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: Responses in Growth and Production of Shallot (Allium cepa L.) on the  Application of Soil Ameliorant
Abstrak: Bawang merah merupakan salah satu komoditas pangan utama dan strategis yang produksi dan produktivitasnya sering tidak stabil. Salah satu upaya meningkatkan produktivitas bawang merah (Allium cepa L.) dengan memperbaiki kualitas kesuburan tanah dengan menambahkan pembenah tanah. Tujuan penelitian ini mengetahui pengaruh aplikasi bahan pembenah tanah ZeomicAgro dan Zeagro terhadap sifat kimia tanah, pertumbuhan, dan produksi tanaman bawang merah (Allium cepa L.). Penelitian dilakukan menggunakan rancangan acak kelompok (RAK) dengan empat perlakuan dan tiga ulangan. Perlakuan meliputi K0 = kontrol; ST (standar) = ZA 300 kg/ha, KCl 200 kg/ha, Urea 200 kg/ha, SP-36 200 kg/ha; P1 = Zeagro 200 kg/ha, ZA 200 kg/ha, KCl 150 kg/ha, Urea 150 kg/ha, SP-36 150 kg/ha; P2 = ZeomicAgro 200 kg/ha, ZA 200 kg/ha, KCl 150 kg/ha, Urea 150 kg/ha, SP-36 150 kg/ha. Zeagro merupakan pembenah tanah yang terbuat dari zeolit dan kapur sedangkan ZeomicAgro terbuat dari zeolit, kapur, dan bahan humat. Analisis sifat kimia tanah dilakukan pada tanah awal dan setelah panen pada 12 minggu setelah tanam (MST). Hasil analisis tanah menunjukkan bahwa pada perlakuan ZeomicAgro (P2) nyata meningkatkan N-total dan kejenuhan basa (KB), serta cenderung meningkatkan C-organik, P-tersedia, basa-basa dapat dipertukarkan, dan KTK dibandingkan standar dan perlakuan Zeagro. Perlakuan ZeomicAgro (P2) nyata meningkatkan tinggi tanaman, bobot basah, bobot kering, dan produktivitas dibandingkan standar dan Zeagro. Produktivitas tertinggi dicapai pada 6.79 ton/ha. Perlakuan ZeomicAgro dapat mengefisienkan penggunaan pupuk Urea, KCl, dan SP-36 hingga 25% dan pupuk ZA hingga 30% dari dosis standar., Shallots are one of the main and strategic food commodities whose production and productivity are often unstable. One of the efforts to increase the productivity of shallots (Allium cepa L.) by improving the quality of soil fertility by adding soil ameliorant. The purpose of this study is to determine the influence of the application of ZeomicAgro and Zeagro soil ameliorant agents on soil chemistry, growth, and production of shallot plants (Allium cepa L.). The research was conducted using a group random design (RAK) with four treatments and three repetitions. Treatment includes K0 = control; ST (standard) = ZA 300 kg/ha, KCl 200 kg/ha, Urea 200 kg/ha, SP-36 200 kg/ha; P1 = Zeagro 200 kg/ha, ZA 200 kg/ha, KCl 150 kg/ha, Urea 150 kg/ha, SP-36 150 kg/ha; P2 = ZeomicAgro 200 kg/ha, ZA 200 kg/ha, KCl 150 kg/ha, Urea 150 kg/ha, SP-36 150 kg/ha. Zeagro is a soil ameliorant made of zeolite and lime while ZeomicAgro is made of zeolite, lime, and humic acid. Analysis of soil chemical properties was carried out on the initial soil and after harvest at 12 week after planting. The results of soil analysis showed that in the ZeomicAgro (P2) treatment, it significantly increased total nitrogen and base saturation, tended to increase organic carbon, available phosphorus, exchangeable bases, and cation exchange capacity (CEC) compared to standard and Zeagro treatment. ZeomicAgro (P2) treatment significantly increased crop height, wet weight, dry weight, and productivity compered to standard and Zeagro treatment. The highest productivity was achieved at 6.79 tons/ha. ZeomicAgro treatment can increase the use of Urea, potassium chloride (KCl), and super phosphate-36 (SP-36) fertilizers up to 25% and fertilizer zwavelzure amonium (ZA)
Keyword: Humatic Substances, Lime, Soil Ameliorant, Zeolite, Shallots

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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