Judul: Perbandingan Respons Tanaman Sorghum Terhadap Pemberian Kombinasi Kalsit-Guano Fosfat Dan Terak Baja-Guano Fosfat Pada Tanah Podsollk Merah Kuning Dari Jasinga
Abstrak: Penelilian ini bertujuan untuk membandingkan pengaruh kombinasi kalsitguano fosfat dan kombinasi terak baja-guano fosfat terhadap ketersediaan P, pertumbuhan, dan serapan P tanaman sorghwn pada Podsolik Merah Kuning dari Jasinga.
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Judul: Perbandingan Respons Tanaman Sorghum Terhadap Kombinasi Terak Baja-Guano Fosfat Dan Kombinasi Terak Baja-sp 36 Pada Podsolik Merah Kuning (Typic Hapludults) Dari Jasinga
Abstrak: Pennasalah utama tanah-tanah di Indonesia adalah tingk.at kemasamannya yang tinggi. Tingkat kemasaman yang tinggi ini menyebabkan rendahnya tingkat efisiensi pemupukan salah satunya rendahnya efisiensi pemupukan P. Untuk mengatasi hal tersebut diperlukan pengapuran dan jenis pupuk P yang tepat dan murah, salah satu kapur dan pupuk P altematif adalah terak baja dan guano fosfat. Penelitian ini bertujuan untuk rnengevaluasi relatif agronomic effectiveness (RAE) guano fosfat dengan SP 36 sebagai pupuk pernbanding pada tanaman sorghum dan menentukan dosis kombinasi terak baja-guano fosfat yang menghasilk.an produksi bobot kering tanaman sorghum tertinggi. Pemelitian ini dilaksanakan di rumah kaca Jurusan Tanah, IPB. Analisis tanah dan tanaman dilaksanakan di Laboratorium Kimia clan Kesuburan Tanah, Jurusan Tanah, IPB. Penelitian ini dilaksanakan dari bulan Desember 2000 sampai dengan bulan Desember 2001. Perlakuan yang diberikan berupa kombinasi 3 taraf terak baja (0 x Aldd, 1 x Aldd, dan 2 x Aldd) dengan 4 taraf guano fosfat atau 4 taraf Sp 36 (0, 100,200,300 ppm P20s). Hasil penelitian menunjukan bahwa pemberian kombinasi terak baja-guano . fosfat dan terak baja-SP 36 nyata meningkatk.an tinggi, bobot kering, dan serapan P tanaman. Hal tersebut diduga dikarenakan adanya penambahan P dari kombinasi tersebut. Bobot kering tanaman tertinggi dicapai pada perlakuan S2P3, yaitu sebesar 33.85 g/pot. Nilai RAE yang dihitung berdasarkan bobot kering dan serapan P tanaman menunjukan bahwa semakin tinggi dosis terak. baja maka nilai RAE-nya semakin rendah. Nilai RAE tertinggi berdasarkan bobot kering dan serapan P tanaman dicapai pada perlakuan S0O3, yaitu masing-masing sebesar 1533 % dan 217 %. Dari hasil analisis tanah yang dilakukan dapat diketahui bahwa pemberian kombinasi terak baja-guano fosfat dan kombinasi terak baja-SP 36 nyata meningkatkan pH tanah, P tersedia, Ca-dd, Mg-dd, nyata menurunkan Al-dd, tetapi tidak berpengaruh nyata terhadap K-dd.
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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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