Judul: Uji daya gabung isolan-isolan Rhizobium japonicum pada berbagai varietas kedelai (Glycine max(L) merril)
Abstrak: Telah diketahui bahvra antara varietas kedelai dan galur Rhizobium Javonicum terdapat spesifisitas. Keberhasilan inckulasi sangat ditentukan oleh hubungan simbiosis antara galur Rhizobium Javonicum dengan varietas kedelai . Percobaan ini bertujuan untuk menguji daya gabung inokulant Rhizobium ria~onicum pada berbagai varietas kedelai dan melihat kekhvsusan pasangan antar keduanya.Percobaan disusun menurut Rancangan Petak Terpisah yang diulang tiga kali. Petak utama merupakan perlakuan lima galur hasil isolasi bintil akar efektif dan satu inokulant komersial Nitragin.
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Judul: Uji efektivitas lima isol dalam larutan terhadap tiga varitas kedelai
Abstrak: Suatu galur spesifik Rhizobium japonicum dapat membentuk bintil akar dan memfiksasi N pada beberapa varietas kedelai, sedangkan galur lain tidak dan sebaliknya. Percobaan bertujuan untuk menguji efektivitas lima isolan R. japonicum dalam larutan terhadap tiga varietas kedelai. Percobaan disusun menurut rancangan faktorial dalam acak lengkap dengan tiga ulangan. Varietas yang digunakan tidak mempunyai hubungan kerabat yaitu Americana, Galung- gung dan UFV-1. Lima isolan R. japonicum yang digunakan diisolasi dari bintil akar efektif ketiga varietas tersebut. Perlakuan yang tidak diinokulasi dengan maupun tanpa pupuk N serta inokulasi Nitragin (inokulan komersial) digunakan sebagai pembanding. Hasil percobaan menunjukkan bahwa hampir semua isolan R. japonicum yang diuji efektif dalam membentuk bintil akar pada varietas Americana, Galunggung dan UFV-1, kecuali isolan 1 pada varietas Galunggung. Dengan demikian hubungan antara galur R. japonicum dan varietas kedelai yang diuji tidak terlalu spesifik seperti yang diduga semula. Jumlah sumbangan N fiksasi oleh semua isolan lebih tinggi dari pembanding Nitragin tetapi lebih rendah di- banding pemupukan 135 kg N/ha. Diduga keadaan ini disebab- kan sesuatu faktor yang menghambat fiksasi N oleh isolan yang diuji. Varietas Americana mempunyai berat kering tajuk, berat kering akar, kandungan N tajuk, jumlah bintil akar dan berat 100 biji lebih tinggi dibandingkan dengan varietas Galunggung dan UFV-1.
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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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