Judul: Pemanfaatan Fe3+ dalam meningkatkan kelarutan Cu pada tanah gambut dari Kalimantan Tengah
Abstrak: Pemanfaatan tanah gambut di Indonesia untuk pertanian dihadapkan pada kendala produktivitas tanah yang tergolong rendah. Di antara penyebab rendahnya produktivitas tanah gambut adalah rendahnya kadar unsur-unsur hara, termasuk hara Cu. Fenomena ini diantaranya disebabkan oleh tingginya kandungan asam-asam organik, khusunya asam-asam fenolat yang memebentuk komplek kelat. Penelitian ini bertujuan untuk mempelajari pengaruh pemberian Fe3+ terhadap kelarutan Cu pada tanah gambut.
Keyword: 

Judul: Peningkatan kelarutan Cu melalui penambahan Fe (HI) dan Cu pada gambut pantai dari Handil Sohor, Kalimantan Tengah
Abstrak: Pengaruh toksisitas asam-asam organik dan rendahnya kandungan unsur hara khususnya unsur Cu merupakan kendala dalam pengembangan lahan gambut untuk pertanian. Penelitian ini bertujuan untuk: (1) mempelajari pengaruh pemberian Fe(III) dan Cu terhadap kelarutan Cu pada gambut pantai dari Handil Sohor clengan tingkat dekornposisi fibrik, hemik, dan saprik dan (2) mengetahui distribusi bentuk kation Fe(III) clan Cu clalam garnbut. Penelitian ini dilaksanakan mulai dari bulan April 1997 hingga September 1997. Dalam pelaksanaannya, penelitian dilakukan di empat laboratorium, yaitu: Laboratoriurn Kimia Tanah, Jurusan Tanah, Fakultas Pertanian, IPB; Laboratorium Terpadu Analisis Kimia, IPB; Laboratorium Biokimia, Balittan, Cimanggu, Bogor; dan Laboratorium FMIPA, UNILA, Lampung. Basil penelitian menunjukkan bahwa penambahan Fe(III) clan Cu berpengaruh nyata terhadap penurunan pH tanah. Penurunan pH terbesar clihasilkan setelah pcmberian 200 ppm Cu dan 5% erapan maksimum Fe (perlakuan C1F2 ) dengan nilai pH= 3.35.
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: