Judul: Pengaruh beberapa senyawa nitrogen organik tanah pada aktifitas fiksasi nitrogen oleh Azoidbacter vinelandii pada media cair modifikasi burk
Abstrak: Penelitian ini bertujuan melihat pengaruh beberapa senyawa nitrogen organik tanah dilihat dari aspek biokimia /biologi terhadap aktifitas fiksasi nitrogen (fn) oleh A­ zotobacter vinelandii pada skala laboratorium. Penclitian dasar ini akan mengungkapkan beberapa aspek biokimia/bio­ logi fn oleh A. vinelandii secara nonsimbiose (mandiri) pada media cair modifikasi Burk sebagai media baku. Aspek biokimia yang akan dipelajari meliputi : gambaran laju per tumbuhan dengan mencoba selang waktu pengamatan setiap 3, 6, 12 dan 24 jam, ketergantungan aktifitas fn terhadap asam n trilotriasetat dan garam Mo. pengaruh 8 senyawa nit­ rogen organik tanah, urea serta nitrat pada media. Obyek pengamatan ialah tingkat aktifitas fn dengan menggunakan 4 parameter yaitu : gambar kurva laju pertumbuhan selama pengamatan, kekeruhan, bohot kering biomassa sel, populasi sel dan N-terfiksasi atau N-total biomassa sel pada saat akhir fase pertumbuhan eksponensial.
Keyword: Modifikasi Burk;, Azotobacter Vinelandi;, Soil Microbiology;

Judul: Pengaruh Inokulasi Azotobacter sp. terhadap ..Perakaran Jagung pada Beberapa Tingkat Pemberian KNO3 di Media Padat Watanabe
Abstrak: Pemupukan N merupakan salah satu upaya yang dilakukan untuk meningkatkan ketersediaan hara N yang diperlukan tanaman untuk pertumbuhan. Sumber nitrogen yang terdapat dalam tanah, tidak selalu mencukupi kebutuhan tanaman, sehingga perlu diberikan pupuk sintetik yang merupakan sumber nitrogen untuk mempertinggi produksi pertanian. Akan tetapi penggunaan pupuk sintetik yang berlebihan menimbulkan residu yang membahayakan lingkungan. Oleh karena itu diperlukan alternatif lain untuk mengatasinya, salah satunya adalah penggunaan pupuk hayati yang mengandung mikroba tanah. Salah satu mikroba tersebut adalah Azotobacter sp. Azotobacter sp. dikenal sebagai bakteri penambat N2 non simbiotik dan penghasil zat pengatur tumbuh. Inokulasi Azotobacter sp. mampu meningkatkan produksi dan memperbaiki pertumbuhan tanaman pangan. Penelitian ini dilakukan untuk mengetahui kemampuan beberapa isolat Azotobacter sp. dalam memperbaiki perakaran jagung pada beberapa tingkat pemberian hara N dalam bentuk KNO3 pada media padat Watanabe.
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Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite