• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.5
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• pp.318-324
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• 2000

Field experiment was conducted on a sandy clay loam paddy field in the Experimental Farm of the Kangwon National University for four years from 1995 to 1998 to evaluate the effect of different nitrogen fertilizers on soil property and rice yield. The size of each experimental plot was 75 m2. Basal application of fertilizer to the paddy field was on late April, and rice (cv. Odae) was sown with drill seeding on early May. Irrigation was done at 3 leaf stages after rice seeding. Electrical conductivity in soils treated with phosphate- and resin coated slow release fertilizers were relatively greater than those of the other fertilizer application. Available $P_2O_5$ concentration in soils after rice harvest increased significantly compared that in soil before field trial. Rice yield in transplanting culture were $6.516kg\;ha^{-1}$. The rice yield in the direct seeded paddy was 81.9 percents of the yield in the transplanted paddy. The rice yield in phosphate coated slow release fertilizer was the highest among various fertilizer trials in directly seeded dry paddy, while rice yield was the lowest in the organic fertilizer plus urea application. Rice yield between organic fertilizer plus urea and organic fertilizer application were not significantly different. The green manuring effect of rye in the direct seeded rice paddy in Chuncheon was low due to low temperature and short growth period.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.32 no.1
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• pp.57-64
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• 2000

As a method to reduce the sue of agricultural chemicals mulching with thin plastic films has been commonly practised for many years. Although use of plastic films for mulching is very effective in preventing herb growth it is almost impossible to remove all of the plastic films from the agricultural lands and the remaining films eventually contaminate the soils. Therefore, it is very imperative to develop a mulching material that decomposes completely to prevent soil pollution problems and to enhance the competitive edge of domestic agriculture. In this paper the possibilities of using strength resins for improving strength properties of mulch papers made from old corrugated containers were examined. Also mulch papers have been produced and applied for practical farming in upland as well as paddy field. Result showed that the usage of 0.7% of wet strength additives was effective for wet and dry strength of mulch paper. Changes of various process parameters including freeness, cationic demand, one pass retention, nitrogen content, etc. that occurred during trial production of mulch paper have been examined and discussed . It was found that paper mulching was very effective for weed control both in upland field and paddy filed.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.145-150
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• 2007

This study was conducted to evaluate the application effects of phospho-gypsum fertilizer (PGF) as reclamation material in the newly reclaimed paddy fields located in Goheung and Youngam, Jeonnam province in Korea. The PGF used in this experiment was produced by Namhae Chemical Co. as the name of Soil-Saver$^{TM}$. Prior to rice transplanting, the PGF was applied as soil amendment as the amount of $3,000kg\;ha^{-1}$. The PGF increases rice plant height and number of tiller at the heading stage by 119.9 cm and 9.1, respectively, in Youngam area. The harvest index of brown rice increased up to 5 and 13% more in the PGF applied paddy field from both sites than in the non-application of PGF at paddy field before rice transplanting, and the ripening ratio in increased in both sites to 81 and 90%. Protein content of brown rice was also greater than in the non-application of PGF at the both sites. For the effects of the reclamation by PGF in the paddy field soils, we found that PGF reduced exchangeable Na to 18 and 28% for both sites, respectively, and increased exchangeable Ca and $SO_4$. And we found relatively higher amounts of $K_2O$, CaO and MgO in the rice plants from both sites applied with PGF.

• Economic and Environmental Geology
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• v.31 no.6
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• pp.499-508
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• 1998

The Imgok Creek is located in the Gangreung coal field, which has been known that sulfides are more abundant than other coal fields in Korea, and it has been severly contaminated by acid mine drainage (AMD) discharging from the abandoned coal mines, such as the Youngdong, the Dongduk and the Waryong coal mines. The purposes of this study are to synthetically assess the contamination of natural water, stream sediment and cultivated soils, and to provide the basic data for AMD treatment. Geochemical samples were collected in December, 1996 (dry season) and April, 1997 (after three day's rainfall). TDS of the Youngdong mine water was remarkably higher than those of other mine waters. In the Imgok Creek, concentrations of most elements, except Fe decreased with distance by dilution caused by the inflow of uncontaminated tributaries. From the results of NAMDI and $I_{geo}$ calculation, the Youngdong coal mine was the main contamination source of the study area. Groundwater pollution was not yet confirmed in this study and the paddy and farm land soils were also not yet contaminated by mining activity based on the pollution index ranging from 0.27 to 0.47.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.3
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• pp.175-181
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• 2000

This study was carried out to investigate the change of soil physical properties in long-term fertilized paddy soils with a Fine silty family of Typic Halpaqueps (Pyeongtaeg series). Treatments fertilized consisted of no fertilizer, compost, NPK, NPK+compost for thirty one years and of NPK+silicate for seventeen years. Water stable aggregate and degree of aggregate stability, which were higher in surface-soil than sub-soil, were high in order of NPK + compost > NPK + silicate > compost > NPK > no fertilizer plot. The ratio of aggregate larger than 0.5mm was high at compost and silicate plots but that smaller than 0.5mm was high at no fertilizer and NPK plots. And this aggregate stability showed negative correlation with soil hardness and bulk density ; positive correlation with sedimentation volume of soils in water. Sedimentation volume of soils in water was a little higher in surface-soil than sub-soil and in wet soil than dry soil, respectively. Pore space ratio and water retention capacity of soils were the most increased by the application of compost and not affected by silicate as in cases of liquid limit and plastic limit. Ignition loss of soils was high in order of NPK + compost > compost > NPK + silicate > NPK > no fertilizer plot. And field shattering ratio of soil mass smaller than 25.4mm was relatively high in NPK + compost, compost, and silicate plots.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.229-233
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• 2007

A long-term rice paddy field, which is located in the National Institute of Crop Science (Suwon city, Korea) has been managed for studying of fertilization and composting impact on paddy soil fertility since 1954. The objective of this research was to evaluate soil quality through dehydrogenase analysis in long-term paddy soil treatment plots, such as control, N fertilization (N), NPK fertilization (NPK), and rice straw compost with NPK (CNPK). Dehydrogenase-producing bacterial population developing red-colored triphenyl formazan (TPF) was highly correlated to the dehydrogenase activity in rice paddy soils sampled prior to waterlog. The dehydrogenase-producing bacterial population and dehydrogenase activity was comparatively high in plots of NPK, and CNPK, which organic matter content was relatively high.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.3
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• pp.216-222
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• 2013

Fertilizer management has the potential to promote the storage of carbon and nitrogen in agricultural soils and thus may contribute to crop sustainability and mitigation of global warming. In this study, the effects of fertilizer practices [no fertilizer (Control), chemical fertilizer (NPK), Compost, and chemical fertilizer plus compost] on soil total carbon (TC) and total nitrogen (TN) contents in inner soil profiles of paddy soil at 0-60 cm depth were examined by using long-term field experimental site at $42^{nd}$ years after installation. TC and TN concentrations of the treatments which included N input (NPK, Compost, NPK+Compost) in plow layer (0-15 cm) ranged from 19.0 to 26.4 g $kg^{-1}$ and 2.15 to 2.53 g $kg^{-1}$, respectively. Compared with control treatment, SOC (soil organic C) and TN concentrations were increased by 24.1 and 31.0%, 57.6 and 49.7%, and 72.2 and 54.5% for NPK, Compost, and NPK+Compost, respectively. However, long term fertilization significantly influenced TC concentration and pools to 30 cm depth. TC and TN pools for NPK, Compost, NPK+Compost in 0-30 cm depth ranged from 44.8 to 56.8 Mg $ha^{-1}$ and 5.78 to 6.49 Mg $ha^{-1}$, respectively. TC and TN pools were greater by 10.5 and 21.4%, 30.3 and 29.6%, and 39.9 and 36.3% in N input treatments (NPK, Compost, NPK+Compost) than in control treatment. These resulted from the formation and stability of aggregate in paddy soil with continuous mono rice cultivation. Therefore, fertilization practice could contribute to the storage of C and N in paddy soil, especially, organic amendments with chemical fertilizers may be alternative practices to sequester carbon and nitrogen in agricultural soil.

• Journal of Soil and Groundwater Environment
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• v.20 no.7
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• pp.61-69
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• 2015

This study was performed to provide fundamental data to establish the new soil pollution standards and the soil contamination management plans in a rational manner. The distribution characteristics of new soil contaminants such as barium (Ba) and chromium (Cr) in soils (n=140) were investigated in relation to land-use classification and geological features. Also, the sequential extraction test was conducted to evaluate fate and mobility of new soil contaminants. The soil samples taken from 140 sites were analyzed to survey distribution levels of selected new soil contaminants. The average concentration and range for hazardous metals (Ba, Cr) were Ba 128.946 (26.757~489.587) mg/kg, Cr 30.121 (2.579~132.783) mg/kg. Based on land use classification, the highest Ba concentration was found in factory soils, followed by dry field and park soils, while Cr concentration was highest in rice paddy soils, followed by dry field and factory soils. Within 10 geological units investigated the highest Ba and Cr concentrations were observed in the soils from Okcheon group and metamorphic rocks, respectively. The BCR (European Community Bureau of Reference) sequential extraction was conducted to identify chemical distributional existence of 2 elements of soils from each geological unit. Ba in soils is mainly assumed to exists as reducible form (such as BaSO₄, BaCO₃) and Cr in soils mainly is assumed to exist as residual form (such as Cr₂O₃, Cr_xFe_1-x(OH)₃(x < 1)).