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: Pengaruh Perbedaan Karakteristik Kimia dan  Mineral serta Penambahan Bahan Organik terhadap Pertumbuhan dan Produksi  Padi yang Ditanam dengan Metode SRI
Abstrak: The necessity of food especially rice increase with increasing in human population. One of a very popular system in the cultivating of paddy is the System of Rice Intensification (SRI). Although SRI is believed can increase the paddy production without inorganic fertilizer and optimizing water use, but there are several problems which has not been fully understand yet in order to apply SRI, especially about the land condition. This research was aimed to study mineralogical and chemical soil characteristics and organic matter application in order to support the growth and the production of paddy cultivating by comparing SRI and conventional method. Soil samples were collected from four locations i.e: Cihideung, Bogor (Chd, Bgr), Sindangbarang, Bogor (Sbr, Bgr), Margakaya, Karawang (Mgk, Krw) and Bobojong, Cianjur (Bbj, Cjr), two water management levels, i.e: convensional (K) and SRI with irrigation during five days (S). Each water management levels were combined with two treatments of organic matter applications, i.e: plus compost application (B1) and without compost application (BO). Treatments were desained in Factorial Completely Random Design with 16 treatments and three times replications. Totally there were 48 experimental units. Chemical properties (C-organic, total N, and K) of Bobojong soil showed better result than the other soils, and the texture of Cianjur soil was silty clay. Quartz was the most dominant mineral in sand fraction for all soils, and kaolinite was the most abundant mineral in clay fraction. It was also found easily weathered mineral which show that natural fertility in the research location were high, especially on Sindangbarang and Cianjur soils. Compost application 7 ton/ha was not significantly different in increasing the production and the growth of paddy. Water irrigation using SRI method during five days also can not increase the production and the growth of paddy, except if both treatments were combined. Meanwhile, based on the production and the growth parameters, Sindangbarang (Bogor) soil showed better response for SRI application than other soil. SRI application in different soils gave variety results for paddy production.
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Judul: Penyelesaian Masalah Pelabelan Graf vertex Magic pada Graf Cycle Sederhana
Abstrak: Graf vertex magic adalah suatu graf memiliki nilai bilangan magic yang sama pada masing-masing vertex yang berbeda. Graf cycle sederhana adalah suatu walk tertutup yang mengandung setidaknya tiga vertex, semua vertex-nya berbeda dan setiap vertex terhubungkan oleh satu edge.
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