• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.555-563
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• 2016

Uniformity and leveled distributions of soil chemicals across paddy fields are critical to manage optimal crop yields, reduce environmental risks and efficiently use water in rice cultivation. In this study, an investigation of spatial distributions on soil chemical properties was conducted to evaluate the effect of land leveling on mitigation of soil chemical property heterogeneity from a remodeled paddy field. The spatial variabilities of chemical properties were analyzed by geostatistical analyses; semivariograms and kriged simulations. The soil samples were taken from a 1 ha paddy field before and after land leveling with sufficient water. The study site was located at Bon-ri site of Dalseong and river sediments were dredged from Nakdong river basins. The sediments were buried into the paddy field after 50 cm of top soils at the paddy field were removed. The top soils were recovered after the sediments were piled up. In order to obtain the most accurate spatial field information, the soil samples were taken at every 5 m by 5 m grid point and total number of samples was 100 before and after land leveling with sufficient water. Soil pH increased from 6.59 to 6.85. Geostatistical analyses showed that chemical distributions had a high spatial dependence within a paddy field. The parameters of semivariogram analysis showed similar trends across the properties except pH comparing results from before and after land leveling. These properties had smaller "sill" values and greater "range" values after land leveling than ones from before land leveling. These results can be interpreted as land leveling induced more homogeneous distributions of soil chemical properties. The homogeneous distributions were confirmed by kriged simulations and distribution maps. As a conclusion, land leveling with sufficient water may induce better managements of fertilizer and water use in rice cultivation at disturbed paddy fields.

• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.749-760
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• 2018

In Korea, the largest agricultural lands are paddy fields which have poor infiltration and drainage properties. Recently, the Korean government has pursued cultivating upland crops in paddy fields to reduce overproduced rice in Korea. For this policy to succeed, it is critical to understand the topographic information of paddy fields and its effects on upland crops cultivated in the soils of paddy fields. The objective of this study was to characterize the growth properties of sesame and perilla from paddy fields with three soil topographic features and soil water effects which were induced by the topographic features of the sesame and perilla. The crops were planted in paddy fields located in Miryang, Gyeongnam with different topographies: mountain foot slope, local valley and alluvial plain. Soil water contents and groundwater levels were measured every hour during the growing season. The paddy field of the mountain foot slope was significantly effective in alleviating wet injury for the sesame and perilla in the paddy fields. The paddy field of the mountain foot slope had a decreased average soil water content and groundwater level during cultivation. Stress day index (SDI) from the alluvial plain paddy field had the greatest values from both crops and the smallest from the ones from the paddy field of the mountain foot slope. This result means that sesame and perilla had the smallest stress from the soil water content of the paddy field on the mountain foot slope and the greatest stress from the soil water content of the alluvial plain. It is important to consider the topography of paddy fields to reduce wet injury and to increase crop yields.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.343-343
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• 2017

This study was conducted to investigate cropping system using paddy field in 152 cities and counties of Korea. Out of the 152 cities and counties, 106 regions responded(70%). The number of cultivated crops in 2 and 3 cropping system using paddy field was 48 crops. Among these, 35 crops were cultivated in winter and spring, 27 crops were cultivated in summer and fall. There were 33 crops in paddy field after cultivating rice. Among these, 11 crops were cultivated in spring and 26 crops were in fall-winter. There were 44 crops in paddy field without cultivating rice. Among these, 19 crops were cultivated in spring, 27 crops were in summer, 15 crops were in fall. Total cropping systems in Korea were 138 types, 2 cropping system were 119, among them outdoor crops were 77, using facility crops were 42, and 3 cropping system crops were 19. Cropping system of Jeonbuk province was 45 types and it was the most in Korea. Cropping systems of southern area were more various than those of middle-northern area in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.309-315
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• 2004

This study was carried out to evaluate the seed quality of soybeans produced from upland and drained-paddy fields. Soybeans from drained-paddy field showed significantly higher in the 100 seeds weight and greater in the size of seed length than those from upland fields. However, there are no significant differences in seed width and thickness between upland and paddy fields. In case of Hunter's color value, the lightness (L) was significantly higher in the upland soybeans, but the a (redness) and b (yellowness) values were higher in the drained-paddy field soybeans. Seed appearance of drained-paddy field was poor than that of upland field. Soybeans produced from the drained-paddy field showed higher protein content, whereas, lipid and ash contents were higher in the upland field. Soybeans from upland field had lower contents of total amino acids compared to drained-paddy fields. No statistical differences were found in palmitic, linoleic, and linolenic, but stearic, oleic, saturated fatty acids (SFA), and unsaturated fatty acids (USFA) showed significant differences between soybean seeds from upland and drained-paddy fields. Genistein content was higher in the drained-paddy fields, while daidzein and glycitein contents were higher in the upland fields. This result suggested that the soil condition of drained-paddy field is more favorable to synthesis genistein than daidzein and glycitein.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.12-16
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• 2016

To identify the effects of straw mulching on soil physicochemical properties in reclaimed saline soil, field experiment was conducted for 3 years (2010~2012) in Saemangeum reclaimed land. Soil series of the experimental field was Munpo and soil texture was fine sandy loam. The experiment was conducted at a field with EC of $2.4dS\;m^{-1}$ (field I) and the other field with EC of $5.6dS\;m^{-1}$ (field II). Each experimental field was treated with rye straw incorporation, mulching with rye straw and control. In 2010 rye straw produced from other field was used for the experiment and in 2011~2012 rye straw cultivated at the same experimental field was used. After rye straw application, soybean was cultivated. After 3 years field experiment, by rye straw incorporation, soil salinity decreased from $2.4dS\;m^{-1}$ to $0.6dS\;m^{-1}$ at field I but increased from $5.6dS\;m^{-1}$ to $7.6dS\;m^{-1}$ at field II. By mulching with rye straw soil salinity decreased from $2.4dS\;m^{-1}$ to $0.5dS\;m^{-1}$ at field I and also decreased from $5.6dS\;m^{-1}$ to $0.5dS\;m^{-1}$ at field II. By rye straw incorporation and mulching soil organic matter increased from $2g\;kg^{-1}$ to $4g\;kg^{-1}$. At field I yields of soybean were similar between rye straw incorporation and mulching but at field II yield of soybean increased apparently by mulching with rye straw compared to rye straw incorporation and control.

• Korean Journal of Remote Sensing
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• v.40 no.1
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• pp.93-101
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• 2024

Accurate field crop classification is essential for various agricultural applications, yet existing methods face challenges due to diverse crop types and complex field conditions. This study aimed to address these issues by combining support vector machine (SVM) models with multi-seasonal unmanned aerial vehicle (UAV) images, texture information extracted from Gray Level Co-occurrence Matrix (GLCM), and RGB spectral data. Twelve high-resolution UAV image captures spanned March-October 2021, while field surveys on three dates provided ground truth data. We focused on data from August (-A), September (-S), and October (-O) images and trained four support vector classifier (SVC) models (SVC-A, SVC-S, SVC-O, SVC-AS) using visual bands and eight GLCM features. Farm maps provided by the Ministry of Agriculture, Food and Rural Affairs proved efficient for open-field crop identification and served as a reference for accuracy comparison. Our analysis showcased the significant impact of hyperparameter tuning (C and gamma) on SVM model performance, requiring careful optimization for each scenario. Importantly, we identified models exhibiting distinct high-accuracy zones, with SVC-O trained on October data achieving the highest overall and individual crop classification accuracy. This success likely stems from its ability to capture distinct texture information from mature crops.Incorporating GLCM features proved highly effective for all models,significantly boosting classification accuracy.Among these features, homogeneity, entropy, and correlation consistently demonstrated the most impactful contribution. However, balancing accuracy with computational efficiency and feature selection remains crucial for practical application. Performance analysis revealed that SVC-O achieved exceptional results in overall and individual crop classification, while soybeans and rice were consistently classified well by all models. Challenges were encountered with cabbage due to its early growth stage and low field cover density. The study demonstrates the potential of utilizing farm maps and GLCM features in conjunction with SVM models for accurate field crop classification. Careful parameter tuning and model selection based on specific scenarios are key for optimizing performance in real-world applications.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.526-531
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• 2014

This study was carried out to compare the growth characteristics and feed values of the whole crop silage rice from paddy field and reclaimed paddy field. The heading dates of tested varieties was August 8 to August 30 in the paddy field, 1~2 days later than the reclaimed paddy field's August 6 to August 29. Plant height was in the range of 105~135 cm in paddy field, and 97~126 cm in reclaimed paddy field, respectively. The plant height of Mokyang was tallest in the paddy field, but Suwon 544 was tallest in the reclaimed paddy field. The number of tiller per plant of Nokyang was largest in the paddy field. Dry matter (DM) yield of whole crop rice ranged from 15.26 to $23.24MT\;ha^{-1}$ in the paddy field and 11.94 to $18.89MT\;ha^{-1}$ in the reclaimed paddy field. The highest DM yield in both fields was attained by Mokwoo. Comparing with the paddy field, the reclaimed paddy field achieved 78~84% in the DM yield. The crude protein content of varieties was 8.5 to 11.6% in the reclaimed tidal land and 6.7~8.7% in the paddy field. Neutral detergent fiber (NDF) of varieties in both fields ranged from 31.2 to 55.5%. Suwon 544 recorded the highest NDF contents in both fields. All varieties did not show any significant difference in acidic detergent fiber (ADF) which had values ranging from 22.3 to 33.2%. Total digestion nutrient (TDN) was more than 60% overall in both fields. Regarding TDN yield, Mokwoo recorded $16.54MT\;ha^{-1}$ in reclaimed tidal land and $12.69MT\;ha^{-1}$ in the paddy field, which showed the highest figure among the varieties. These results suggest the feasibility for cultivation of the whole crop silage rice in reclaimed paddy field, which showed 80% of the yield compared to paddy field, and implied that Mokwoo would show the most excellent yield and feed value.

• The Korean Journal of Food And Nutrition
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• v.34 no.6
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• pp.584-592
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• 2021

In this study, the antioxidant activity of methanol extracts of wheat sprouts grown in wild fields and cultivated fields and harvested at various times were analyzed to compare the quality characteristics of the wheat sprouts as a function of their cultivation and harvest time, as well as for the development of functional materials. The total polyphenolic and flavonoid content, as well as antioxidant activity of the wheat extracts, were subsequently analyzed. The ABTS radical scavenging activity of the wheat extract increased from 16.97 mg TEAC/g sample on cultivation day three in cultivated field wheat sprouts to 25.99 mg TEAC/g sample after seven days of wild field cultivation. The total polyphenol content increased from 17.08 mg GA eq/100 g in cultivated field wheat sprouts grown for three days to 28.70 mg GA eq/100 g after seven days of wild field cultivation. In addition, the flavonoid content increased from 7.02 mg catechin eq/100 g (7 days) to 8.47 mg/g after 12 days of wild field cultivation. Notably, the activity subsequently decreased. These results suggest that the wheat sprouts with higher biological activity were those produced from the wild field after 20 days.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.159-162
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• 1998

Land cover and land use classification on a huge scale, e.g. national or continental scale, has become more and more important because environmental researches need land cover: And land use data on such scales. We developed a crop field extraction method, which is one of the steps in our land cover classification system for a huge area. Firstly, a crop field model is defined to characterize "crop field" in terms of NDVI value and textual information Textual information is represented by the density of straight lines which are extracted by wavelet transform. Secondly, candidates of NDVI threshold value are determined by "scale-space filtering" method. The most appropriate threshold value among the candidates is determined by evaluating the line density of the area extracted by the threshold value. Finally, the crop field is extracted by applying level slicing to Landsat TM image with the threshold value determined above. The experiment demonstrates that the extracted area by this method coincides very well with the one extracted by visual interpretation.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.520-529
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• 2017

In Korea, the largest agricultural lands are paddy fields which have poor infiltration and drainage properties. Recently, Korean government pursuits cultivating upland crops in paddy fields to reduce overproduced rice in Korea. In order to succeed this policy, it is critical to set criteria suitability classification for upland crops cultivating in paddy field soils. The objective of this study was developing guideline of suitability classification for sesame cultivation in paddy field soils. Yields of sesame cultivated in paddy field soils and soil properties were investigated at 40 locations at nationwide scale. Soil properties such as topography, soil texture, soil moisture contents, slope, and drainage level were investigated. The guideline of suitability classification for sesame was determined by multi-regression method. As a result, sesame yields had the greatest correlation with topography, soil moisture content, and slope. Since sesame is sensitive to excessive soil moisture content, paddy fields with well drained, slope of 7-15% and mountain foot or hill were best suit for cultivating sesame. Sesame yields were greater with less soil moisture contents. Based on these results, area of best suitable paddy field land for sesame was 161,400 ha, suitable land was 62,600 ha, possible land was 331,600 ha, and low productive land was 1,075,500 ha. Compared to existing suitability classification, the new guideline of classification recommended smaller area of best or suitable areas to cultivate sesame. This result may suggest that sesame cultivation in paddy field can be very susceptible to soil moisture contents.