• Original Research Article

    Analysis of changes in plant nitrogen accumulation and distribution in rice (Oryza sativa L.) under shading at major growth stages

    벼 주요 생육기별 차광에 따른 식물체 질소 축적 및 분배 변화 분석

    Woon-Ha Hwang, Min-Ji Lee

    황운하, 이민지

    Crop damage caused by shading has been increasing due to rapid urbanization and climate change. In this study, we analyzed changes in … + READ MORE
    Crop damage caused by shading has been increasing due to rapid urbanization and climate change. In this study, we analyzed changes in dry weight, nitrogen content, and accumulated 15N content under different shading rates at major growth stages in rice. As the shading rate increased, dry weight tended to decrease. A marked reduction in dry weight was observed under 55% shading during the basic vegetative phase (BVP) and reproductive phase (REP), and under 65% shading during the ripening phase (RIP) and whole growth period (WH). When shading was applied during the BVP, the stem dry weight decreased substantially. Under shading during REP, the dry weight of all plant parts decreased, indicating that this was the stage most sensitive to shading. Under shaded conditions, the nitrogen content per unit weight tended to increase. In particular, strong negative correlations were observed between dry weight and nitrogen content in the stem during the BVP and in the leaves during the REP. Root-derived 15N was mainly distributed in the stem under non-shading conditions, whereas shading decreased total 15N accumulation and altered its distribution, with a relatively higher allocation to leaves. - COLLAPSE
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    1 September 2026

  • Original Research Article

    Heading Classification of Rice Cultivar Groups Using Time-Series RGB Drone Images and a Deep-Learning-Based Classification Model

    드론 시계열 RGB 영상과 딥러닝 기반 분류 모델을 이용한 벼 품종군의 출수 판별

    Yunjeong Jeong, Hyeonggyun Kim, Do-hyun Kim, Wangyu Sang, Dongwon Kwon, Woojin Im, Dasom Jeon, Huisu Bae, Sungyul Chang

    정윤정, 김형균, 김도현, 상완규, 권동원, 임우진, 전다솜, 배희수, 장성율

    The rice heading date is a critical phenological indicator when optimizing crop management and determining harvest timing. Traditional assessments rely on manual … + READ MORE
    The rice heading date is a critical phenological indicator when optimizing crop management and determining harvest timing. Traditional assessments rely on manual visual inspections, which are prone to observer bias and are difficult to scale in breeding programs. In this study, we evaluated the feasibility of automated heading date estimation using unmanned aerial vehicle (UAV)-based time-series red-green-blue (RGB) imagery. This study was conducted using 144 rice cultivars at the National Institute of Crop Science, Wanju-gun, Jeollabuk-do, Republic of Korea. RGB imagery was acquired at three time points (08:00, 12:00, and 16:00), processed into orthomosaics, and partitioned into 100 × 100 pixel patches to create a dataset of 79,331 images. These images were labeled as pre-heading or heading, based on ground truth data. A YOLOv11-based classification model, initialized using ImageNet pre-trained weights, was employed, and its decision-making process was visualized using Grad-CAM. The model achieved a final accuracy of 0.953 and training loss of 0.142. Although the confusion matrix demonstrated high overall classification performance, misclassifications were primarily concentrated in the early heading stage. A comparison between predicted and observed heading dates across maturity groups indicated statistically significant differences. The predicted heading dates had a mean bias of 1.89 days, indicating a tendency to estimate heading dates later than the field observations. The mean absolute error and root-mean-square error were 2.14 and 2.66 days, respectively, and the predicted heading dates of 60.42% of the cultivars were within ±2 days of the observed heading dates. Grad-CAM analysis confirmed that the model focused on panicle features as the primary classification criterion. These findings suggest that UAV-based YOLO models have potential as a phenotyping support tool for consistent heading date assessment across large numbers of rice cultivars. Further refinement through additional early-heading data and improved temporal decision criteria may decrease prediction delays and increase the applicability of the model to automated crop growth monitoring. - COLLAPSE
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    1 September 2026

  • Original Research Article

    Evaluation of Efficacy, Phytotoxicity, and Residues of Two Non-Selective Herbicides in Pre-Transplant Rice Paddy Fields

    이앙 전 논에서 비선택성 제초제 2종의 처리에 대한 약효·약해 및 잔류성 평가

    Yun-Ho Lee, Ji-Hoon Kim, Seung-Hyen Park

    이윤호, 김지훈, 박승현

    This study was conducted to evaluate the weed-control efficacy, phytotoxicity, and residue levels of two non-selective herbicides, glufosinate ammonium at 18.0% and … + READ MORE
    This study was conducted to evaluate the weed-control efficacy, phytotoxicity, and residue levels of two non-selective herbicides, glufosinate ammonium at 18.0% and glufosinate ammonium–tiafenacil at 16.8%, applied 15 days before flooding in transplanted rice cultivation. Field experiments were conducted in Wanju and Nonsan, Republic of Korea, to allow their effectiveness against weedy rice and annual weeds, as well as their safety when applied to rice plants and residue persistence in harvested products to be assessed. In Wanju, the control efficacies of glufosinate ammonium at 18.0% and glufosinate ammonium–tiafenacil at 16.8% against weedy rice and annual weeds were 97.9% and 98.8%, respectively. In Nonsan, the corresponding control efficacies were 98.1% and 100.0%, respectively. These results demonstrated excellent weed-control performance for both herbicides across locations. Phytotoxicity assessments revealed no visible injury symptoms in rice plants at either the recommended application rate or twice the recommended rate for both herbicides when compared with the hand-weeded control. Furthermore, residue analysis conducted after harvest demonstrated that herbicide residues in brown rice and rice straw were below the detection limit (<0.01 mg kg-1) in all treatments. The results indicate that the application of glufosinate ammonium at 18.0% and glufosinate ammonium–tiafenacil at 16.8% 15 days before flooding provides effective control of weedy rice and annual weeds without exerting phytotoxic effects on rice plants or leaving detectable residues in harvested products. Therefore, these herbicides can be safely utilized as an effective pre-flood weed-management strategy in transplanted rice cultivation. - COLLAPSE
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    1 September 2026

  • Original Research Article

    Evaluation of Irrigation Criteria and Nitrogen Topdressing Rate for Soybean under Subsurface Drip Fertigation

    지중점적관비 재배에서 관수 기준 및 질소 추비량에 따른 콩 생육과 수량 반응

    Jong Hyuk Kim, Yeon Ju Lee, Ye Rin Kim, Do Hui Kim, Seo Young Mun, Il Rae Rho

    김종혁, 이연주, 김예린, 김도희, 문서영, 노일래

    To establish irrigation and nitrogen fertigation criteria for soybean (Glycine max (L.) Merr.) under subsurface drip fertigation (SDF), sequential pot and … + READ MORE
    To establish irrigation and nitrogen fertigation criteria for soybean (Glycine max (L.) Merr.) under subsurface drip fertigation (SDF), sequential pot and field experiments were conducted under sandy loam soil conditions. In 2021, the amount of irrigation required and electrical conductivity (EC) of the nitrogen-based fertigation solution were evaluated, and in 2022, field responses to nitrogen topdressing rates were examined. The amount of irrigation required to supply water to the soil surface was 24.3 ton/10a. In the pot experiment, EC 1.0 (N 2.4 kg/10a) facilitated the greatest nitrogen uptake, growth, and yield. Based on this result, field treatments were established with total nitrogen topdressing rates of N 2, 4, and 6 kg/10a, split equally between the R1 and R2 stages. In the field experiment, growth tended to increase with increasing nitrogen application rate, whereas seed yield was highest under treatment N2, which was 27.4% higher than that of the control. The number of nodules was also highest under N2 and decreased with increasing nitrogen topdressing rate. These results suggest that, in the sandy loam environment of this study, SDF at 24.3 ton/10a per fertigation event, with a total nitrogen topdressing of 2 kg/10a split between R1 and R2, is suitable for improving nodule formation and seed yield in soybean. - COLLAPSE
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    1 September 2026

  • Original Research Article

    Characteristics of Korean Wheat (Triticum aestivum L.) Seeds According to Their Spikelet Position During the Maturation Period

    국내 밀(Triticum aestivum L.) 품종별 이삭 위치에 따른 종실 특성 분석

    Sejin Oh, Yumi Lee, Jaeyoung Ock, Gitak Ryu, Seul Lee, Seong-Wook Kang, Jin-Seong Moon, Jinyoung Moon, Jin-Young Kim, Seong-Woo Cho

    오세진, 이유미, 옥재영, 류기탁, 이슬, 강성욱, 문진성, 문진영, 김진영, 조성우

    In this study, we comparatively analyzed the morphological characteristics, starch and amino acid accumulation, and gene expression levels of Korean wheat seeds … + READ MORE
    In this study, we comparatively analyzed the morphological characteristics, starch and amino acid accumulation, and gene expression levels of Korean wheat seeds according to their spikelet position at 35 days after anthesis. The area, length, width, and dry weight of apical seeds were all lower than those of central or basal seeds (5.1-25.5%), indicating relatively limited seed development. Amino acid analysis showed that the contents of total amino acids (7.6-34.6%) and storage protein-related amino acids, including glutamic acid (8.9-9.6%), proline (10.1-21.8%), methionine (5.9-42.4%), and cystine (3.2-25.0%), were generally higher in central or basal seeds. Apical seeds had lower contents of amylopectin (5.4-13.3%) and amylose (18.0-52.6%) than those in central or basal seeds. Gene expression analysis revealed that sugar transport and starch biosynthesis were regulated differently among apical, central, and basal seeds. The Sugars Will Eventually Be Exported Transporter (SWEET) expression level was 43.2-79.9% higher in apical seeds than in central or basal seeds. The sucrose transporter (SUT) expression level tended to be 44.3-97.4% higher in central or basal seeds than in apical seeds. By contrast, the expression levels of starch biosynthesis-related genes, including ADP-glucose pyrophosphorylase (AGPase), starch branching enzyme I (SBEI), and debranching enzyme (DBE), were generally higher in central or basal seeds. These results suggest that starch biosynthesis is more active in central or basal seeds. In conclusion, apical seeds exhibited relatively low development and storage protein-related amino acid and starch accumulation, whereas central or basal seeds showed enhanced starch and amino acid accumulation during the late maturation period. - COLLAPSE
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    1 September 2026
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