• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.926-936
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• 1996

Field hulling of high-moisture paddy followed by brown rice drying offers many advantages over the present paddy harvesting and drying offers many advantages over the present paddy harvesting and drying system. We did a preliminary study of the parameters for efficient hulling of high-moisture paddy using the IRRI Centrifugal Huller and two India rice varieties. Hulling capacity , hulling efficiency , brown rice recovery and percent whole bown rice were generally best at the impeller peripheral speed of 44m/s. A second pass through the huller increased hulling capacity , brown rice revery and hulling efficiency, but reduced percent whole brown rice. To solve this , we recommed separation of paddy after hulling and aspiration such that only unhulled and partially -hulled grains will be fed back to the huller. Paddy at even 23% m.c. could be effectively hulled by the impeller-type huller , but the results were generally better at 14 to 17% m.c. Only in percent whole brown rice did the 17 to 23% m.c. range performed better than that of 14% m.c. Difference invarietal response to hulling was observed.

• Journal of Biosystems Engineering
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• v.33 no.5
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• pp.362-369
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• 2008

There is developing interest in precision agriculture in Korea, despite the fact that typical Korean fields are less than 1 ha in size. Describing within-field variability in typical Korean production settings is a fundamental first step toward determining the size of management zones and the inter-relationships between limiting factors, for establishment of site-specific management strategies. Measurements of rice (Oriza Sativa L) yield, chlorophyll content, and soil properties were obtained in a small (100-m by 30-m) Korean rice paddy field. Yield data were manually collected on 10-m by 5-m grids (180 samples with 3 samples in each of 60 grid cells) and chlorophyll content was measured using a Minolta SPAD 502 in 2-m by 2-m grids. Soil samples were collected at 275 points to compare results from sampling at different scales. Ten soil properties important for rice production in Korea were determined through laboratory analyses. Variogram analysis and point kriging with and without median polishing were conducted to determine the variability of the measured parameters. Influence of variogram model selection and other parameters on the interpretation of the data was investigated. For many of the data, maximum values were greater than double the minimum values, indicating considerable spatial variability in the small paddy field, and large-scale spatial trends were present. When variograms were fit to the original data, the limits of spatial dependency for rice yield and SP AD reading were 11.5 m and 6.5 m, respectively, and after detrending the limits were reduced to 7.4 m and 3.9 m. The range of spatial dependency for soil properties was variable, with several having ranges as short as 2 m and others having ranges greater than 30 m. Kriged maps of the variables clearly showed the presence of both large-scale (trend) variability and small-scale variability in this small field where it would be reasonable to expect uniformity. These findings indicate the potential for applying the principles and technology of precision agriculture for Korean paddy fields. Additional research is needed to confirm the results with data from other fields and crops.d similar tendency with the result for the frequency less than 20 Hz, but the width of change was reduced highly.

• The Journal of Korea Robotics Society
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• v.11 no.1
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• pp.1-8
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• 2016

In this paper, we propose a new algorithm of the guidance line extraction for autonomous agricultural robot based on vision camera in paddy field. It is the important process for guidance line extraction which finds the central point or area of rice row. We are trying to use the central region data of crop that the direction of rice leaves have convergence to central area of rice row in order to improve accuracy of the guidance line. The guidance line is extracted from the intersection points of extended virtual lines using the modified robust regression. The extended virtual lines are represented as the extended line from each segmented straight line created on the edges of the rice plants in the image using the Hough transform. We also have verified an accuracy of the proposed algorithm by experiments in the real wet paddy.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1002-1004
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• 2003

A ground-based, C-band full polarimetric mobile Scatterometer system has been developed in Malaysia with collaboration between Malaysian Centre for Remote Sensing (MACRES) and Multimedia University (MMU). The main purpose of this system is to measure and monitor backscattering coefficient, ${\sigma }^0$, for earth terrain such as paddy fields, forest and soil surfaces. This paper describes the preliminary results on radar backscatter measurement from paddy field using the mobile C-band Scatterometer system. The measurement campaign was conducted at Sungai Burung area in April 2003. Real time data were collected using four polarization modes (HH, HV, VV and VH), at various incidence angles ranging from 0$^0$ to 60$^0$. The measurement data show consistent results as compared to other reports, which verify the capability of this Scatterometer system as a useful tool for remote sensing.

• KCID journal
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• v.17 no.2
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• pp.105-114
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• 2010

Tidal land reclamation provided water resources and land for agriculture and contributed stable crop production. However, climate change by global warming disrupts the hydrologic circulatory system of the earth resulting in sea level rise and more frequent flood for reclaimed arable land. Recently, Suyu reclaimed paddy field in Jindo-gun experienced prolonged inundation after heavy rainfall and there is a growing risk of flood damage. Onsite survey and flood analysis using GATE_Pro model of Korea Rural Corporation were conducted to investigate causes of flooding. To perform the analysis, input data such as inflow hydrograph, the lowest elevation of paddy field, neap tide level, management level of Gunnae estuary lake at the time of the flood were collected. Flood analysis confirmed that current drainage facilities are not enough to prevent 20year return period flood. The result of analysis showed flooding more than 24hours. Therefore, flood mitigation alternatives such as sluice gate expansion, installation drainage pumping station, refill paddy land, and catch canal were studied. Replacing drainage culvert of Suyu dike to sluice gate and installing drainage pumping station at the Gunne lake were identified as an effective flood control measures. Furthermore, TM/TC (SCADA) system and expert for gate management are required for the better management of drainage for estuary dam and flood mitigation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.3
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• pp.163-170
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• 2001

The objective of this study was to evaluate land cover classification of PyeongTaeg area by Landsat Thematic Mapper Data June, 1997. This study was also to make more correct reference data using DGPS, aerophoto, and topographical chart etc.. The result of the area of paddy and upland were estimated 4,949 $\textrm{km}^2$ and 16,157 $\textrm{km}^2$, respectively. Correctness of estimation by using DGPS, aerophoto, topographical chart were shown over 90% correct in case of rice paddy field, water, and sea, while upland, vinyl house, forest, grassland, village were shown low correctness. Total average accuracy was shown to be 85.8%. Correctness of paddy field showed high value of 92%, showing that use of remote sensing data was proved to be effective methods to estimate spatial distribution and cultivation status of paddy field. Classification result of sea, water area, downtown had higher correctness, while upland, vinyl-house, grassland were proved to be relatively low correctness because of it's small area and mixed distribution.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.319-325
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• 2010

The purpose of this study is to investigate the soil compositions, methane production, the number of methanogens, and the community structure of methanogens in rice paddy soils and dry field farming soils in the summer and autumn seasons. As a result of the analysis of soil compositions, any regular tendency to increase or decrease has not been found in most soil samples due to the change of seasons. It has also been found that more methanogens exist in the rice paddy soil that utilize organic farming practices and emptiness farming practices than in the dry field farming soil. The fewer numbers of methanogens utilizing the acetate have been found than those of the methanogens utilizing the hydrogen or the formate. In an experiment of methane production, the methanes increased for two weeks when the acetate was added, but they continued to increase for seven weeks more when the formate and the hydrogen were added. In the phylogenetic analysis using the mcrA gene, the methanogens had diverse clusters in the rice paddy soil, whereas the methanogens were concentrated only in a few clusters in the dry field farming soil.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.5
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• pp.127-135
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• 2002

Water quality samples were taken for every two hours whenever runoff occurred by rainfall to investigate concentration variations of T-N, T-P and SS during runoff process from a paddy field. The difference between the highest concentration in a runoff event and flow weighted mean concentration for T-N, T-P, SS placed between 3.07∼40.16%, 11.44∼60.80%, and 15.11∼64.5%, respectively. The difference between the lowest concentration in event and event mean concentration for T-N, T-P, SS ranged between -7.24∼-31.84%, -11.59∼-47.86%, and -5.21∼-36.20%, respectively. The relationship between runoff and mass load was derived for each storm event using observed data. The relationship between runoff and mass load showed linear relationship regardless of water quality constituents and rainfall amount. The results suggested that relationship between T-N and T-P loads and runoff should be prepared separately in considering of fertilization effect and seasonal conditions. The relationship between SS and runoff should be made to reflect seasonal conditions and tillage effect.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.2
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• pp.11-16
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• 2008

The effects of water and pesticide management practices on ponded water pesticide concentrations in a paddy plot were analysed using the RICEWQ model. The molinate which is a herbicide widely used in rice culture, and frequently detected in paddy environment was selected. In a previous study, the RICEWQ model was successfully calibrated with field data obtained from a paddy plot in Daegu. The calibrated model was run using water and pesticide management scenarios with a set of measured meteorological data for 1997-2006 in Daegu. For all three ponded water depths with the label rate application, the amount of molinate dissipated in ponded water and volatilized accounted for more than 70%, and the runoff losses were less than 9%. The molinate losses through drainage in the very shallow ponded depth showed 40% less than that in deep ponded depth. Comparing with the deep and shallow ponded depth, the very shallow depth was the best with regards to the reduction of molinate runoff losses. Simulations with different pesticide application rates, label rate and double label rate, showed molinate concentrations in the ponded water increased linearly with the application rate increase.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1943-1947
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• 2007

The objective of this research was to find a direct and indirect method to estimate land surface temperature (LST) efficiently, using Landsat images and in-situ measurement. Agricultural fields including paddy fields have long been known to have multi-functions beneficial to the environment and ecology of the urban surrounding areas. Among these functions, the ambient temperature cooling (ATC) effect are widely acknowledged. However, quantitative and regional assessment of such effect has not had many investigations. Thermal remote sensing has been used over urban areas to assess ATC effect, to perform land cover classifications and as input for models of urban surface atmosphere exchange. Here, we review the use of thermal remote sensing in the study of paddy fields and urban climates, focusing primarily on the ATC effect. Landsat satellite images were used to determine the surface temperatures of different land cover types of a $441km^2$ study area in Cheongju, Korea. The results show that the ATC are a function of paddy area percentage in Landsat pixels. Pixels with higher paddy area percentage have more significant cooling effect.