Judul: Efektifitas herbisida pra tumbuh dan mulsa terhadap penekanan gulma pada pembibitan panili (Vanilla planifolia Andrews Rosc.)
Abstrak: Percobaan ini bertujuan untuk mengetahui pengaruh beberapa herbisida pra tumbuh dan atau mulsa terhadap per- tumbuhan gulma dan stek panili. Percobaan ini disusun dalam rancangan petak terbagi. Sebagai petak utama adalah jenis mulsa yang terdiri 3 jenis yaitu tanpa mulsa (MO), sekam (M1) dan jerami (M2). Sedangkan sebagai anak petak adalah jenis herbisida pra tumbuh yang terdiri 4 jenis yaitu tanpa herbisida (HO), Ametryne (H1), Diuron (H2) dan Oxyfluorfen (H3). Dalam percobaan ini diperoleh 12 kombinasi perlakuan dan diulang 6 kali sehingga terdapat 72 satuan percobaan. Hasil percobaan menunjukkan adanya pergeseran jenis dan komposisi gulma daun lebar dan rumput akibat campuran pupuk kandang dan atau oleh perlakuan mulsa dan herbisida. Perlakuan mulsa, herbisida dan interaksinya berpengaruh nyata dalam menurunkan jumlah gulma daun lebar dan rumput. Bobot kering gulma daun lebar dipengaruhi oleh perlakuan herbisida atau mulsa sedangkan bobot kering gulma rumput hanya dipengaruhi oleh perlakuan herbisida. Jumlah gulma maupun bobot kering gulma tidak berbeda. secara nyata antar ketiga jenis herbisida dan kedua jenis mulsa yang diaplikasikan.
Keyword: 

Judul: Studi aplikasi mulsa sekam padi, periode pembumbunan dan herbisida pratumbuh terhadap penekanan gulma pada pertanaman jahe varietas badak (Zingiber officinale Rosc.)
Abstrak: Hasil percobaan menunjukkan perlakuan mulsa sekam padi cenderung meningkatkan jumlah daun, jumlah anakan, bobot kering akar, bobot kering daun, bobot kering rim- pang, bobot brangkasan, bobot segar rimpang, produksi rimpang/ha serta dapat menghambat pertumbuhan gulma di- banding tanpa mulsa sekam padi. Perlakuan herbisida pratumbuh dapat menekan bobot kering total gulma, bobot kering tiga gulma dominan (Ageratum conyzoides, Borreria alata dan Commelina benghalaensis) dan gulma lain serta persentase penutupan gulma. Interaksi perlakuan mulsa dan herbisida dapat menekan persentase penutupan gulma. Perlakuan pembumbunan tidak menunjukkan pengaruhnya pada semua peubah yang diamati. Interaksi ketiga faktor tidak menunjukkan pengaruh yang nyata pada semua peubah yang diamati. Secara umum hasil yang ditunjukkan oleh perla- kuan mulsa terhadap pertumbuhan dan produksi rimpang jahe berturut-turut mulsa dengan dosis 40 ton/ha....
Keyword: 

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.
Keyword: