This study investigated seasonal water quality characteristics and changes in agricultural watersheds of Jeollanam-do from 2021 to 2024 and analyzed their relationships with farmland proportion and precipitation using the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI).The results showed that during periods of high rainfall, concentrations of COD and SS significantly increased, and water quality deterioration was more pronounced in areas with higher farmland proportions.Strong negative correlations were observed between CCME-WQI and key water quality indicators such as COD, T-N, and T-P, indicating their significant contribution to water quality degradation.These findings suggest that CCME-WQI is a suitable tool for integrated water quality assessment in agricultural watersheds and may can serve as a basis for analyzing pollution sources and establishing effective management strategies under changing agricultural environments.For sustainable water quality management, further investigation of non-point pollution sources and long-term monitoring is recommended.

Drainage class is a critical factor in evaluating soil for crop suitability, water management, and sustainable agricultural planning.Traditional classification methods, which rely on field surveys and expert judgment, can be subjective.This study aims to establish objective criteria for soil drainage classification by analyzing color properties extracted from soil images.A total of 88 soil samples were collected from diverse parent materials and drainage classes.Soil colors were quantified using the Munsell soil color system, HSV, and CIELAB color spaces.In well drained and moderately well drained soils, matrix colors exhibited high chroma (3), while redoximorphic features showed low chroma (1 -2), indicating strong oxidizing conditions.In contrast, poorly drained soils displayed grayish matrix colors with low chroma (2) and reddish mottles with high chroma (4), reflecting alternating redox conditions.Hue values in the HSV space and a* (red -green axis of the CIELAB color space) values in the CIELAB space were particularly effective in distinguishing drainage classes: well drained soils generally had higher Hue and a* values, whereas poorly drained soils tended toward lower Hue and negative a* values.Phyllite derived soils exhibited unique characteristics due to the inherent color of the parent material, highlighting the need for integrated interpretation.These findings demonstrate that digital image based soil color analysis, particularly using Hue and a* values, provides a quantitative and scalable approach to classifying soil drainage classes.

Korea is one of countries that have high application rate of organic fertilizer and is known to cause significant environments issues.The use of inorganic fertilizer has led to a nutrient supply that exceeds the nutrient requirements of crops, resulting in an excess of nutrients in agricultural soil.Hence, many agricultural policies have been legislated to reduce the fertilizer application rate since 1990s.This study aims to investigate fertilizer type and usage on food crops (rice, barley, bean, potato, sweet potato, corn) in 9 provinces in 2019 and 2023.The average of total fertilizer inputs (N-P 2 O 5 -K 2 O) showed a slight decrease in both inorganic and organic fertilizers in 2023 compared to 2019, while compost increased.In terms of N, the total fertilizer usage was highest for potato (37.0 kg 10a -1 ) in 2019 and for corn (37.7 kg 10a -1 ) in 2023.Moreover, the fertilizer usage for all crops exceeded the recommended levels.As a result, a primary concern is the excessive use of fertilizers, with a focus on compost.Because of the high nutrient content of compost, the application rate of compost should be controlled and monitored.Therefore, the proper training and monitoring are required to promote proper nutrient management of fertilizer in food crops cultivation.

Microplastic accumulation in agricultural soils poses a growing environmental concern, affecting soil fertility, microbial communities, and crop productivity.This paper reviews current knowledge of soil microplastic toxicity, summarizes documented effects on plant and soil processes, and proposes a strategy for targeted analyses using existing soil archives.While laboratory and field studies have provided valuable mechanistic insights, their limited spatial and temporal scope constrains real-world applicability.Studies in soil systems, particularly those accounting for the origin, distribution, and environmental behavior of microplastics, are still limited.Moreover, current soil and crop evaluations often rely on single polymer type and assume a linear relationship with crop toxicity, which remains questionable.This study highlights the lack of data capturing both spatial and temporal variability of microplastics in the agricultural soils.Notably, no comprehensive Korean database currently links soil microplastic contamination to crop growth and yield under field conditions.Establishing such a database is essential to support risk assessment, agricultural management, and improving biogeochemical modeling tailored to Korean soils and cropping systems.Therefore, a unified information system for agricultural microplastic management is needed to integrate physiological and biogeochemical data across scales.

Reclaimed tidelands (RTLs) in Korea were originally developed for rice cultivation; however, converting paddy to upland field is encouraged to improve grain self-sufficiency.However, due to poor drainage, high salinity, and low nutrient availability, cultivating upland crops in RTLs have many challenges.Furthermore, frequent extreme weather events, such as precipitation, heatwaves, and droughts, uncertainty of cultivation management is increasing.Therefore, this study was conducted to evaluate the effect of slope construction on improving drainage through soil water content, and to analyze the effects of drought on soil water and soybean (Glycine max L. Merr.) growth in sloped and flat fields.Slope construction, in combination with high saturated hydraulic conductivity (0.07 cm hr -1 ) and surface drainage, led to a rapid decrease in soil water content after rainfall, which is benefit to reduce excess moisture injury for soybean during heavy rain season.However, after monsoon season, low precipitation caused soil water content to drop below 10%.Furthermore, prolonged high temperature from July to September, which includes flowering and pod-filling stages, caused sterility of pods and reduced overall yield.Such yield reduction was more prominent in sloped plot due to improved drainage efficiency.This study highlights the need for effective climate-resilient water management strategies, including irrigation and drainage, to support sustainable soybean cultivation in reclaimed tidelands.

This study evaluated the applicability of iron-based precipitate (IBP), primarily composed of ferric hydroxide, as a stabilizing agent to reduce the leaching of nitrogen (T-N) and phosphorus (T-P) from livestock manure compost.The mineralogical properties of IBP include an amorphous structure with a high Fe 2 O 3 content (71.7%), a specific surface area of 266.17 m 2 g -1 , and mesopores with an average pore size of 3.93 nm.Results from the toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) tests indicated a low environmental risk, showing undetectable or minimal concentrations of heavy metals, T-N, and T-P.Column experiments were conducted using cow and pig manure composts amended with 5wt% and 10wt% IBP.A synthetic acid rain solution, based on the SPLP method, was continuously applied for five years to simulate rainfall conditions.The results demonstrated that the addition of IBP generally reduced the leaching concentrations of both T-N and T-P.In pig manure compost, T-N was reduced by up to 11.1% and T-P by 47.9% with the 10 wt% IBP addition.On the other hand, cow manure compost exhibited a relatively lower reduction efficiency.These findings were consistent with previous batch test results, particularly for phosphorus stabilization.Overall, this study demonstrates that iron-based precipitate is effective in reducing the leaching of nutrients (N and P) from livestock manure compost and poses minimal environmental risk.Therefore, IBP is expected to be utilized as an eco-friendly stabilization strategy to mitigate agricultural non-point source pollution and prevent eutrophication in adjacent water systems.