Judul: Studi Aplikasi Herbisida Pra Tumbuh pada Dua Jrak Tanam Jahe (Zingiber officinale Rosc.) Jenis Badak
Abstrak: Percobaan ini bertujuan untuk mengetahui keefektifan penggunaan herbisida pra tumbuh metolakhor, metolakhor + metobromuron, metolakhor + prometrin, dan pengendalian secara manual yang keduanya dikombinasikan dengan pengaturan dua jarak tanam 60 cm x 40 cm dan 80 cm x 30 cm.
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Judul: Studi aplikasi pembenah tanah dan herbisida terhadap pertumbuhan dan produksi jahe badak pada lahan bekas alang-alang
Abstrak: Penelitian ini bertujuan untuk mengetahui pengaruh pengendalian gulma dan pembenah tanah terhadap pertumbuhan dan produksi jahe jenis Badak yang dipanen muda (5 bulan) pada lahan bekas alang-alang. Hipotesis yang diajukan ya- itu (1) Pembenah tanah mempengaruhi pertumbuhan, perkembangan dan peningkatan hasil jahe, (2) Herbisida pra tumbuh mampu menekan pertumbuhan gulma dan membantu mening- katkan hasil jahe dan (3) Terdapat interaksi antara pembe- nah tanah dengan herbisida pra tumbuh terhadap pertumbuh- an, perkembangan serta hasil rimpang jahe. Penelitian ini dilaksanakan di Cikasungka, Bogor. Percobaan berlangsung mulai bulan November 1992 sampai de- ngan bulan Maret 1993. Bahan yang digunakan berupa bibit jahe jenis Badak, sekam padi, pupuk kandang, Urea, TSP, KCl, herbisida ametryn, agrymicin dan pembenah tanah EB.a. Percobaan menggunakan Rancangan Acak Kelompok dengan 4 ulangan disusun secara faktorial terdiri atas dua faktor. Faktor pertama yaitu pembenah tanah EB.a yang terdiri atas empat taraf yaitu tanpa pembenah tanah EB.a sebagai kontrol (So), pembenah tanah EB.a dengan dosis 3.5 l/ha (S₁), pembenah tanah EB.a dengan dosis 7.0 1/ha (S2) (53). dan pembenah tanah dengan dosis 10.5 1/ha Faktor kedua yaitu faktor pengendalian gulma yang terdiri dari dua taraf yaitu tanpa herbisida atau siang manual 10 hari sekali (Go) dan dengan herbisida ametryn dosis 3.0 1/ha (G₁). Pengamatan dilakukan terhadap 10 tanaman contoh dan mencabut (destruksi) 2 rumpun tanaman jahe. Secara umum hasil yang ditunjukkan oleh perlakuan pembenah tanah EB.a berpengaruh nyata terhadap pertumbuhan dan hasil rimpang jahe, kecuali untuk peubah jumlah daun dan jumlah anakan. Perlakuan pengendalian gulma Go dan G₁ tidak menunjukkan pengaruh yang nyata pada semua peubah yang diamati. Terdapat interaksi yang positip antara per- lakuan pembenah tanah EB.a dan pengendalian gulma pada peubah tinggi tanaman dan bobot rimpang segar saat panen….
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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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