• Journal of Applied Biological Chemistry
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• v.42 no.1
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• pp.29-33
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• 1999

The present study examined annual runoff loading of nitrogen and phosphorus in the paddy field from 1 May, 1997 to 30 April, 1998. In the investigated area, the amount of rainfall was 1,095.6 mm and 414.6 mm during cropping season and non-cropping season. The annual rainfall was 1,510.2 mm. The total amount of runoff water was 1,043.2 mm and 281.0mm during cropping season and non-cropping season, and the added total amount of runoff water during two seasons was 1,324.2 mm. The runoff loading of nutrients caused by runoff water was measured as follows. The total-N was 149.23 and $8.67kg\;ha^{-1}$ (total amount=$157.90kg^{-1}ha^{-1}yr^{-1}$), the ammonia-N 102.98 and $4.44kg\;ha^{-1}$ ($107.42kg^{-1}ha^{-1}yr^{-1}$), the nitrate-N 28.45 and $1.23kg\;ha^{-1}$ ($29.68kg^{-1}ha^{-1}yr^{-1}$), the total-P 4.16 and $0.38kg\;ha^{-1}$ ($4.54kg^{-1}ha^{-1}yr^{-1}$) during cropping and non-cropping season respectively. When the loss ratio was calculated based on amounts of chemical fertilizer, about 68.6% of nitrogen and 16.7% of phosphorus was lost by runoff from applied fertilizer amount.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.253-259
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• 2015

BACKGROUND: During the off-season, the cultivation of Chinese cabbage and water dropwort is often used to desalinize plastic film house soils. The objective of this study was to verify the effect of double-cropping systems on the salt removal in oriental melon cultivated plastic film house soils.METHODS AND RESULTS: Electrical conductivity (EC) and soluble salt contents were measured in soils collected from plastic film houses of oriental melon cultivation before and after the off-season crop cultivation. Also the same measurements were performed in the next oriental melon season to estimate the desalinization effect of double-cropping systems. During the cultivation of Chinese cabbage under open-field condition, EC_eof surface soil was reduced from 6.0 to 0.8 dS/m. Double-cropping of water dropwort in flooded soil was also efficient in removing the salts accumulated during oriental melon cultivation. In the house soils where salts were removed during the off-season crop cultivation, soil EC_ewas maintained below 3 dS/m during the next oriental melon cultivation season.CONCLUSION: The off-season cropping under open-field or flooded condition was effective in desalinization of plastic film house soils. Since the salt removal effect is not expected to last for several years, the double-cropping system should be introduced every season to maintain soil EC below the critical level.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.333-333
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• 2017

This study was conducted to establish of cropping system for year-round forage crops production in east-southern part of Korea and investigated their productivity and feed values. Cropping systems were tested in experiment using oat (cv. Highspeed and Darkhorse) in spring and autumn season, corn (cv. Kwangpyeongok) and sorghum (ss-450) in summer season and rye (cv. Gogu) and triticale (cv. Joseong) in winter season. Considering the forage productivity and feed value such as acid detergent fiber (ADF), neutral detergent fiber (NDF) and total digestive nutrients (TDN), this result suggest that three cropping system for year-round forage crops production. The combinations with triticale (winter), corn or sorghum (summer) and oat (autumn) were would be suitable ones. And also the combinations with rye (winter), corn or sorghum (summer) and oat (autumn) were would be suitable. If forage crops cultivation was started in spring season, the combinations with oat (spring), oat (autumn), triticale or rye (winter), corn or sorghum (summer) and oat (autumn) were would be appropriable. For the more suitable cropping system, we are proceeding on verification experiment of year-round forage crops.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.3
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• pp.95-102
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• 2000

The northward shift of the cultivation region of winter barley has been considered because of consecutive warm winters from the middle of 1980's. There was 1.02$^{\circ}C$ rise in mean air temperature during winter barley cropping season from 1975 to 1998. During this period, the maximum air temperature affected the mean air temperature rise rather than the minimum air temperature. The amount of mean precipitation was 513.3 mm during winter barley cropping season from 1975 to 1998 and was least in 1992. Sunshine hours has increased little by little in the all regions except rural regions. The air temperature during winter barley cropping season from 1987 to 1999 in which the winter was warm was higher than the normal air temperature(1961~1990). On the other hand, the air temperature during winter barley cropping season from 1974 through 1986 was similar to the normal air temperature. The amount of mean precipitation during winter barley cropping season from 1987 through 1999 was similar to the normal precipitation except April. During this period, the amount of mean precipitation of April was lower by 26 mm than the normal year(1961~1990). Sunshine hours during winter barley cropping season from 1987 to 1999 decreased generally in comparison with a normal year. Considering the air temperature rise during wintering from 1987 to 1998, it might be possible to extend the cropping area of winter barley northward.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.3
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• pp.220-225
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• 1991

Four cropping systems, soybean mono-cropping, Cassia tora mono-cropping, soybean-C. tora companion cropping and soybean-C. tora intercropping, were compared for number of soil nematodes and soybean growth in upland field in 1986. Soybean was cultivated as an after-crop of four different cropping systems from 1987 to 1989, and observations were continued. Soil nematode was not found in C. tora mono-cropping plot from mid growing season of C. tora while many nematodes were found in soybean mono-cropping plot in 1986. A few nematodes were found for 3 years in soybean field after one season cultivation of C. tora in 1986. Number of nematodes was lower in soybean-C. tora companion and inter-cropping plots compared with soybean mono-cropping, and was also lower for 3 years in soybean field after one season companion and inter-cropping culture in 1986 compared with continuous soybean cultivation plot. No root nodule was formed on C. tora root, but number of root nodules of soybean plant grown in C. tora companion and inter-cropping plots was not different with soybean mono-cropping plot. Number of pods. number of seeds and seed weight per soybean plant grown in C. tora companion and inter-cropping plots were almost same with soybean mono-cropping plot. When soybean was cultivated in field after one season C. tora mono, companion or inter-cropping, pod and seed number, and seed weight per plant were higher than continuous soybean cultivation field.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2011.11a
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• pp.16-18
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• 2011

Evaluation of climate change on the rice productivity was conducted using crop growth simulation model, where Odae, Hwaseong, Ilpum were used as a representative cultivar of early, medium, and medium-late rice maturity type, respectively, and climate change scenario 'A1B' was applied to weather data for future climate change at 57sites. When cropping season was fixed, rice yield decreased by 4~35% as climate change which was caused by poor filled grain ratio with high temperature and low irradiation during grain-filling. When cropping season was changed, rice yield decreased by only 0~5% as climate change which was caused poor filled grain ratio with low irradiation during grain-filling period. However, this irradiation decline was less than when cropping season was fixed. Therefore, we need to develop rice cultivars resistant to low irradiation which can maintain high filled grain ratio under poor irradiation condition, and late maturity rice cultivars whose growing period is longer than the present medium-late maturity type.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.47-47
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• 2017

Rice cropping in Cambodia was commonly classified into 4 types: rainfed rice, irrigated rice, floating rice and recession rice. The cropping type has been selected by farmers depended on water condition in each locations. However, recent technological and social change enforce famers to adapt new management of rice cropping. This study aimed to clarify the change in rice cropping and problems for future. Interviews to farmers has been conducted several times in Pursat province, which is one of the major rice production provinces in Cambodia. The last interview was conducted in March 2017, and focused on change in rice cropping for 10 years. Statistical data was obtained from Provincial Ministry of Agriculture in Pursat. The satellite data (LAI products derived from MODIS) was used to quantify change in cropping pattern. The statistical data shows increase in production and yield of rice, dry season rice and so on.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.335-340
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• 2016

Soil organic carbon plays an important role on soil physico-chemical properties and crop yields in paddy soil. However, there is little information on the soil organic carbon under different forage cultivation during winter season in rice paddy. In this study, we investigated the soil organic carbon and physico-chemical properties in 87 fields of paddy soil cultivated with Barley, rye, and Italian ryegrass (IRG) as animal feedstock during winter season. Organic carbon was 12.9, 14.3, and $16.9g\;C\;kg^{-1}$ in soil with barley, rye, and IRG cultivation, respectively. Among rice-forage cultivation systems, the rice+IRG cropping system was 19.5% higher than in the mono-rice cultivation. Bulk density ranged from 1.17 to $1.28g\;cm^{-3}$ irrespective of cropping systems, and had strongly negative correlation with the soil organic carbon in the rice+IRG cropping system. Carbon storage in rice+IRG cropping systems was average $29.6Mg\;ha^{-1}$ at 15 cm of soil depth, which was 20.4 and 10.3% higher than those of barley and rye cultivation. Increasing carbon storage in paddy soil contributed to the fertility for following rice cultivation. This results indicated that IRG cultivation during winter season could be an alternative and promising way to enhance soil organic carbon content and fertility of paddy soil.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.3
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• pp.107-112
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• 2018

In this study, we conducted to analyze and quantify the amount of nitrogen supply into the rice paddies from the rainfall during cropping and non-crop periods. Rainfall monitoring conducted 85 times from June 2015 to December 2017. Nitrogen supply of cropping season ranged from 5.37 to 7.70 kg/ha, while non-cropping season were supplied from 3.97 to 4.42 kg/ha. The supply of T-N in the crop period was more than 60% of the total supply. And as a result of analyzing the correlation between the characteristics of rainfall and the supply amount, nitrogen concentrations in rainfall were decreased with increasing rainfall, but the supply amount was increased. Therefore, efforts should be made to increase the rainfall utilization and to increase the nitrogen supply of crops by increasing rainfall storage through drainage management.

• Korean Journal of Plant Resources
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• v.25 no.6
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• pp.700-706
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• 2012

Influences of different seeding dates on growth, seed yield, fatty acid composition and oil content were investigated in flax plants for two years. The results indicated that plant height in early seeding date was higher than that of delayed seeding dates during first season. Furthermore, seeding date also significantly affected the ripened seed rate and the rate increased with the delay in seeding date in first season. Seed yield in the first crop season was significantly higher than the second crop season. Palmitic acid showed variation in different seeding dates. Contrarily, stearic acid was stable and did not changed by different seeding dates. Linolenic acid was found in highest amount in all seeding dates consecutively in two cropping years. Highest oil content was recovered from the seeds of flax sown at 29 Apr. and May 9 in first and second cropping year respectively.