• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.319-319
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• 2017

Methane is the main greenhouse gas released from rice paddy field. Methane from paddy fields accounts for 11 % of the global total methane emission. The global warming potential (GWP) of methane is 25 times more than that of carbon dioxide on a mass basis. It is well known that most effective practice to mitigate methane in paddy is related to the water management during rice growing season and the use of organic matters. This study was conducted to investigate the effects of tillage and cultivation method on methane emission in paddy. Tillage (tillage and no-tillage) and cultivation methods (transplanting and direct seeding) were combined tillage-transplanting (T-T), tillage-wet hill seeding (T-W), tillage-dry seeding (T-D) and no-till dry seeding (NT-D) to evaluate methane mitigation efficiency. Daily methane emission was decreased on seeding treatments (T-W, T-D, NT-D) than transplanting treatment (T-T). Amount of methane emission during rice growing season is highest in T-T ($411.7CH_4\;kg\;ha^{-1}y^{-1}$) and lowest in NT-D treatment (89.7). In T-W and T-D treatments, methane emissions were significantly decreased by 36 and 51 % respectively compared with T-T. Methane emissions were highly correlated with the dry weight of whole rice plant ($R^2=0.62{\sim}0.93$). T-T treatment showed highest $R^2$ (0.93) among the four treatments. Rice grain yields did not significantly differ with the tillage and cultivation methods used. These results suggest that direct seeding practice in rice production could mitigate the methane emissions without loss in grain yield.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.340-340
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• 2017

Rice straw is very important to maintain fertility in agricultural soil with several aspects such as carbon and nitrogen cycles in Korea. Recently, concerning about climate change, carbon sequestration in agricultural land has become one of the most interesting and debating issues. Rice straw is most representative source of organic material produced in agricultural sectors. In order to evaluate changes of soil carbon treated by rice straw during cultivating rice in paddy field, we carried out to treat rice straw with 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$ at $50{\times}50{\times}20cm$ blocks made of wood board, and analyze contents of fulvic acid and humic acid form, and total carbon periodically. The experiment was conducted in 2013-2016, and sampled with interval in a month. The organic material was applied to treatment blocks in 2 weeks ago in rice transplanting of each year. Total carbon in beginning time is low as $7.9g\;kg^{-1}$. The contents of total carbon with treatments of rice straw after experiment are recorded as 8.7, 11.2, 9.5, 10.5, and $10.9g\;kg^{-1}$ applied by 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$, respectively. When trend lines were calculated on changes of soil carbon in periods of experiments, The trend equations of soil carbon changes with treatments of 0, 0.5, 1, 1.5, and $2.0ton\;ha^{-1}$ were Y=0.0015X+8.479, Y=0.073X+8.2577, Y=0.0503X+8.4477, Y=0.0822X+8.2103, and Y=0.082X+8.5736. These trends suggested several results. When rice straw was applied in cultivating paddy fields, most carbon in rice straw would be decomposed regardless the amount of rice straw in soil. We calculated sequestration rate of applied rice straw as about 0.1% per year during rice cultivation in paddy fields. It means that if farmer want to increase 1% soil organic matter by using application of rice straw returned after cultivation, famer should apply rice straw continuously for ten years. The change of soil carbon as fulvic acid, humic acid, and humane is showed that only content of carbon as mumine is increased significantly while fulvic acid and humic acid were changed in range of 10 to 30% among total carbon in soil. In conclusion, to sequestrate soil carbon with rice straw, it is important for rice straw to apply continuously every year. The amount of rice straw applied is not much effected to increase soil organic matter.

• 한국약용작물학회:학술대회논문집
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• 2011.09a
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• pp.366-367
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• 2011

• Journal of Biosystems Engineering
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• v.29 no.4
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• pp.293-300
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• 2004

In order to solve the shortage of roughage supply for dairy farm in Korea, the mechanized model system for the production of winter cereal wrap silage in the fellow paddy field was developed in the previous studies. In this study, storage properties after long term storing of the winter cereal wrap silage were investigated. Also, the qualities of the wrap silage which was stored during 4 months were evaluated by sensory testings, analyzing chemical properties(moisture content, pH and organic acids) and investigating the increase of feeding value. The result of this study were summarized as follows; 1. After 300 hours storage, the acid level of the silage decreased slowly to 4.6 -4.8 pH. Also, the temperature was stabilized around 27-28$^{\circ}C$. The silage having below 5.0 pH is a desirable level for the most of good silage. 2. According to the sensory test and chemical property analyzation it was evaluated as the first class silage like a com silage. 3. Also, when the wrap silage are fed to the cattle, the cattle produced milk more 25% than that of conventional feed. 4. As an overall conclusion, winter cereal wrap silage in the fallow paddy field cm be one of the major roughage source in replacement of com and other conventional silage to dairy cattle in Korea.

• Weed & Turfgrass Science
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• v.2 no.3
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• pp.318-321
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• 2013

National Academy of Agricultural Science and eight province Agricultural Research & Extension Services investigated the occurring area of herbicide resistant weeds in paddy field of Korea. In order to estimate the occurring areas of herbicide resistant weeds, we collected paddy soils randomly from 3,200 sites in 2011 and 2012, and treated 30 kg $ha^{-1}$ of pyrazosulfuron-ethyl+pyriminobac-methyl GR to the paddy soil. 176,870 ha, approximately 22.1% of cultivated area excluding organic and eco-friendly cultivated area, was estimated to be infested by SUherbicide resistant paddy field weeds. Several species of resistant weeds were occurred at Jeonranam-do with 44.3%, followed by 30.5% at Chungchungnam-do, 27.8% at Chungchungbuk-do, and 24.5% at Jeonrabuk-do, respectively. Monochoria vaginalis showed the highest distribution with 57,018 ha, 32.2% followed by Scirpus juncoides, and Lindernia procumbens, respectively.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1292-1298
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• 2022

Soil autotrophic bacterial communities play a significant role in the soil carbon (C) cycle in paddy fields, but little is known about how rhizosphere soil microorganisms respond to different long-term (35 years) fertilization practices under double rice cropping ecosystems in southern China. Here, we investigated the variation characteristics of rhizosphere soil RubisCO gene cbbL in the double rice ecosystems of in southern China where such fertilization practices are used. For this experiment we set up the following fertilizer regime: without any fertilizer input as a control (CK), inorganic fertilizer (MF), straw returning (RF), and organic and inorganic fertilizer (OM). We found that abundances of cbbL, 16S rRNA genes and RubisCO activity in rhizosphere soil with OM, RF and MF treatments were significantly higher than that of CK treatment. The abundances of cbbL and 16S rRNA genes in rhizosphere soil with OM treatment were 5.46 and 3.64 times higher than that of CK treatment, respectively. Rhizosphere soil RubisCO activity with OM and RF treatments increased by 50.56 and 45.22%, compared to CK treatment. Shannon and Chao1 indices for rhizosphere soil cbbL libraries with RF and OM treatments increased by 44.28, 28.56, 29.60, and 23.13% compared to CK treatment. Rhizosphere soil cbbL sequences with MF, RF and OM treatments mainly belonged to Variovorax paradoxus, uncultured proteobacterium, Ralstonia pickettii, Thermononospora curvata, and Azoarcus sp.KH33C. Meanwhile, cbbL-carrying bacterial composition was obviously influenced by soil bulk density, rhizosphere soil dissolved organic C, soil organic C, and microbial biomass C contents. Fertilizer practices were the principal factor influencing rhizosphere soil cbbL-carrying bacterial communities. These results showed that rhizosphere soil autotrophic bacterial communities were significantly changed under conditions of different long-term fertilization practices Therefore, increasing rhizosphere soil autotrophic bacteria community with crop residue and organic manure practices was found to be beneficial for management of double rice ecosystems in southern China.

• The Journal of Natural Sciences
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• v.5 no.2
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• pp.49-62
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• 1992

This study was carried out to investigate the emergence, growth and yield components in rice inassoccation with Several cultivation methods direct sowing flooded paddy field(DSF), direct sowing by airplane(DSA), direct sowing in dry paddy field(DSD), 8days seedling planting(8DS), and 35days seedlingplanting(35DS). Also this study was attempeted to know the effects of calcium peroxide on germinationand early growth of rice under different soil conditions, seeding depth, application of organic matter,indirect sowing flooded paddy field.1. Rate of emergence was 73% in DSF, 70% in DSA, 62% in DSD, respectively, under the different cultivation method of rice in reclaimed paddy field.2. Degree of lodging in relation to cultivation was 5 at both DSF and DSA, 3 at DSD, 2 at both 8DS and 35DS respectively.3. Maximum tiller number was 568 per m2 at DSF and 527 at DSA. Heating was delayed for 4 days at DSF, 8 days at DSD and 2 days at 8DS as comparison with that at 35DS.4. Yield was higher 1% to 3% at DSF than that at DSA and DSD while decreased by 12% as compared with that of seedling planting.5. Total dry weight of seedling was decreased by 57% at 8DS, 60% at DSF 63% at DSD, respectively, under 0.3% of salinity. Ratio of decreasing in dry weight was higher with high salinity.6. The amount of O2 released was recorded highest to 2 to 3days after irrigatition, thereafter remaining constant to 10 days after irrigatition.7. The optimum coating amount of calcium peroxide for germination was a half of rice seed weight with 1 cm sowing depth and one-fold with 2-cm sowing depth when rice straw was not applied. With rice straw applied, on the other hand, the amount of peroxide was one-fold with 1-cm sowing depth. It was found that, under the condition of applied 600kg/10a, of 2-cm soil depth with rice straw calcium peroxide coating had no effect on emergence of rice seedling.8. In reclaimed paddy field, lodging degree was 7 with direct sowing by machine and 9 with direct sowing by hand.9. Yield was increased by 5% by applying rice straw with direct sowing by machine.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.528-534
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• 2015

Green manure crops have been well recognized as the alternative for chemical fertilizer, especially N fertilizer, because of its positive effect on soil and the environment. Hairy vetch and green barley are the most popular crops for cultivation of rice in paddy field. This study was conducted to evaluate effects of hairy vetch and green barley on soil microbial community and chemical properties during short-term application (three years). For this study, treatments were composed of hairy vetch (Hv), green barley (Gb), hairy vetch + green barley (Hv+Gb), and chemical fertilizer without green manure crops (Con.). Hv+Gb treatment showed the highest microbial biomass among treatments. Principal component analysis (PCA) showed that PC1 (73.0 %) was affected by microbial biomass and PC2 (21.5 %) was affected by fungi, cy19:0/18:$1{\omega}7c$ (stress indicator). Combined treatment with hairy vetch and green barley could be more efficient than green manure crop treatment as well as chemical fertilizer treatment for improvement of soil microorganisms.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.85-94
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• 2007

To determine the influence of food waste compost (FWC) application on paddy soil, FWC was applied to the paddy soil and then compared with farmer's practice as to the effects on rice and soil environment. Initially, pig manure compost (PMC) had high content of phosphorus ($15g\;kg^{-1}$) and potassium ($23g\;kg^{-1}$), while FWC had high content of total nitrogen ($13g\;kg^{-1}$) and salinity ($18.5g\;kg^{-1}$). Comparison was also made between chemical fertilizer and FWC use as a trial in the paddy field under the clay loam and sandy loam soil. In the panicle formation stage, chemical fertilizer application was proper in clay loam while PMC application was proper in sandy loam. However, chemical fertilizer produced higher yield compared to compost treatment, both on clay loam and sandy loam with 20~25% and 17~19%, respectively. The lower yield in sandy loam maybe due to slow mineralization of compost such that the crop did not effectively use it. Organic matter content in paddy soil after experiment was higher in FWC and PMC plots compared to that in chemical fertilizer plots. But the other soil properties were comparable. Therefore, the FWC compost had little effect on soil when it use as a trial in paddy field. Likewise, after the application of FWC as a trial, analysis of nitrate nitrogen and ammonium nitrogen in the surface water and 60 cm depth of paddy soil water nine days after planting was done. Results revealed that concentration of ammonium nitrogen was similar to irrigation water while nitrate nitrogen concentration was not detected, and hence did not contribute to water pollution. It is concluded that the application of FWC in the paddy field had not affected on environmental pollution in the paddy field. But its use as compost during rice culture reduced yield quantity. Such study should include selection of compost material, amount and method of compost application.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.211-214
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• 1998

Changes in physico-chemical properties and major nutrient contents were investigated in the soil of paddy fields during fallow period. Weed vegetation change in the fallow paddy fields was also examined. As the fallow period became longer, organic matter content in the paddy soil has gradually increased. Soil pH of the paddy fields has not changed until three years of fallow period and thereafter slightly increased. Cation exchange capacity of the paddy soil, and exchangeable N, K, Ca and Mg contents in the soil tended to decrease until three years of fallow period and then increase with the prolonged fallow period. As the fallow period became longer, available $P_2O_5$ content in the paddy soil has continuously decreased. Available $SiO_2$ content in the paddy soil has not changed until three years of fallow period and thereafter increased. The vegetation in the fallow paddy fields have mostly been occupied by the weeds of the Gramineae, Cyperaceae, and Compositae. As the fallow period became longer, the weeds of the Polygonaceae and Juncaceae have increased, whereas the weeds of the Leguminosae, Commelinaceae, Pontederiaceae, and Onagraceae have gradually disappeared. However, the weeds of the Gramineae and Cyperaceae have always been dominant in the paddy fields during the fallow paddy period.