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: Aplikasi pupuk anorganik dan pupuk organik hayati pada budidaya padi sri (System of Rice Intensification)
Abstrak: Excessive use of inorganic fertilizers mainly NPK cause soil degradation, environment pollution, lower yield decreased production, and reduce soil biological activity. System of rice intensification is one method of rice cultivation. SRI main principles are seed transplanting at young age (7-11 days old), transplanting use single seedling methode, seedlings at wide plant spacing ≥ 25x25 cm, intermittent irrigation and field conditions are not flooded, and reduction of chemical fertilizers used and replaced by organic fertilizer. This research was conducted from April 2010 to January 2011 in Situgede Village, West Bogor District, Bogor. The research design used split plot randomized complete block design with three blocks. Two rice cultivation system as the main plot and five combinations of fertilizer application as sub plot. The result showed that the maximum number of tillers on SRI method higher at 25,8 tillers/hill or an increase of 64,33% compared with conventional methods. Wet and dry shoot weight of wet and dry weight of root is greater in successive SRI method of 13,3%, 19,1%, 18,4% and 41,8% compared with the conventional method. The number of productive tillers, grain number/panicle, 1000 grains weight, root wet weight and dry grain at SRI method was higher than those in conventional method respectively 58,6%, 37,0%, 2,5%, 25,1% and 32,6%. Uptake of N and P in the SRI method higher at 72,0% and 100% compared to conventional method. Application 50% inorganic fertilizer + 200 kg bio-organic fertilizer, producing more fresh weight biomass, plant dry weight, wet weight and dry weight, number of productive tillers, 1000 grain weight respectively 13,9%, 42,0 %, 49,8%, 74,0%, 10,7% and 2,48% compared with the dosage recommendations dose or 100% inorganic fertilizer. N, P and K uptake at 50% inorganic fertilizer + 200 kg of bio-organic fertilizer treatment higher (55,6%, 66,7% and 46,2%) than the foal recommendation dose of inorganic fertilizer. Bio-organic fertilizer can be used as substitute of NPK fertilizer.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh.
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. ,,,
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular.