• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.141-148
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• 2002

This study was performed to examine the effects of rice straw as bulking materials on temperature, pH, weight and volume reduction, porosity, C/N ratio, salinity, and conductivity in aerobic composting of food wastes. Volume ratios of food wastes to rice straw in reactor control, RS-1, RS-2, RS-2 and RS-4 were 4:0, 4:1. 4:2. 4:3 and 4:4, respectively. Reactors were operated for 24days with 1 hour stirring by lrpm and 2hours aeration per day. The values of pH of food wastes and rice straw were 4.39 and 7.4, respectively. The lowering of the volume ratio of food wastes to rice straw resulted in the high reaction temperature and the fast weight and volume reduction rates. C/N ratio in control was larger than that in rice straw containing reactors. Salinity and conductivity in reactors were condensed and increased by reaction days.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.857-868
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• 2019

A flooded rice field is one of the significant sources of anthropogenic methane (CH₄) with the intensity of the emissions dependent on management practices. Incorporation of rice straw, which is one of the organic amendments, induces the increase of methane emissions during the flooding season. In this study, we measured of methane emission according to applications of rice straw in different soil textures during a cultivation period in 2017 and 2018. The fallow treatments were non application of rice straw (NA), spring plowing after spring spreading of rice straw (SPSA), spring plowing after previous autumn spreading of rice straw (SPAA), and autumn plowing after previous autumn spreading of rice straw (APAA). The SPSA treatment emitted the highest total methane from loam soil in both 2017 (596.7 CH₄ kg ha^-1) and 2018 (795.4 CH₄ kg ha^-1). The same trend was observed in silt clay loam soil; the SPSA treatment still emitted the highest amount of methane in both 2017 (845.9 CH₄ kg ha^-1) and 2018 (1,071.7 CH₄ kg ha^-1). The lowest emission among the rice straw incorporated plots came from the APAA treatment for both soil texture types in all the seasons. The conversion factors of the SPAA were 0.79 and 0.65 from the loam and silt clay loam soils, respectively. Relatedly, the conversion factors of the APAA were 0.71 and 0.43 from the loam and silt clay loam soils, respectively. The above observations mean therefore that incorporation of rice straw early in the fallow reduces methane emissions in the main rice growing season.

• Journal of the Regional Association of Architectural Institute of Korea
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• v.21 no.5
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• pp.117-124
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• 2019

When manufacturing concrete, several mineral admixture is added to improve the basic physical property and durability and to make economical concrete. Such mineral admixture includes fly ash, granulated blast furnace slag, silica fume, etc., and not only the studies about mixing these mineral admixtures but also the studies for the development of new materials have been steadily in progress. Recently, some researchers have found, as a part of the development of new materials, the rice straw ash can also be used as a pozzolanic material for concrete considering similar chemical properties of rice straw ash to that of rice husk ash. But there has been insufficient amount of study about it. So, this study was to investigate the possibility as mineral admixture of agriculture by-product, by analyzing properties of concretes using rice straw ash with replacement ratio in comparison with other mineral admixture. In order to measure amount of SiO2 of rice straw ash, XRF(X-ray fluorescence) analysis was tested. For the measure pozzolanic reaction of rice straw ash, pH change and color change was tested according to curing day. Also to evaluate properties of concrete using rice straw ash, slump test, air contents test and compressive strength was tested.

• Journal of the Korean Society of Tobacco Science
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• v.12 no.2
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• pp.85-90
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• 1990

Pot experiment was conducted to find out the effect of decomposing degree of rice straw on growth characteristics of flue-cured tobacco, NC82. Tobacco growth was hindered by fresh straw of rice application. Generally, it was known that if organic matter of high Carbon/Nitrogen ratio had applied in soil, there was temporary nitrogen deficiency in plant caused by soil microorganism utilized nitrogen contained organic matter. In pot experiment, it was supposed that tobacco growth hindered by fresh straw of rice application was not nitrogen deficiency by soil microorganism, but gas toxicity by fresh straw of rice application.

• Journal of Forest and Environmental Science
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• v.31 no.2
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• pp.119-125
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• 2015

This study examined the effects of rice straw steaming time and mixing ratio between rice straw and wood particle on the properties of mixed particle board from Acacia mangium Willd wood and rice straw. Rice straw and Acacia mangium Willd wood were collected in Hanoi, Vietnam. The particle board was three-layer particle board with the structural ratio of 1:3:1. The thickness, density and board size of the particle board were 18 mm, $0.7g/cm^3$, and $800{\times}800{\times}18$ (mm, including trimming), respectively. A resin mixture between commercial Urea-formaldehyde (U-F) adhesive and methylene diphenyl isocyanate (MDI) adhesive was used with a dosage of 12% for the core layer and 14% for the surface layer. In this experimental design, the steaming time for rice straw was 15, 30, 45, 60, and 75 minutes at $100^{\circ}C$. The rice straw-wood mixing ratio was 10, 20, 30, 40, and 50%. The results showed that both mixing ratio and steaming time affect the properties of the particleboard, but the mixing ratio has a stronger impact. A higher mixing ratio and a longer steaming time resulted in a better quality of particleboard. The optimal steaming time for rice straw was 46.12 minutes with the straw-wood mixing ratio of 29.85% with the following characteristics of the particle board: the modulus of rupture (MOR) of 14.64 MPa, internal bond strength (IB) of 0.382 MPa, thickness swelling (TS) of 8.83%, and board density of $0.7-0.7g/cm^3$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.49-55
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• 1997

For the labor-saving cultivation of barley in rice-barley double cropping system in paddy field, a series of expriments on the effect of rice straw application were carried out at the National Yeongnam Agricultural Experiment Station from 1992 to 1993. The affection of phenol compounds released from fresh rice straw could be lessened when seeded under rice straw in the soil and that made emergence rate increase by 11％, compared with that on application on the rice straw. Although utilization of rice straw as an organic material caused the poor growth of barley in early stage, it could be enhanced the culm breaking strength. On this reason, affected by rice straw, grain yield was increased from 8％ in common barley and up to 20％ in malting barley. The more nitrogen, CaO$_2$2 and SiO$_2$ applied, the more decomposition of rice straw accelerated from 2％ to 6.9％. On the application of rice straw as an organic material in malting barely cultivation, the content of crude protein was decreased while 1,000-grain-weight and grain assortment was increased.

• Applied Biological Chemistry
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• v.27
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• pp.56-67
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• 1984

As in many other country, the use of organic matter in Korea has long history. Farmers understand the value of organic matter as the source of plant nutrient and soil improving agent in general. Since 50 years ago, the sources of organic matter in paddy soils were compost, rice and barly straw, green manure, animal waste, fish and beancake, etc.. Application of green manures such as vetch and chinese milk vetch showed no significant effect on the yield of brown rice in paddy soil. On the other hand, the effects of compost and rice straw showed more significant on the yield of brown rice in paddy soil. Application of rice straw in rice cultivation is commonly made at different times between harvest, early spring and several weeks before transplanting. Considering the suitable paddy soil for application of rice straw under well to moderately well drained soil, the yield was pronounced more than poorly drained soil. Based on laboratory and field experimants, application of rice straw promoted the decrease of oxidation-reduction potential in well to moderately well drained soil. This results to be enhanced the release of some mineral nutrients,. such as potassium, calcium, silicon, and increase of availability of soil phosphorus. In the field experiments, results obtained from nitrogen fraction on the immobilization-mineralization of the tracer nitrogen applied in paddy soil,the amount and index of organic nitrogen incoporated in soil was more pronounced in rice straw application than control. Rice straw and its transformation products incoporated in the soil, provided the inflow of energy necessary to maintain heterotrophic microbes activities. Rice straw and its transformation products, especially soluble carbohydrate, enhanced the population of free-living heterotrophic $N_2$ - fixing microbes. Moreover, rice straw and its transformation products in paddy soil, enhanced the activities of soil enzymes such as dehydrogenase and urease.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.906-912
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• 2000

The effect of ammonia treatment and rice bran supplementation on the in situ rumen degradation of rice straw was determined using three Japanese Corriedale wethers fitted with permanent rumen cannula. About 4 g samples of diets containing 100% untreated rice straw (URS); 100% ammonia treated rice straw (ARS); 65% URS+30% rice bran (RB)+5% soybean meal (SBM) (T1); and 85% ARS+15% RB (T2) were incubated at 0, 4, 8, 16, 24, 48, 72, and 96 hours in the rumen of sheep to measure dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) degradability. The DM disappearance of ARS based diets were about 20% higher than that of URS based diets. Rice bran supplementation improved DM disappearance of URS but not on ammoniated straw. Degradation parameters showed that ammoniation increased rate (c) of straw degradation resulting to higher DM and fiber degradability but RB supplementation did not. ARS gave similar DM and CP solubility and effective rumen degradability (ED) with that of the supplemented groups indicating that ammoniation alone can give the same effect on rumen degradability of sheep receiving low quality roughage. All degradation parameters for NDF were consistently higher in ARS based-diets indicating improved fiber solubility. Rice bran supplementation did not affect degradation characteristics of the diets except on soluble DM and CP fraction (A) of URS but not on ARS.

• Journal of Environmental Health Sciences
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• v.29 no.1
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• pp.43-50
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• 2003

This study was performed to compare the effects of rice straw and towage sludge cake as bulking materials on temperature, pH, weight and volume reduction, porosity, C/N ratio, salinity, and conductivity in aerobic composting of food wastes. Volume ratios of food wastes to rice straw in reactor control, RS-1, RS-2, RS-3 and RS-4 were 4:0, 4:1, 4:2, 4:3 and 4:4, respectively. Weight ratios of food wastes to sewage sludge rake in reactor control, SL-1, SL-2, SL-3 and SL-4 were 4:0, 4:1, 4:2, 4:3 and 4:4, respectively. Reactors were operated for 24 days with 1 hour stirring by 1 rpm and 2 hours aeration per day. The values of pH of food waters, rice straw and sewage sludge cake were 4.39, 7.40 and 5.79, respectively. The lowering of the volume ratio of food wastes to rice straw resulted in the high reaction temperature and the fast weight and volume reduction rates. The lowering of the weight ratio of food wastes to sewage sludge cake resulted in the slow weight and volume reduction rates. C/N ratio in control was larger than that in rice straw containing reactors, and that in rice straw containing reactors was larger than that in sewage sludge cake containing reactors. Salinity and conductivity in reactors were condensed and increased by reaction days.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.368-373
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• 2003

This experiment was conducted to examine the effects on the composition and rumen degradation in sacco of rice straw treated with animal urine (1 l of 2.9 g N/kg DM straw) and urea plus calcium hydroxide (2% urea plus 0.5% $Ca(OH)_2$/kg DM straw) as a cheap and relatively safe alternative for ammonia (3% ammonia solution/kg DM straw). Mold occurred in urine treated straw, but other treatments were apparently mold-free. All treatments significantly (p<0.05) increased CP content in the straw compared with untreated one. Ammonia-treated straw contained CP at about twice that in urine or urea-calcium hydroxide treated straw. NDF and hemicellulose contents decreased significantly (p<0.05) in all treatments, while ADF and cellulose showed no differences compared with untreated straw. The degradable fraction of DM, CP, NDF, hemicellulose and cellulose was significantly (p<0.05) increased for ammonia and urea-calcium hydroxide treatments than for urine treated or untreated straw except for CP of urine treated straw. Chemical treatment of rice straw increased the readily degradable fraction of CP, while it decreased the slowly degradable fraction for urine or urea-calcium hydroxide treated rice straw. The degradation rate of hemicellulose was significantly (p<0.05) increased for ammonia and urea-calcium hydroxide treatments compared to urine treated or untreated straw. However, no effect on cellulose degradation rate was found by any of the treatments. There was no improvement in the degradation kinetics caused by the urine treatment despite the improvement of the chemical composition. Although the improvement in rumen degradability was less in the urea-calcium hydroxide treatment than in the ammonia treatment, its use may be more desirable because it is less expensive to obtain, less hazardous nature, and readily available. For further improvement it is necessary to investigate the supplementation of slowly degradable nitrogen to ureacalcium hydroxide treated rice straw diet.