Judul: Pengaruh Pemupukan Anorganik (N, P, K) dan Potensi Limbah Sereh Wangi sebagai Bahan Organik terhadap Pertumbuhan dan Produksi Jahe Gajah (Zingiber officinale Rosc.).
Abstrak: Exports of ginger from Indonesia in the last three years has declined because the quality of the ginger can not meet world market competitiveness. Suboptim cultivation techniques become a constraint in the development of the ginger plant coupled with the excessive use of synthetic chemical fertilizers that causes low soil capacity. The development of environmentally friendly technology to reduce the use of synthetic chemical fertilizers is expected to address the development problems of the ginger plant. Cultivation systems based on the utilization of in-situ organic materials such as waste of lemongrass (cymbopogon citratus) is widely available in the surrounding area of the ginger plant need attention so that the empowerment of local input and medicinal needs can be realize. The research aims to determine the effect of some several of organic materials and inorganic fertilizers (N, P, K) on the growth and production of young ginger, and weed growth. The research conducted at Bogor Agricultural University, Experimental Station, Cikabayan, Darmaga, Bogor, started September 2011 to April 2012 and used a split-plot design. The main plot consisted of organic materials consisting of granules (20 ton / ha), Cymbopogon citratus compost buried in soil (20 t / ha), Cymbopogon citratus compost mulch (20 t / ha) and without organic fertilizer as controls. Sub plot are inorganic fertilizer consisted of ½ doses (N, P, K), 1 doses (N, P, K), 2 doses (N, P, K) and without inorganic fertilizer. Organic materials and inorganic fertilizer did not significantly affect the growth component of ginger. Plants treated with ½ doses of inorganic fertilizer showed the highest dry weight of rhizomes and significantly different with 2 doses and plant resistance to disease is 54,98%. Combined treatment of lemongrass compost buried in soil and inorganic fertilizer showed the higest dry weight of total weeds, but combined treatment of lemongrass compost mulch and inorganic fertilizer showed the lowest dry weight of total weeds. Lemongrass can be used as the source of organic fertilizer and herbicid, depending on the method used and treatment.
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Judul: Study of the Effectiveness of Boron Application in Peat Soil on Ginger Growth and Production
Abstrak: Kebakaran hutan dan lahan sering terjadi di Indonesia. Salah satu komitmen mitigasi bencana kebakaran lahan gambut adalah kolaborasi perusahaan dengan masyarakat melalui pengelolaan area greenbelt. Salah satu tanaman yang mempunyai potensi ekonomi yang baik dan berpeluang untuk dikembangkan pada greenbelt adalah jahe. Kondisi lahan gambut yang miskin unsur hara, khususnya unsur mikro, menjadi tantangan dalam budidaya jahe. Penelitian ini menguji pengaruh boron terhadap pertumbuhan jahe di tanah gambut. Percobaan menggunakan rancangan acak lengkap (RAL) faktor tunggal yang dilakukan dengan pemberian B pada lima taraf konsentrasi (0, 0.4, 0.6, 0.8, dan 1 ppm). Respon tanaman dilihat dari beberapa parameter seperti tinggi tanaman, jumlah dan total daun, jumlah anakan, bobot basah dan kering tanaman serta bobot rimpang. Pemberian B sebesar 0.4 ppm pada tanah gambut berpengaruh nyata terhadap pertumbuhan tinggi batang jahe. Pemberian B sebesar 0.4-0.6 ppm berpotensi meingkatkan hasil produksi rimpang, bobot basah dan bobot kering tanaman., Forests and land fires often occur in Indonesia. One commitment to mitigating peatland fire disasters is the collaboration of companies with the community through greenbelt-area management. One plant with good economic potential that can be developed in the greenbelt is ginger. However, the poor nutrient conditions in peatlands, especially microelements, present a challenge for ginger cultivation. Therefore, this study aimed to test the effect of boron on the growth of ginger in peat soil. The researcher used a single-factor completely randomized design (CRD) to administer B at five concentration levels (0, 0.4, 0.6, 0.8, and 1 ppm) to assess plant response. Plant height, number and total of leaves, number of tillers, wet and dry plant weights, and rhizome weight, were used to measure plant responses. Providing B at 0.4 ppm in peat soil was proven to be effective in increasing the height of ginger stems. Providing B at 0.4-0.6 ppm has the potential to increase rhizome production, wet weight and dry weight of plant.
Keyword: Fertilization, Nutrient imbalance, Soil nutrient

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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