Judul: Penyemaian Benih Padi untuk Penanaman Menggunakan Metode Tanam Parasut.
Abstrak: Penanaman dengan metode parasut memerlukan komposisi media tanam yang cukup untuk memenuhi unsur hara dan ketahanan dalam menembus lumpur. Tujuan penelitian ini adalah merancang alat penebar gabah ke dalam tray, menentukan komposisi media tanam terbaik untuk bibit padi, dan mencari indeks kelunakan tanah yang cocok untuk penanaman dengan metode tanam parasut. Alat penebar gabah dalam penelitian ini di desain berbentuk miring dalam proses pemasukan gabah ke lubang tray dengan jumlah benih 3 sampai 5 gabah per lubang. Sudut lubang penjatah gabah yaitu 20°, dan setiap lubang memiliki ukuran diameter 1.5 cm, ketebalannya 0.6 cm, dan sudut kemiringannya 20°. Hasil uji kinerja alat penebar gabah menunjukkan nilai 38.45% untuk masuknya jumlah gabah yang sesuai dan 61.55% untuk masuknya jumlah gabah tidak sesuai. Interaksi masuknya bibit padi ke lumpur menunjukkan bahwa media tanam dengan komposisi 45% tanah (kg/kg) + 45% kompos kandang (kg/kg) + 10% arang sekam (kg/kg) merupakan media tanam terbaik. Indeks kelunakan dengan bola golf berada pada posisi 1 cm di bawah permukaan lumpur merupakan indeks kelunakan terbaik yang membuat bibit padi masuk ke dalam lumpur sedalam 2.8 cm.
Keyword: alat penebar gabah, indeks kelunakan (IK), media tanam, metode tanam parasut

Judul: Seeding and Dropping of Rice Seedlings in Order to Get the Proper Planting Depth and Seedling Position for Parachute Transplanting Method
Abstrak: Metode tanam parasut merupakan metode penanaman padi dengan cara menjatuhkan bibit padi yang berbentuk seperti parasut pada lahan. Pada metode ini, benih padi disemai pada tray khusus untuk membentuk beberapa rumpun bibit, di mana setiap rumpun berisikan media tanah sebagai pemberat dan bibit sebagai parasut. Penelitian ini bertujuan untuk menentukan ukuran media tanah dan ketinggian penjatuhan bibit dengan penanaman metode tanam parasut untuk mendapatkan kedalaman tanam dan posisi bibit yang sesuai. Bibit padi berumur tujuh hari setelah semai merupakan umur bibit yang paling baik. Hasil penelitian menunjukan perlakuan tanah lunak dengan nilai IK sebesar 90% menghasilkan kedalaman tanam rata-rata terbaik sebesar 12,5 mm. Bibit padi yang dijatuhkan dari ketinggian 500 cm menghasilkan kedalaman tanam rata-rata tertinggi sebesar 14,18 mm sehingga sesuai untuk diterapkan pada semua ukuran media tanah. Sementara itu, bibit dengan ukuran media tanah 6 mm x 6 mm x 15 mm merupakan bibit parasut yang ideal untuk dijatuhkan karena menghasilkan kedalaman tanam sebesar 11,9 mm yang sesuai dengan rentang kedalaman yang disarankan pada metode SRI., The parachute transplanting method is a seedling broadcasting technology by dropping parachute seedlings to the puddled soil. In this method, rice seeds are sown in trays to form seedling clumps, where each clump contains soil media as the ballast and seedlings as the parachute. This study aims at determining the size of soil media and the dropping height to obtain the appropriate planting depth and seedling position. The seedling age of seven days after sowing was found to be the best seedling age to drop. The results showed that soft mud with an IK value of 90% resulted in the best average planting depth of 12,5 mm. Parachute seedlings dropped from a height of 500 cm resulted in the highest average planting depth of 14,18 mm, making them suitable for application on all soil media sizes. Meanwhile, the 6 mm x 6 mm x 15 mm sized soil media is the ideal parachute seedlings to drop because give average planting depth of 11,9 mm, which is within the depth range suggested in the SRI method.
Keyword: parachute planting method, planting depth, seedling position, soil hardness, tray

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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