Judul: Potensi Salvinia molesta sebagai bahan kompos dan pengaruhnya terhadap perubahan sifat fisik tanah podsolik merah kuning gajrug serta pertumbuhan tanaman jagung (Zea mays L.)
Abstrak: Pertumbuhan populasi gulma air pada ekosistem perairan dalam kondisi yang tidak terkendali dapat mempengaruhi kondisi badan-badan air dan menurunkan kualitas air. Hal ini disebabkan karena gulma air dapat mempercepat proses pengendapan lumpur, sehingga menyebabkan pendangkalan badan air, menghalangi kelancaran aliran air, menghambat proses difusi oksigen di dalam badan air, mengurangi kapasitas biogenik perairan dan menghambat kegiatan perikanan. Gulma air Salvinia molesta termasuk jenis gulma air yang paling sulit dikendalikan pertumbuhannya, namun mempunyai manfaat sebagai makanan ikan, habitat untuk ikan bertelur, mengandung unsur hara yang dibutuhkan untuk mendukung perturnbuhan tanaman, dan pertumbuhannya relatif cepat sehingga mempunyai potensi sebagai surnber bahan organik. Dengan potensi tersebut maka upaya pengendalian populasi gulma air Salvinia molesta dapat dilakukan dengan memanfaatkannya sebagai sumber bahan kompos. Kompos sebagai bahan organik perlu dikembalikan ke dalam tanah untuk mendukung sifat fisik, kimia dan biologi serta menciptakan kesuburan alami pada tanah dan dapat mendukung pertanian organik dalam upaya meningkatkan produksi pertanian. Penelitian ini bertujuan untuk memperoleh infonnasi yang lebih banyak tentang potensi Salvinia molesta sebagai bahan organik dalam bentuk kompos, melihat pengaruh pemberian kompos tersebut terhadap sifat fisik tanah Podsolik Merah Kuning Gajrug dan pertumbuhan tanaman Jagung (Zea mays. L). Penelitian ini dilaksanakan di rumah kaca Jurusan Tanah, Faperta !PB, mulai bulan November I 996 sampai Agustus 1997. Analisis sifat fisik tanah dilakukan di Laboratorium Fisika dan Konservasi Jurusan Tanah, Faperta IPB.
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Judul: Kemungkinan Pemanfaatan Salvinia molesta D.S Mitchell dan Azolla pinnata R. Br. sebagai Penekan Gulma Padi Sawah
Abstrak: Berdasarkan pengamatan dan penguharan terhadap parameter-parameter di atas ternyata penutupan cover crop dan penyiangan berpengaruh sangat nyata terhadap penekanan pertumbuhan gulma golongan berdaun lebar, golongan rumput dan gulma secara keselurmhan. Dua spesies gulme. gang nyata tertekan pertumbuhannya adalah Echinochloa crusiralli dan Konochoria varrinalis. Spsies lsinnya umumnya cenderung tertekan, tetapi pengaruh perlakuan secara statistik tidak nyata.
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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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