Judul: Evaluasi perbaikan kualitas estetik lanskap pemukiman kumuh di Kota Bogor dengan simulasi komputer
Abstrak: Jak Nitrogen is one of the important soil nutrients needed in a large number. The released N from organic matter cannot be used directly by plant, it has to be mineralized and changed into available forms (N-NH4+ and N-NO3) for the plants. Nitrate is disappeared easily from the soil through denitrification, leaching and plant absorption. The objective of this research is to notify the availability of nitrogen in rice straw and compost of rice straw amanded to flooded soil as a result of N mineralization and its effect on soil pH. The experiment was done in the Laboratory of Soil Chemistry and Fertility and Laboratory of Soil Biology, Department of Soil Sciences, Faculty of Agriculture, Bogor Agricultural University. The organic materials used in this experiment were rice straw (B₁), compost of rice straw 4 month (B2) and compost of rice straw 8 month (B3). Organic materials were applied at a uniform rate of 92 kg N ha¹. Organic materials were mixed with 1,000 g soil (oven 105 °C-dry basis) and then added aquades. The soil was plowed under flooded condition and the mixture was incubated for 120 days. Nitrogen mineral of N-NH4 and N-NO3 and soil pH were analyzed at 0, 7, 14, 21, 47, 70, 96 and 120 days. The results showed that the form dominant N-mineral in the flooded soil is in the form of N-NH₄⁺. The availability of N-NH, from rice straw in flooded soil after 21 days of incubation period is much higher and faster than that of N-NH4 from compost of rice straw (4 month and 8 month composting). The concentration of N-NO; however in soil, sharply decreased in the initial of incubation period after flooding the soil. It might be due to the reduction of N-NO; in soil by immobilization and denitrification process. The addition of rice straw in the flooded soil increased soil pH higher than soil pH before a treatment...
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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: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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