Judul: Application of Mycorrhiza Powder and Granules in Improving the Vegetative and Generative Phases of Shallots (Allium ascalonicum L.) in Regosol Dramaga
Abstrak: Pemanfaatan Regosol sebagai media tumbuh tanaman belum mendukung harapan produksi yang tinggi dengan kesuburan yang rendah dan hara mudah tercuci. Peningkatan produktivitas bawang merah dilakukan melalui upaya pemupukan yang tepat termasuk di dalamnya perbaikan dosis dan bentuk pupuk. Fungi mikoriza yang diinokulasi melalui pupuk hayati menginfeksi akar membentuk hifa eksternal yang meningkatkan kemampuan tanaman dalam penyerapan unsur hara, sehingga pertumbuhan dan perkembangan tanaman inang menjadi lebih cepat. Penelitian ini bertujuan menganalisis pengaruh pengaplikasian pupuk hayati mikoriza powder dan granul dengan taraf dosis pemupukan NPK berbeda dalam meningkatkan fase vegetatif dan generatif tanaman bawang merah pada Regosol Dramaga, menilai tingkat infeksi akar serta jumlah dan jenis spora, dan menganalisis sifat kimia tanah P-total dan P-tersedia. Metode eksperimental dilakukan menggunakan Rancangan Acak Lengkap (RAL) faktorial, petak utama jenis mikoriza dan anak petak dosis pupuk anorganik. Kombinasi perlakuan yang diuji sebanyak 12 diulang enam kali sehingga total terdapat 72 polybag. Mikoriza powder dan granul nyata meningkatkan tinggi tanaman, jumlah daun, dan jumlah umbi bawang merah paling baik. Mikoriza granul lebih efisien menghasilkan bobot basah dan kering umbi tanaman bawang merah paling berat, serta memberikan pengaruh nyata tertinggi pada nilai P-tersedia tanah mencapai 35,0 ppm dibandingkan kontrol sebesar 21,2 ppm., The use of Regosol has not yet supported expectation of high production with low fertility and easy-to-wash nutrients. Increasing productivity of shallots is carried out through proper fertilization, including dosage and fertilizer forms. Mycorrhizal infect the roots to form an external hyphae that increase plant's ability to absorb nutrients, so that the growth and development of the host plant becomes faster. This research aims to analyze application of mycorrhiza powder and granule biofertilizer with different NPK dosage levels in increasing the vegetative and generative phases of shallot in Regosol Dramaga, assessing level of root infection, number and type of spores, and analyzing chemical of P-total and P-available soils. Experimental method was carried out using Factorial Completely Randomized Design (CRD), the main plot of mycorrhizal type and the subsidiary plot of inorganic fertilizer dosage. Combination of treatments tested was 12, repeated six times, there were a total of 72 polybags. Application of powder and granule mycorrhizal increases the best height, number of leaves, and number of bulbs. Granule mycorrhizal are more efficient in producing wet and dry weight of the heaviest onion bulbs, as well as giving highest P-available soil reaching 35,0 ppm compared to the control of 21,2 ppm.
Keyword: bawang merah, mikoriza, regosol

Judul: fektivitas Pupuk Hayati terhadap Pertumbuhan dan Produksi Tanaman Bawang Merah (Allium ascalonicum).
Abstrak: Bawang merah merupakan salah satu komoditas strategis pertanian nasional dan memiliki peranan penting dalam perekonomian nasional. Pupuk hayati mengandung mikroorganisme tertentu yang dapat membantu meningkatkan ketersediaan unsur hara tertentu yang dibutuhkan untuk pertumbuhan dan produktivitas tanaman. Penelitian ini difokuskan pada efektivitas bakteri pengikat N2 dalam pupuk hayati yang dikombinasikan dengan pupuk N anorganik, serta pengaruhnya terhadap pertumbuhan dan produksi bawang merah. Percobaan menggunakan rancangan acak kelompok (RAK) faktor tunggal lima perlakuan, yaitu (T0) tanpa pupuk N sebagai kontrol, (T1) 100 % N, (T2) 75% N, (T3) 100% pupuk hayati dan 75% N dan (T4) 100% pupuk hayati dan 50% N, dan setiap perlakuan diulang tiga kali. Parameter yang diamati adalah tinggi tanaman, jumlah anakan, bobot segar tanaman, bobot kering tanaman, dan bobot umbi kering jemur. Data yang diperoleh dianalisis ragam pada tingkat kepercayaan 95 %, perlakuan yang berpengaruh nyata dilanjutkan dengan uji lanjut Tukey menggunakan software minitab. Efektivitas pupuk ditentukan dengan metode Relative Agronomic Effectiveness (RAE). Hasil analisis menunjukkan bahwa pemberian pupuk hayati dan pupuk N tidak ada yang berpengaruh nyata terhadap pertumbuhan dan produksi tanaman bawang merah., Shallots are strategic national agricultural commodities and have an important role in the national economy. Biofertilizers contain certain microorganisms that can increase the availability of certain nutrients needed for plant growth and productivity. This research was focused on the effectiveness of N2-fixing bacteria containing biofertilizers combined with inorganic N fertilizers and their effect on the development and production of shallot. This research used a completely randomized block design with five treatments, namely (T0) no N fertilizer as control, (T1) 100% N, (T2) 75% N, (T3) 100% biofertilizer and 75% N and (T4) 100% biofertilizer and 50% N, and each treatment was replicated three times. The parameters observed were plant height, number of tillers, fresh weight of the plant, dry weight, and dry weight of bulbs. The data was carried out to analyze the variance at the 95% confidence level, and Tukey's test using the Minitab software continued the treatment with a significant effect. The effectiveness of fertilizers was determined by the Relative Agronomic Effectiveness (RAE) method. The analysis results showed that the application of biofertilizers showed no significant effect on the growth and production of shallot.
Keyword: Bawang merah, Pupuk hayati., Biofertilizers, Shallot., Biofertilizers, Shallot

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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