Judul: Effectiveness Test of Mycorrhizzal Biofertilizer on Akasia (Acacia mangium Willd.) in Nursery
Abstrak: Akasia (Acacia mangium Willd.) merupakan salah satu jenis tanaman yang memiliki prioritas unggul dalam pengembangan hutan tanaman indsustri (HTI) di Indonesia, salah satunya dalam kegiatan reboisasi pada potensi kawasan hutan kurang produktif. Pemberian pupuk hayati dapat menjadi salah satu alternatif dalam memperbaiki, meningkatkan, dan mempertahankan kualitas tanah sehingga mampu menunjang pertumbuhan, hasil, serta kualitas berbagai tanaman. Penelitian ini bertujuan mengetahui pengaruh pupuk hayati mikoriza terhadap pertumbuhan tanaman akasia di nursery, menganalisis infeksi akar dan jenis spora disebabkan mikoriza, serta mengkaji pengaruh pemberian pupuk hayati mikoriza terhadap sifat kimia dan biologi tanah. Penelitian ini menggunakan rancangan acak lengkap (RAL) faktor tunggal dengan enam taraf perlakuan dan dua belas ulangan, sehingga satuan percobaan adalah 72 polybag. Perlakuan pengujian pupuk hayati berdasarkan Peraturan Menteri No. 1 Tahun 2019 antara lain kontrol (tanpa pupuk NPK dan pupuk hayati); 1 NPK; 1 pupuk hayati; 1 NPK standar + 1 pupuk hayati; 3/4 NPK + 1 pupuk hayati; serta 1/2 NPK + 1 pupuk hayati. Perlakuan kombinasi 1 NPK standar + 1 pupuk hayati memberikan hasil pertumbuhan paling baik pada parameter tinggi, jumlah daun, dan berat kering tajuk (BKT), sedangkan kombinasi 1/2 NPK + 1 pupuk hayati paling baik pada parameter diameter batang dan berat kering akar (BKA). Nilai Relative Agronomic Effectiveness (RAE) pada perlakuan 1 NPK + 1 pupuk hayati menunjukkan hasil yang paling efektif secara agronomi. Pemberian mikoriza mampu membentuk kolonisasi akar sebesar 60% dan jenis spora yang paling banyak ditemukan berasal dari jenis Acaulospora sp. dan Glomus sp. Total populasi mikroba dan respirasi tanah tertinggi terdapat pada perlakuan 1 NPK + 1 pupuk hayati. Pemberian mikoriza pada tanaman akasia menunjukkan adanya peningkatan ketersediaan fosfor tersedia dan fosfor total dalam tanah., Acacia (Acacia mangium Willd.) is one of the plant species that has a high priority in the development of industrial plantations in Indonesia. High priority in the development of industrial plantation forests in Indonesia, one of which is in reforestation activities on potential underdeveloped productive forest areas. The application of biological fertilizers can be an alternative in improving, improve and maintain soil quality so that it can support growth, yield, and quality of various plants. This study aims to determine the effect of mycorrhizal biofertilizer on acacia plant growth in the nursery, analyze root infection and spore types caused by mycorrhiza in acacia plants in the nursery, and examine the effect of mycorrhizal biofertilizers on the chemical and biological properties of soil. This study used a single-factor completely randomized design (CRD) with six levels of treatments and twelve replications, so the experimental unit was 72 polybags. Biological fertilizer testing treatment is based on Ministerial Regulation no. 1 of 2019, including control; 1 standard NPK (15-15-15); 1 biofertilizer; 1 standard NPK + 1 biofertilizer; 3/4 NPK + 1 biofertilizer; and 1/2 NPK + 1 biological fertilizer. The combination treatment of 1 standard NPK + 1 biological fertilizer gave the best growth results in the parameters of height, number of leaves, and shoot dry weight (BKT), while the combination of 1/2 NPK + 1 biological fertilizer was the best in the parameters of stem diameter and root
Keyword: root infection, microbes, relative agronomic, Regosol

Judul: Penggunaan Rhizobium Dan Mikrob Pelarut Fosfat (MPF) Untuk Memperbaiki Pertumbuhan Bibit Akasia (Acacia mangium dan Acacia crassicarpa)
Abstrak: The increasing of paper raw material requirement is caused by the development of raw material. Therefore, it is needed a method to produce a high quality and quantity of paper. Acacia is one of paper raw material. To increase the growth of acacia seed, an effective usage of Rhizobium and Phosphate Solubilizing Microbe (pSM) seedling inoculant is one of strategies to produce good acacia seeds. The Rhizobium and Phosphate Solubilizing Microbe seedling inoculant can reduce anorganic fertilizer usage and increase the growth of acacia seed. The aims of this research were to select Rhizobium which has an ability to fix atmosphere N2 air and local Phosphate Solubilizing Microbe in dissolving phosphate, also to test the ability of those isolates in increasing the growth of acacia seedling. This research was conducted in the Soil Biotechnology Laboratory, Department of Soil and Land Resource Science, Faculty of Agriculture, Bogor Agricultural University and RAPP greenhouse (Pelalawan and Pangkalan Kerinci R&D Nursary) in Riau. Plant media is cocopit. The experiment consisted of 15 Rhizobium treatments isolated from peat soil, which was planted with A. crassicarpa, and mineral soil, which was planted with A. mangium; 16 Phosphate Solubilizing Microbe treatments taken from peat and mineral soil with 5 replications . The research resulted 2 Rhizobium isolates from IS tested isolates, which could increase the growth of A. crassicarpa effectively, those were Rh Ac S and POS-RIS, and 2 Phosphate Solubilizing Microbe from 16 tested isolates, those were BPF 4 and FPF S. While on A. mangium, there were 2 isolated out of 15 Rhizobium isolates which could increase the A. mangium growth effectively, those were M32-M33-R2N and M45-R2N; also 3 isolates out of 16 Phosphate Solubilizing Microbe, those were M32-BP3, FRK2, and M33-FP2. The characteristic of effectiveness could be seen from the plant height, the amount of leaves, the dry root wight, the dry plant weight, the diameter of bar and the root compactness; so that the usage of Rhizobium inokulan, Rh Ac 5 and P05-RIS equal to the usage of 0.1 kgll Monopotassiumphosphate fertilizer and better than control. Meanwhile the usage of MPF, BPF 4 and FPFS equal to the usage ofO.SI1 kg of Osmocote fertilizer and better than control.
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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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