• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.194-204
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• 2020

Cultivar parameters, which are key inputs to a crop growth model, have been estimated using observation data in good quality. Observation data with high quality often require considerable labor and cost, which makes it challenging to gather a large quantity of data for calibration of cultivar parameters. Alternatively, data in sufficient quantity can be collected from the reports on the evaluation of cultivars by region although these data are of questionable quality. The objective of our study was to assess the quality of crop and management data available from the reports on the regional adaptation trials for rice cultivars. We also aimed to propose the measures for improvement of the data quality, which would aid reliable estimation of cultivar parameters. DatasetRanker, which is the tool designed for quantitative assessment of the data for parameter calibration, was used to evaluate the quality of the data available from the regional adaptation trials. It was found that these data for rice cultivars were classified into the Silver class, which could be used for validation or calibration of key cultivar parameters. However, those regional adaptation trial data would fall short of the quality for model improvement. Additional information on management, e.g., harvest and irrigation management, can increase the quantitative quality by 10% with the minimum effort and cost. The quality of the data can also be improved through measurements of initial conditions for crop growth simulations such as soil moisture and nutrients. In addition, crop model improvement can be facilitated using crop growth data in time series, which merits further studies on development of approaches for non-destructive methods to monitor the crop growth.

• Proceedings of the Korean Society of Crop Science Conference
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• 2002.05a
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• pp.53-57
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• 2002

Quality evaluation must be more developed in order to offer the sufficient information for producer, distribution centers buyer, consumer. There are many parameters which influence the rice quality and cooked rice. It is difficult to evaluate the quality of rice and cooked rice by only some parameters. In the case of rice quality evaluation in Korea, physicochemical inspection is performed by examining the minimum and maximum limits of brown rice recovery, moisture content, damaged kernel, and colored kernel as inspection standard. Marketing standard of rice defines the limits of perfect, white core and belly, colored, damaged kernels, and broken rice, classifying into special, excellent, and normal grades. As a research direction for the development of rice quality evaluation, establishment as parts of technical field, must be further developed as follows : more detailed measure of characters, search of unknown taste-related components, creation and grade classification of quality evaluation factors at each management stages of treatment after harvesting, evaluation as food material as well as cooking rice, method development for simple evaluation and establishment of equation for palatability. In the side of policy, the following concerns must be conducted: price discrimination in conformity to rice cultivar and grade under the basis of qualify evaluation method developed, fixation of head rice branding, and introduction of low temperature circulation.

• Journal of Distribution Science
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• v.14 no.11
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• pp.29-36
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• 2016

Purpose - Intense debate is occurring over support for farmers in Korea, specifically on the justification, policy design, and equality issues of the farm support programs. Given this debate, a new type of farm program in the US, a market flexible revenue program(the Average Crop Revenue Election, ACRE), is examined. ACRE stands in contrast to traditional programs that tie payments to price and have parameters that are fixed or change only infrequently. Research design, data, and methodology - Based on the ACRE program formulas, the potential payments are estimated by crop year, program crop and geographical area using the FSA acreage and payment rate data. Results - If all US farm program acres were in ACRE over the 2009-2013 crop years, payments would have totaled $7.95 billion or 1.2 percent of average market receipts for US crops. Enacting ACRE as a revenue program instead of a similarly-structured price-only program increased payments by $1.75 billion or 28 percent. Conclusions - Potential payments by ACRE largely reflected the distribution of the value of production across the program crops eligible for ACRE as well as across state geographical areas. If program parameters can be made acceptable and if data availability issues can be addressed, market flexible revenue programs offer a farm policy option that can address many of the concerns that have arisen over farm policy in Korea.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.95-100
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• 2006

Brown rice with a giant embryo (GE) was observed on the quality parameters of the enlargement of embryo, nutritional components, and physical properties, in comparison to normal embryo brown rice (NE). Also, the effects of germination on the quality parameters were examined. GE embryo was approximately 2.68 times larger than of NE rice. Total free sugars were significantly higher in GE rice (71.96 vs. 41.17 mg/100 g), and germinated rice increased in fructose, but decreased in sucrose and maltose. No significant difference in mineral contents was found in GE and NE rice and their germinated rice, whereas a significant increment was observed on reducing sugars and gamma-amino butyric acid (GABA) contents in GE rice. The lower water absorption index (WAI) of GE rice resulted in relatively lower pasting viscosity, whereas the increased WSI in germinated rice might be attributable to the significant increment of soluble components in GE rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.604-608
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• 1997

Ten selected soybean genotypes, consisting of nine from a pedigree breeding programme and one recommended variety, were evaluated in nine different locations and over two years for stability of yield performance. Variance component analysis revealed that soybean regional yield trials should be performed at more locations rather than in more years. Five stability parameters, which were coefficient of variability, regression coefficient, deviation parameter, variance component for genotype$\times$environment interaction, and ecovalence, were employed in the evaluation. Significant genotype$\times$environment interaction was present with respect to soybean yield. The highest average yield over nine locations and two years was shown in Suwon 145, which was considered to be stable in all stability statistics. In rank correlation among stability parameters, there were highly significant correlations among stability parameters derived from three Eberhart and Russell's, Plaisted's, and Wricke's methods. Due to the different ranking of genotypes by different stability parameters, a comprehensive method should be employed to identify the promising genotype as well as to characterize the relationship between genotype and environment.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.285-295
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• 2006

Korean water quality standards for the protection of agricultural water uses were originally derived based on management of public water resource. They were not prepared to protect crop plants from contaminants, and therefore required water parameters in agricultural uses were excluded in current water quality standards. Korean water standards in river and lake have five levels, and level IV is correspondent to agricultural water uses. Currently, there is no Korean guidelines to protect crop plants from contaminants contained in agricultural water. In Canada, agricultural water guidelines are provided to protect crops from contaminants. In this study, agricultural water quality standards in Korea were compared with them in developed countries to evaluate the adequacy of Korean water quality standards for the protection of agricultural water uses. Additional water quality parameters in agricultural uses were also proposed. Suggested parameters include electric conductivity, sodium, chloride, boron, copper, iron, zinc, and microbiological quality, They are the required parameters to protect crop plants as well as human health. Current water quality standards in agricultural uses was not considered to be appropriate in terms of crop protection. Additional water parameters should be included in agricultural water quality standards.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.45-45
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• 2017

On-site monitoring of vegetable growth parameters, such as leaf length, leaf area, and fresh weight, in an agricultural field can provide useful information for farmers to establish farm management strategies suitable for optimum production of vegetables. Unmanned Aerial Vehicles (UAVs) are currently gaining a growing interest for agricultural applications. This study reports on validation testing of previously developed vegetable growth estimation models based on UAV-based RGB images for white radish and Chinese cabbage. Specific objective was to investigate the potential of the UAV-based RGB camera system for effectively quantifying temporal and spatial variability in the growth status of white radish and Chinese cabbage in a field. RGB images were acquired based on an automated flight mission with a multi-rotor UAV equipped with a low-cost RGB camera while automatically tracking on a predefined path. The acquired images were initially geo-located based on the log data of flight information saved into the UAV, and then mosaicked using a commerical image processing software. Otsu threshold-based crop coverage and DSM-based crop height were used as two predictor variables of the previously developed multiple linear regression models to estimate growth parameters of vegetables. The predictive capabilities of the UAV sensing system for estimating the growth parameters of the two vegetables were evaluated quantitatively by comparing to ground truth data. There were highly linear relationships between the actual and estimated leaf lengths, widths, and fresh weights, showing coefficients of determination up to 0.7. However, there were differences in slope between the ground truth and estimated values lower than 0.5, thereby requiring the use of a site-specific normalization method.

• Korean Journal of Medicinal Crop Science
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• v.28 no.6
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• pp.412-420
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• 2020

Background: Measurement of chlorophyll fluorescence (CF) is useful for detection the ability of plants to tolerate environmental stresses such as drought, and excessive sunlight. Cnidium officinale Makino is highly sensitive to water stress and excessive sunlight. In this study, we evaluated the effect of soil water and shade treatment on the photosynthesis and leaf temperature change of C. officinale. Methods and Results: C. officinale was cultivated under uniform irrigation for 1 week drought stress (no watering) for 6 days. A significant decrease in CF was observed on the 5th day of withholding water (approximately 6% of soil water content) regardless of shading. Notably, the Rfd_lss parameter (CF decrease rates) with and without shade treatment was reduced by 73.1% and 56.5% respectively, at 6 days compared with those at the initial stage (0 day). The patterns of the degree of CF parameters corresponded to those of the soil water content and difference between leaf temperature (Ts) and air temperature (Ta). Meanwhile, CF parameters recovered to the 3 - 4 days levels after re-watering, while the soil water potential was completely restored. The suitable soil water content for C. officinale optimal growth was between -5 kPa and -10 kPa in this experiment. Conclusions: Lack of soil water in the cultivation of C. officinale, even with shading, decreased latent heat cooling through transpiration. As a result, heat dissipation declined, and the plant was subjected to drought stress. Soil water content plays a major role in photosynthesis and leaf temperature in C. officinale.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.1
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• pp.42-54
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• 2019

Crop models depend on a large number of input parameters including the cultivar parameters that represent the genetic characteristics of a given cultivar. The cultivar parameters have been estimated using high quality data for crop growth, which require considerable costs and efforts. The objective of this study was to examine the feasibility of using low quality data for the parameter estimation. In the present study, the cultivar parameters for cv. Shindongjin were estimated using the data obtained from the report of new cultivars development and research from 2005 to 2016. The root mean square errors (RMSE) of the heading dates were less than 3 days when the parameters associated with phenology were estimated. In contrast, the coefficient of determination for yield tended to be less than 0.1. The large errors incurred by the fact that no growth data collected over a season was used for parameter estimation. This suggests that detailed observation data needs to be prepared for parameter calibration, which would be aided by remote sensing approaches. The occurrence of natural disasters during a growing season has to be considered because crop models cannot take into account the effects of those events. Still, our results provide a reasonable range for the parameters, which could be used to set the boundary of a given parameter for cultivars similar to cv. Shindongjin in further studies.

• Proceedings of the Korean Society of Crop Science Conference
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• 2004.04a
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• pp.104-105
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• 2004

[ $\bigcirc$ ] In the phenology model of ORYZA2000, the effect of photoperiod on the developmental rate was a little ignored because most crop parameters were measured with IRRI varieties which are insensitive to photoperiod, therefore it is very difficult to apply this phenology model directly to Korean varieties which are usually sensitive to photoperiod. $\bigcirc$ After introducing PPFAC and PPSE to improve the phenology model, the precision of heading date prediction was improved but not satisfied. $\bigcirc$ In the growth simulation using data from several regions, yield tended to be overestimated under high nitrogen applicated condition. $\bigcirc$ The precision of yield was much improved by introducing nitrogen use efficiency, but still different between regions because of different soil fertility or property of irrigation water between regions