Judul: The study of controlling iron toxicity on rice in the tidal swamp land through the diversity of rice genotypes and land amelioration
Abstrak: The experiments were conducted in the greenhouse of Bogor Agriculture University, from May to November 2010, and field experiment in the tidal swamp area, Barito Kuala regency, South Kalimantan, from February to November 2011. The objectives of the experiment were 1) to obtain the Fe concentration in the solution that causing iron toxicity symptom with criteria severe, moderate and slightly, 2) to obtain tolerant or rather tolerant (moderate) rice genotypes to Fe toxicity, 3) to study the mechanism of tolerance of rice genotypes to Fe toxicity, 4) to obtain the adaptive Salvinia sp. which have high biomass 5) to study the effect of rice genotypes, land amelioration and its combination to iron toxicity at two location and two cropping season in the tidal swamp land. Result of the first experiment which were conducted in the green house showed that after 4 weeks, iron toxicity symptoms of IR 64 variety can be grouped based on Fe concentration, i.e. slightly (skoring 3) = 52 ppm Fe, moderate (scoring = 5) = 143 ppm Fe and severe (scoring 9) is 325 ppm Fe. Iron toxicity symptoms of four genotypes (TOX4136, Inpara-1, Inpara-2, and Inpara-4) which have been selected at 325 ppm Fe concentration were lower in the field experiment. Inpara-1 and Inpara-4 genotypes more tolerant to Fe toxicity than other genotypes and had higher productivity at two experimental sites. The tolerant genotype retain more Fe on surface roots (plaque Fe) and had a ratio of Fe stems/leaves higher than the sensitive genotype. The ability of tolerant genotypes retain more Fe on the root surface (Fe plaque) indicated the existence of mechanisms of avoidance to iron toxicity in rice. Results of 10 Salvinia sp. accessions eveluation in nutrient solution with 7 ppm Fe concentration obtained 4 Salvinia sp. accessions had faster growth with doubling time of 6.0-8.6 days. Countinous testing of four accession of Salvinia sp. at soil of tidal swamp in a pot obtained one accession of Salvinia sp. from S. Kambat had growth and doubling time faster than other accession. Salvinia sp. accession from S. Kambat grown in the field showed growth and doubling time faster (5.1 days and 5.9 days) than which in the greenhouse at 7 ppm Fe in nutrient solution (7.5 days) and the soil of tidal swamp land in a pot (7.9 days). Land amelioration and tolerant genotypes can be control iron toxicity on rice and increased rice productivity in the tidal swamp area. Salvinia sp. which grown or composted had no different with composted rice straw and farmyard manure. The Belandean site had higher iron toxicity level and lower rice productivity than the Danda Jaya site. Iron toxicity can reduce grain yield in tidal swamp land 15.6-63.9% (scoring 2-7) compared to plant which grow normally (scoring 1). Level of iron toxicity at second cropping season lower than at first cropping season.
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Judul: Efficiency of fertilizer with enriched straw compost under system of rice intensification (SRI)rice cultivation in tidal areas of South Kalimantan.
Abstrak: System of Rice Intensification (SRI) is a rice cultivation by which can be done in tidal rice fields. The application of this method must be supported by efforts to address the major issues in tidal land, mainly low soil fertility status and high solubility of the elements namely Fe, Al and Mn whichcaused toxic to plants. Composted rice straw is an alternative ameliorantcan be used to resolve the tidal land problems, howevercomposting process naturally takes 2-3 months. Aplication of microbial cellulolytic making shorten decomposition by rice straws become possible. Free living N2 fixing bacterium such as Azotobacter would able to increase N-available to the plant turn higher N uptake of the plant.The main objective of this study was to isolate the cellulolytic microbial from tidal rice fields that could accelerate straw decomposition and study the effect of enriched compost on nutrient uptake efficiency of N, P and K and rice yield,and study the potential toxicity of Fe, Al and Mn under SRI compared to conventional rice cultivationson in a tidal rice field of South Kalimantan.This study is consisted of two experiments. It was collected 100 samples natural rice straw compost from 16 sites in the tidal rice fields in South Kalimantan from first experiment. 143 cellulolytic isolates have been isolated from the samples. Collectred isolates were then tested ability to excrete cellulase, resistance to soil pH changes and acceleration to the straw decomposition.A completely randomized block design with two factors was used in the field trial. The main plot were SRI and convensional rice cultivations, and as subplots were eight fertilizerstreatments that were a combination between Azotobacter enriched compost with inorganic fertilizersdosages. The results showed that four isolates of microbial cellulolytic namely bacteria GA22 and ST22, and fungi SN123 and C52 were found as a superior strains to excrete cellulaseenzyme, resistance to changes in soil pH and could accelerate composting processes. Although all cellulolytic isolates collected from acid soil,most of them had ability to grow better in neutral pH.The enriched compost could reduce the use of fertilizer N, P and K as much as 25% fertilizer of recommended dosage.The enriched compost with dosage 75% of N, P and K fertilizer could increase N, P and K uptake efficiencies. SRI could be applied in type B of tidal rice fields during dry season,and implementation of SRI was able reduce the potential of Fe toxicity. Ultimately,Ciherang variety of rice yielded 4.34 tons/ha if cultivated under SRI, whereas under the conventional rice cultivation was 3.56 tons/ha
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Judul: Formulasi Algoritme Operasi Grup Jacobian Kurva Hyperelliptic ...
Abstrak: Dalam geometri aljabar, kurva hyperelliptic merupakan bentuk umum dari kurva elliptic. Kurva ini apabila dikenakan pada suatu lapangan berhingga akan membentuk suatu grup siklik. Pada kriptografi, khususnya enkripsi kunci publik, grup siklik yang dibangkitkan oleh kurva elliptic sudah banyak diteliti. Bahkan untuk kurva ini sudah memiliki standar oleh National Institute of Standard and Technology (NIST) Amerika. Sedangkan, untuk grup yang dibangkitkan oleh kurva hyperelliptic masih memiliki kekurangan dalam hal komputasinya. Tujuan dari penelitian ini adalah mengkonstruksi suatu lapangan berhingga pada , memilih kurva hyperelliptic atas lapangan hingga yang memenuhi kriteria keamanan untuk kriptografi, dan membuat formulasi operasi grup kurva hyperelliptic menggunakan algoritme Cantor. Dalam merekonstruksi lapangan hingga, terlebih dahulu tentukan dimensi dari lapangan hingga tersebut dan polinomial tak-teruraikan. Kemudian dipilih kurva hyperelliptic atas lapangan tersebut. Pada penelitian ini, kurva yang dipilih adalah = + + dengan lapangan hingga . Berdasarkan kurva yang dipilih, akan dibentuk suatu operasi grup dengan menggunakan algoritme Cantor, sehingga menjadi lebih aritmatik. Eksplorasi kurva hiperelliptic dilakukan untuk mengetahui keamanan dari kurva yang dipilih. Dengan menyusun algoritme operasi grup dari kurva yang dipilih, diperoleh perhitungan yang lebih aritmatik dan dapat diimplementasikan pada kriptografi kunci publik. Dari segi keamanan kurva telah memenuhi standar sehingga tahan terhadap serangan-serangan seperti Poligh-Hellman, Polard- , ataupun Frey-Ruck secara teorema.
Keyword: algoritme Cantor, kriptografi, kunci publik, kurva hyperelliptic, operasi grup