Judul: Aplikasi Volume Rendah dan PEnambahan "Additive" untuk Meningkatkan Efikasi Herbisida Pada Pengendalian Gulma di Jalur Tanaman Karet TBM
Abstrak: Percobaan pengendalian gulma yang bertujuan untuk memperoleh jenis alat semprot yang dapat menghemat pemakaian bahan pelarut, dosis herbisida, waktu dan tenaga telah dilakukan dengan menggunakan 4 jenis alat semprot, 2 jenis herbisida dan bahan aditive L-77. Aditive L-77 diharapkan dapat meningkatkan efikasi herbisida pada dosis rendah.
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Judul: Studi keefektivan aplikasi herbisida dengan aplikator volume rendah untuk pengendalian gulma pada jalur karet menghasilkan (TM)
Abstrak: Aplikator volume tinggi telah umum digunakan, dengan volume semprot 400 - 1000 1/ha. Volume yang tinggi tersebut akan menjadi masalah yang serius terutama jika digunakan pada daerah-daerah dimana air sulit diperoleh, pada daerah terpencil atau berbukit-bukit dan masalah yang dihadapi akan bertambah jika menggunakan herbisida tertentu yang menghendaki persyaratan kualitas air yang baik. Untuk mengatasi kesulitan tersebut, dikembangkan aplikator yang dapat menghemat pemakaian air tanpa mengurangi hasil pengendalian, selain itu aman dalam pemakaiannya. Salah satu dari alat tersebut adalah aplikator CDA tipe "Mikron Herbi 77". Penelitian ini bertujuan untuk mengetahui keefektivan aplikator volume rendah dan pengaruh beberapa jenis herbisida dalam mengendalikan gulma di jalur karet menghasilkan. Percobaan dilakukan di kebun Cimulang, PT Perkebunan XI Bogor, dari bulan Oktober 1987 sampai dengan bulan Januari 1988. Perlakuan disusun secara faktorial dalam acak kelompok. Faktor aplikator terdiri atas aplikator volume tinggi (semprot punggung) dan aplikator volume rendah (mikron herbi). Jenis herbisida terdiri atas Glyphosat 36 % w/v dosis 1,50 1/ha, 1,00 1/ha dan 0,75 1/ha, Para- qu at 25 % w/vdosis 2,00 1/ha, Glufosinat 25 % w/v dosis 2,00 1/ha dan Imaxapyr 33 % w/v dosis 1,00 1/ha. Penyemprotan dilakukan pada saat yang bersamaan langsung ke petak percobaan yang berukuran 20 mx 2m...
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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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