Judul: Pemanfaatan Pupuk Kandang Ayam dan Fungi Mikoriza Arbuskula untuk Memperbaiki Pertumbuhan Bibit Jeruk Siam
Abstrak: The experiment was conducted to study the effects of manure, vasicular arbuscular michorizae (VAM) and their interaction on the growth of siam citrus seedling. The experiment was conducted at Kacinambun village, Karo, North Sumatera in Maret-Juli 2012. Experiment using Randomized Completely Block Design two factors. First factor was manure: 0 g, 250 g, and 500 g manure plant-1 and the second factor was VAM: 0 g, 5 g, 10 g, and 15 g VAM plant-1. The results showed that the manure at 500 g plant-1 showed better for number of branch, number of leaf, shoot dry weight, and leaf P concentration. VAM increase the percentage of root colonizations and leaf P concentration. Interaction of 250 g manure plant-1 and 15 g VAM plant-1 showed better result for the leaf P concentration.
Keyword: 

Judul: Pengaruh Inokulasi Mikoriza Arbuskular dan Pupuk Kandang Sapi terhadap Pertumbuhan Semai Kayu Putih (Melaleuca cajuputi) di Tanah Pascatambang Batu Kapur
Abstrak: Tanah pascatambang kapur memiliki kesuburan yang rendah sehingga proses revegetasi akan terhambat. Penambahan amelioran tanah dan pemilihan tanaman yang tepat diperlukan agar revegetasi berhasil dengan baik. Penggunaan Fungi Mikoriza Arbuskular (FMA) dan pupuk kandang sapi diharapkan dapat membantu pertumbuhan tanaman pada tanah pascatambang batu kapur. Tujuan penelitian ini adalah (1) menganalisis pengaruh interaksi FMA dan pupuk kandang sapi terhadap pertumbuhan tanaman kayu putih di tanah pascatambang kapur, (2) menganalisis dosis pupuk kandang yang optimal dalam meningkatkan pertumbuhan kayu putih. Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan dua faktor perlakuan (mikoriza dan pupuk kandang sapi). Hasil penelitian menunjukkan bahwa tidak ada pengaruh dari interaksi antara inokulasi FMA dengan pupuk kandang sapi. Pemberian FMA secara tunggal juga tidak berpengaruh secara nyata terhadap pertumbuhan semai kayu putih. Sementara faktor tunggal pupuk kandang sapi berpengaruh nyata pada pertumbuhan semai, dosis terbaik pupuk kandang sapi yaitu 15% yang dapat meningkatkan pertumbuhan tinggi dan diameter masingmasing sebesar 28,04% dan 38,41% dibanding tanaman kontrol., Post-mining soil has low fertility so that the revegetation process will be hampered. The addition of soil ameliorants and proper plant selection are necessary for successful revegetation. The use of Arbuscular Mycorrhizal Fungi (AMF) and cow manure is expected to help plant growth on post-limestone mining soil. The aims of this study were (1) to analyze the interaction effect of AMF and cow manure on the growth of eucalyptus plants in post-lime mining soil, (2) to analyze the optimal dose of manure in increasing eucalyptus growth. This study used a completely randomized design (CRD) with two treatment factors (mycorrhizae and cow manure). The results showed that there was no effect of the interaction between AMF inoculation with cow manure. Giving AMF alone also did not significantly affect the growth of eucalyptus seedlings. While the single factor of cow manure had a significant effect on seedling growth, the best dose of cow manure was 15% which could increase growth in height and diameter by 28,04% and 38,41%, respectively, compared to control plants.
Keyword: Eucalyptus, Mycorrhiza, Cow Manure, Post-mining Lime Soil

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.
Keyword: