Judul: Nitrogen transformation in flooded soil: application of rice straw and urea and its relation with nitrogen uptake and rice plant growth
Abstrak: The use of organic materials aimed at reducing the dependence on inputs such as chemical fertilizers can contribute to sustainability and improving the low N fertilizer efficiency of rice plants in paddy soils. Therefore, better understanding of N transformation in flooded soils, particularly the microbial transformation of N-organic amendments to plant-available N and gaseous N forms is needed: (1) for most efficient use of soil and organic materials N by rice plant , (2) for determining the potential of denitrification and (3) for aiding in the selection of N management practices for sustainable agriculture.
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Judul: Efisiensi Penggunaan Nitrogen Pada Padi (Oryza sativa L.)
Abstrak: Nitrogen fertilizer in the form of urea has become a staple for farmers, especially in Indonesia. Consequently, applying such large quantities of urea cannot be avoided. The understanding of nutrient-use efficiency on paddy-field is needed to increase plant productivity and reduce environmental pollution because of the utilization of luxury urea fertilizer. The objective of this research was to quantify the nitrogen-use efficiency (NUE) on paddy-field. This study was conducted in field and green house. The experiments were carried out in the experimental field at the Indonesian Center For Rice Research (ICRR), Subang-West Java and farmer’s field at Bogor– West Java. The N fertilizer applied in ICRR and farmer field were 225 and 612.25 kg urea/ha, established in experimental plots of about 25 m2. The N fertilizer applied in the green house experiment were 200, 300, 400, 500 and 600 kg urea/ha, respectivelly. The result showed that the NUE and N resorption were higher in ICRR than that of in farmer’s field. The green house experiment showed that the NUE and N resorption were higher under 500 kg urea/ha than other treatments. The plant growth, plant biomass, grain yield, NUET, NUEES, ANUE, PNUE dan N resorption were declined with the high availability in nitrogen-pool and increasing in large quantities at certain doses of N fertilizer.
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Judul: Berat Badan Dan Morfometrik Leopard Gecko (Eublepharis Macularius) Pada Berbagai Umur
Abstrak: Leopard gecko (Eublepharis macularius) adalah jenis tokek yang hidup di permukaan tanah dan aktif saat fajar dan senja. Studi morfometrik dalam leopard gecko masih terbatas. Tujuan dari penelitian ini adalah untuk mengukur dan membandingkan berat badan dan morfometrik leopard gecko dari berbagai umur. Sebanyak 14 ekor leopard gecko (3 ekor jantan dan 11 ekor betina) dikelompokkan menjadi empat kelompok: 0-6 bulan, 7-12 bulan, 13-18 bulan, dan 19-24 bulan. Pengukuran dilakukan setiap bulan selama tiga bulan sehingga hewan dapat ditimbang dan diukur lebih dari sekali. Selama 90 hari pascatetas, pengukuran berat dan panjang dilakukan setiap hari, dua hari, atau setiap minggu tergantung dengan tingkat pertumbuhan. Hasil penelitian menunjukkan bahwa kelompok umur 0-6 bulan memiliki berat badan 10.69±5.68 g dan total panjang 12.79±3.68 cm; 7-12 bulan memiliki berat badan 16.57±4.52 g dan total panjang 16.7±1.23 cm; 13-18 bulan memiliki berat badan 21.12±3.13 g dan total panjang 19.4±1.15 cm; dan 19-24 bulan memiliki berat badan 27.9±1.53 g dan total panjang 20.8±1.51 cm. Dapat disimpulkan pada leopard gecko kelompok umur 0- 6 bulan memiliki pertumbuhan yang lebih bervariasi pada berat badan, panjang kepala, panjang kaki belakang, dan panjang ekor dibandingkan dengan yang lain.
Keyword: berat badan, Eublepharis macularius, morfometrik, tokek