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: Ambang Batas Fe dalam Pupuk Organik yang Berpotensi Menyebabkan Keracunan Fe Pada Tanaman Padi Sawah
Abstrak: Many scientists reported that intensive agricultural using a high rate of in anorganic NPK fertilizer and pesticide, caused declining in soil productivity, soil degradation, and increased environmental pollution. Organic content of these soils are mostly very low, while it is widely know that organic matter is very important to keep physical, chemical, and biological properties of soil as well as soil productivity. However, the quality and quantity of organic matter to be used are important factor determining the impact on the soil. In Ministry of Agriculture Decree (Permentan) No. 28, 2009, a maximum limit of total iron content in organic fertilizer is 8.000 mg kg-1 while most of the current organic fertilizers available in the market exceed this limit. The objectives of the study were to know the quality of organic fertilizer currently available in the market in Java Island and to determine the threshold level of iron that potentially cause iron toxicity in rice. The survey was conducted on May to July 2011 in java Island for survey and collecting a number of organic fertilizer currently marketed and the pot experiment was conducted on May to November 2011 in green house. This experiment using a randomized complete block design with two factors; the types of soil (Endoaquert, Tropaquept, and Hapludult) and organic fertilizer enriched with Fe (FeCl3) in various level. Each treatment was replicated three times. Survey results from 60 samples of granule organic fertilizer taken from several areas in Java Island with 11 parameters, there was indicated two samples (3 % from the total samples) that fulfilled several criteria following of Permentan No. 28, 2009 and no sample (0%) that fulfilled several criteria following of Permentan No. 70, 2011. The pot experiment results showed that the threshold of total iron content in granule organic fertilizer potentially cause iron toxicity for Endoaquert, Tropaquept, and Hapludult were 62.900, 37.300, and 61.100 mg kg-1 respectively. The threshold of total iron content in granule organic fertilizer potentially cause iron toxicity in rice of IR 64 variety with dose 1 ton/ha is 59.500 mg kg-1.
Keyword: Iron, threshold, organic fertilizer, iron toxicity, wetland rice

Judul: Konstruksi aritmetika kurva eliptik F(2m) supersingular dan non-supersingular untuk skema kunci publik ElGamal
Abstrak: Algoritme ElGamal adalah salah satu algoritme kunci publik dengan aritmetik modular p yang mempunyai struktur grip siklik Z(p). Tingkat keanaman algoritme ini terletak pada pemecahan masalah logaritme diskret dari Z(p). Akan tetapi, tingkat keamanan tadi tahun ke tahun semakin menurun yang disebabkan kemampuan pemecahan algoritme diskret semakin meningkat. Untuk memenuhi tingkat keamanan yang memadai dibutuhkan p yang cukup besar yang menyebabkan proses enkripsi dan dekripsi menjadi lambat.
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