• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.1
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• pp.27-33
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• 2023

Several domestically consumed sweetpotato derivatives, such as sweetpotato starch for processing raw materials, frozen and refrigerated paste, and powder are dependent on imports. This study was conducted to examine the suitability of sweetpotato cultivars of twelve varieties (powdery-type and viscous type) cultivated in paddy fields, for use in starch, chips, dried products, and beverages. The two-year average yield results of the four cultivars suitable for starch (in order of highest to lowest yield) was as follows: Gogeonmi (4,018 kg/10a); Daeyumi (3,615 kg/10a); Jinhongmi (3,426 kg/10a); Singeonmi (2,837 kg/10a). The starch content was 20.2%, 18.2%, 21.2%, and 20.6% in Daeyumi, Gogeonmi, Singeonmi, and Jinghongmi, respectively. The total amount of starch was higher in Daeyumi (730 kg/10a) and Gogeonmi (731 kg/10a) than that in Singeonmi and Jinghongmi. The yield of Pungwonmi and Shinjami were 4,443 and 3,602 kg/10a, respectively. Powdery-type sweetpotatoes (Daeyumi and Gogeonmi) showed the low decay rates of all cultivars (0.8 and 0%, respectively). The yield of the storage root formation and storage root swelling stages by water-logging treatment decreased by 16.5% and 15.4% for Pungwonmi, and by 17.2% and 10.0% for Shinjami. Drainage management of paddy fields is necessary to reduce the damage caused by water-logging. Our results suggest that cultivation of sweetpotato varieties suitable for processing raw materials in paddy fields will enable stable yields of sweetpotato with a high starch content.

• Applied Biological Chemistry
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• v.32 no.2
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• pp.104-108
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• 1989

A 2.5 ton scale of solar energy concentration blast-grain circulation dryer (SECD) was developed in order to shorten the drying time without damaged paddy. Comparative experiments were carried out on performance, drying efficiency, consistency in moisture content, milling recovery, grade of milled rice, and energy requirement and cost against all that of in-bin drying and storage (IBDS) method. The experiments were performed using mixture of several rice varieties of Tongil type(Japonica-Indica breeding type) under the autumn weather in Korea. The circulating air temperature inside SECD was $4{\sim}5^{\circ}C$ higher than that of IBDS. The moisture content of the paddy during the drying period in SECD was uniform while substantially varied in upper, middle or bottom layer in IBDS. By SECD, 24% initial moisture content of paddy was reduced to 15% after only 3 days of drying as compared to 14 days at IBDS. The percentage of cracked kernels in upper, middle and bottom layers in IBDS was 6, 6 and 12%, respectively, whereas 7% in all layers in SECD. Both types of dryers did not significantly affect the milling recovery of dried paddy and grade of milled rice. Energy requirement of SECD(28.8Kw/2.5ton) for paddy drying was much less than that of IBDS(108Kw/2.5ton).

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1194-1202
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• 2012

Remotely sensed satellite images can be applied to monitor and obtain land surface information on inaccessible areas. We classified paddy field area in North Korea based on on-screen digitization with visual interpretation using 291 RapidEye satellite images covering the whole country. Criteria for paddy field classification based on RapidEye imagery acquired at different time of rice growth period was defined. Darker colored fields with regular shape in the images with false color composite from early May to late June were detected as rice fields. From early July to late September, it was hard to discriminate rice canopy from other type of vegetation including upland crops, grass, and forest in the image. Regular form of readjusted rice field in the plains and uniform texture when compared with surrounding vegetation. Paddy fields classified from RapidEye imagery were mapped and the areas were calculated by administrative district, province or city. Sixty six percent of paddy fields ($3,521km^2$) were distributed in the west coastal regions including Pyeongannam-do, Pyeonganbuk-do, and Hwanghaenam-do. The paddy field areas classified from RapidEye images showed less than 1% of difference from the paddy field areas of North Korea reported by FAO/WFP (Food and Agriculture Organization/World Food Programme).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.4
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• pp.214-222
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• 1998

These experiments were conducted to investigate water uptake, electrical conductivity, germination percentage, seedling growth, and seedling establishment rate in direct seeding cultivation of rice. The rice seeds of six japonica type varieties were coated with 12 kinds of polymers in a standard concentration of 0.2% using seed coating machine. The water absorption of the polymer-coated seeds under saturation conditions was not different among varieties, and was the highest in kulcel, maltrin, and waterlock on the polymer-coated seeds. The electrical conductivity with waterlock (55.0 $\mu scm^{-1}g^{-1}$) was higher than the control plot (45.6 $\mu scm^{-1}g^{-1}$) and other treatments. The germination of the polymer-coated seeds was 95.9% at control plot, 92.7% at low temperature and 35.7% at high temperature. The total dry weight of seed decreased in the order of low temperature, control plot, and high temperature, and was effective in pvp (polyvinyl pyrrolidone), opadry, and sacrust. The seedling establishment rate in direct seeding cultivation ranged from 74.9 to 81.0% in flooded paddy surface, and ranged from 64.7 to 76.6% in dry paddy. In both cases, it decreased in the order of early, medium and medium-late varieties, but was enhanced in daran 8600, sepirect, and sacrust. According to this study the recommended polymers for direct seeding cultivation of rice are daran 8600, sepirect, and sacrust.

• Korean Journal of Environmental Agriculture
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• v.25 no.1
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• pp.71-76
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• 2006

Environment friendly agriculture is nowadays a major fiend to sustain balanced agricultural ecosystem, keeping its productivity. This study was conducted to determine the optimum levels of nitrogen (N) application for improving rice productivity and reducing N loss through N application based on soil diagnosis. four levels of N were applied with 0, 50, 100 and 150% of recommended levels by soil testing in 4 different paddy soils (i.e. normal, sandy, ill-drained and immature soils). Across N treatments, the greatest grain yield was observed in sandy soil and the lowest in ill-drained soil. The grain yield tended to decrease with increasing N application from 50% to 150% of recommended levels, except ill-drained soil. To ensure maximum yield the optimum levels of N application were estimated at 120 kg, 153 kg and 173 kg $ha^{-1}$ in normal, immature and sandy soil, respectively.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.324-327
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• 2008

Microwave remote sensing has great potential, especially in monsoon Asia, since optical observations are often hampered by cloudy conditions. The radar backscattering characteristics of rice crop were investigated with a ground-based automatic scatterometer system. The system was installed inside a shelter in an experimental paddy field at the National Institute of Agricultural Science and Technology (NIAST) before transplanting. The rice cultivar was a kind of Japonica type, called Chuchung. The scatterometer system consists of X-band antennas, HP8720D vector network analyzer, RF cables, and a personal computer that controls frequency, polarization and data storage. This system automatically measures fully-polarimatric backscattering coefficients of rice crop every 10 minutes, accompanied by a digital camera that takes pictures in a fixed position with the same interval. The backscattering coefficients were calculated by applying a radar equation. Plant variables, such as leaf area index (LAI), biomass, plant height and weather conditions were measured periodically throughout the rice growth season. We have performed polarimetric decomposition of paddy data such as single, double and volume scattering to extract the scattering information effectively. We investigated the relationships between backscattering coefficients and the plant variables.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.633-636
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• 2007

The objective of this study is to measure backscattering coefficients of paddy rice using L, C, X-bands scatterometer system during a rice growth period. The measurement was conducted at an experimental field located in National Institute of Agricultural Science and Technology (NIAST), Suwon, Korea. The rice cultivar was a kind of Japonica type, called Chuchung. The scatterometer system consists of dual-polarimetric square horn antennas, HP8720D vector network analyzer (20MHz ${\sim}$ 20GHz), RF cables, and a personal computer that controls frequency, polarization and data storage. The scatterometer system is calibrated using a calibration kit (3.5mm, 85052D). The backscattering coefficients were calculated by applying radar equation for the measured at incidence angles between $20^{\circ}$ and $60^{\circ}$ for four polarization (HR, VV, HV, VH), respectively, and compared with rice growth data such as plant height, stem number, biomass, dry weight and LAI that were collected at time of each scatterometer measurement simultaneously.

• Applied Biological Chemistry
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• v.12
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• pp.13-17
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• 1969

The fractions of protein, albumin, globulin, oryzenin, and prolamine extracted from 20 varieties of rice were determined, which include upland and paddy rice with both waxy and nonwaxy types. The protein content is higher in the waxy type and especially in upland rice. The content of oryzenin and albumin were likewise higher in the waxy and upland types. The results were discussed in the view point of nutrition.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.1
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• pp.49-54
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• 1995

Three types of floating-type automatic inlet were developed for the purpose of reduc- ing farmer's working hours required for water management and saving irrigation water. The point of automation is to use a float within the inlet which is floated and sinked by the ponding depth of paddy field, Thus opens and closes the control gate of irrigation. Suitability of each inlet may depend on production cost, applicability to paddy field condi- tions, and feasibility to farmers, etc. The first model was composed of three parts : chamber for irrigation control gate, chamber for float controlled by ponding depth, and connection bar between the two parts. It was designed to open and close the control gate gradually as the ponding depth drops and rises to a certain level. The second model was designed to improve the weak point of the first model which is the imperfect-closing of gate when it approaches to the end of ir- rigation. A switch-spring was equipped above the connection bar for perfect opening and closing of gate when the ponding depth reaches to a certain level. The third model was designed by combining the two chambers, that is, cut in halves the inlet volume of the above two models. Magnets were equipped above the float for perfect opening and closing gate. The functional experiment for three developed inlets was successfully carried out and the rating curves were derived.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.2
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• pp.146-150
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• 1995

The yield performance and nutrient quality of barley for pellets making from whole crop material were discussed during 1993-1994. Barley (cv. Olbori) was grown on paddy land after rice cutivation and was harvested at early stage of physiological maturity. A column type of whole crop pellets was produced by 1.5cm diameter and 2.5cm height. Barley war evaluated as a suitable materials for whole crop pellet making. Barley produced higher yield and better qualitative roughage in the utilization of pellet making than in the silage making. Dry matter yields were obtained 12.02 MTha in pellet making and 11.70 MT/ha in silage making. Net energy value of barley pellet were 6.54 MJ in net energy lactation and 635 SV in starch equivalent net energy. Feeding of barley pellet improved milk production of daily cattle Daily milk yields per head were 25.1 liter in silage feeding and 25.9 liter in pellet feeding. Production cost of pellets and silages made from whole crop barley were 169.07 won/kg and 124.15 won/kg dry matter, respectively.