Judul: Model Neraca Nitrogen pada Pertanian Indonesia serta Dampak yang Ditimbulkan Tahun 1968 dan 2008
Abstrak: Intensification has been choosen as a main effort of agricultural development in Indonesia. The measure of fertilizer is the main characteristic of intensification within which urea (nitrogen) is the most common fertilizer. This study was conducted to assess the efficiency of nitrogen and nitrogen Past to the environment, to estimate its environmental impacts and to find their mitigation measures of fertilizer application. In order to obtain a comprehensive result, system aproach was used. Secondary data and other sources of reliable information were used. Four inputs entering the system are mineral fertilizer, plant N-fixation, soil bacterial fixation and precipitation. Nitrogen mass-balance models were developed to determine production, efficiency and the nitrogen losses. The result showed the Same trend of the system, increased the the lost and decrease the efficiency around 1968 dan 2008. From the material balance model outputs, it is predicted that around 138 kg-N/ha-year are lost and antering the environment or ecosystem. It is estimated that the future Indonesian agriculture will be more intensive and fertilizer application will increase. Fertilizer impacts are decreasing of nitrogen efficiency, soil organic matters, macroelements and organisms, groundwater contamination and air pollution. To avoid most of the possible adverse effects, some efforts might be made by reduce the use mineral fertilizer, increasing legume, use of azolla and increase the use organic fertilizer (green and animal manure). A recommended that used the future Indonesian agricultural development to Sustain the agricultural production should be optimize input agricultural and minimizing losses.
Keyword: Nitrogen fertilizer, Model, Efficiency, N-loss, agricultureA

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.
Keyword: 

Judul: Phylogenetic analysis of subgenus Dieramalpinia (Alpinia carolinensis clade) - Zingiberaceae based on ITS sequences
Abstrak: The most recent infra-generic classification of Alpinia Roxb. by Smith divided the genus into two subgenera (Alpinia and Dieramalpinia) with 11 sections and 12 subsections. One of the sections of Alpinia subgenus Dieramalpinia is Myriocrater which contains about 16 species. The most recent phylogenetic study that included species from Alpinia subgenus Dieramalpinia was done by Kress et al. (2007). They sampled only eight species and found that these were nested within a clade referred to as the Alpinia carolinensis clade. This clade was well supported and may be separated as a genus if sampling more species confirms the result. The objectives of the present project are to compare ITS within one species; to test the monophyly of Alpinia section Myriocrater; to test whether adding more samples still supports the Alpinia carolinensis clade. The present study included thirty-nine samples representing nineteen taxa from Alpinia; seven samples are still unidentified at species level. Sequences of the Internal Transcribed Spacer were used in the analysis. The result showed that ITS sequence of Myriocrater’s species are more conserved than another group in Zingiberaceae. There are base variations within species level. The Alpinia section Myriocrater plus five species from other section is not monophyletic. The Alpinia carolinensis clade still includes three sections of Smith classification (Dieramalpinia, Myriocrater and Pycnanthus) from subgenus Dieramalpinia. Alpinia subgenus Dieramalpinia section Eubractea and one species of section Dieramalpinia are separated into another clade.
Keyword: Alpinia, Myriocrater, Dieramalpinia, Alpinia carolinensis clade