer application on sweet corn production in soils with varying fertility and explore the timing and methods of B fertilization
Keyword: Availability, boron, NPK, soil parameters, sweet corn

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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