With the growth of renewable energy use, solar energy is becoming the most popular renewable energy source worldwide. Nevertheless, the construction of a solar power plant can be a burden to a small country with a land shortage problem, because it requires extensive land. To avoid the potential food security issue caused by solar energy production, an agrivoltaic system producing both crop and solar energy is devised. This study aims to develop an integrated multi-modeling framework for an agrivoltaic system used for rice production. The proposed framework consists of four modules: (1) An environmental database module involving soil, climate, and climate change scenarios; (2) a solar energy generation estimation module predicting electricity production quantity via polynomial regression technique; (3) a crop production estimation module simulating rice yield and its impact underneath Photovoltaic (PV) panels via the Agricultural Policy/Environmental eXtender (APEX) model; and (4) a What-if analysis module analyzing the economic and environmental feasibility of an Agrivoltaic system under a climate change scenario. For validation and calibration of the proposed framework, rice production field study data underneath an Agrivoltaic system with a capacity of 107 kW at the Jeollanamdo Agricultural Research and Extension Center in Naju-si (35.0272 degrees N, 126.8247 degrees E), Jeollanam-do, South Korea, is collected. The prediction accuracy of the proposed framework is approximately 88 % in terms of the coefficient of determination. The experimental results show that the bi-facial agrivoltaic system with shading ratio of 32 % tends to have the highest total profit of USD 3.65 $/m2/day.

According to numerous chamber and free-air CO2 enrichment (FACE) studies with artificially raised CO2 concentration and/or temperature, it appears that increasing atmospheric CO2 concentrations ([CO2]) stimulates crop yield. However, there is still controversy about the extent of the yield stimulation by elevating [CO2] and concern regarding the potential adverse effects when temperature rises concomitantly. Here, we tested the effects of natural elevated [CO2] (ca. 120 ppm above the ambient level in 100 years ago) and warming (ca. 1.7–3.2 °C above the ambient level 100 years ago) on rice growth and yield over three crop seasons via a past reference investigation and current experiment (PRICE) study. In 2020–2022, the rice cultivar Tamanishiki (Oryza sativa, ssp. japonica) was grown in Wagner’s pots (1/2000 a) at the experiment fields of Chonnam National University (35°10′ N, 126°53′ E), Gwangju, Korea, according to the pot trial methodology of the reference experiment conducted in 1920–1922. Elevated [CO2] and temperature over the last 100 years significantly stimulated plant height (13.4% on average), tiller number (11.5%), and shoot biomass (10.8%). In addition, elevated [CO2] and warming resulted in a marked acceleration of flowering phenology (6.8% or 5.1 days), potentially leading to adverse effects on tiller number and grain yield. While the harvest index exhibited a dramatic reduction (12.2%), grain yield remained unchanged with elevated [CO2] and warming over the last century. The response of these crop parameters to elevated [CO2] and warming was highly sensitive to sunshine duration during the period from transplanting to heading. Despite the pot-based observations, considering a piecewise response pattern of C3 crop productivity to [CO2] of <500 ppm, our observations demonstrate realistic responses of rice crops to elevated [CO2] (+120 ppm) and moderate warming (+1.7–3.2 °C) in the absence of adaptation measures (e.g., cultivars and agronomic management practices). Hence, our results suggest that the PRICE platform may provide a promising way to better understand and forecast the net impact of climate change on major crops that have historical and experimental archived data, like rice, wheat, and soybean.

This study sought to simulate regional variation in staple crop yields in Chonnam Province, Republic of Korea (ROK), in future environments under climate change based on the calibration of crop models in the Decision Support System for Agricultural Technology Transfer 4.6 package. We reproduced multiple-year yield data for paddy rice (2013–2018), barley (2000–2018), and soybean (2004–2018) grown in experimental fields at Naju, Chonnam Province, using the CERES-Rice, CERES-Barley, and CROPGRO-Soybean models. A geospatial crop simulation modeling (GCSM) system developed using the crop models was then applied to simulate the regional impacts of climate change on the staple crops according to the Representative Concentration Pathway 4.5 and 8.5 scenarios. Simulated crop yields agreed with the corresponding measured crop yields, with root means square deviations of 0.31 ton ha−1 for paddy rice, 0.29 ton ha−1 for barley, and 0.27 ton ha−1 for soybean. We also demonstrated that the GCSM system could effectively simulate spatiotemporal variations in the impact of climate change on staple crop yield. The CERES and CROPGRO models seem to reproduce the effects of climate change on region-wide staple crop production in a monsoonal climate system. Added advancements of the GCSM system could facilitate interpretations of future food resource insecurity and establish a sustainable adaption strategy.

Agro-photovoltaic systems are of interest to the agricultural industry because they can produce both electricity and crops in the same farm field. In this study, we aimed to simulate staple crop yields under agro-photovoltaic panels (AVP) based on the calibration of crop models in the decision support system for agricultural technology (DSSAT) 4.6 package. We reproduced yield data of paddy rice, barley, and soybean grown in AVP experimental fields in Bosung and Naju, Chonnam Province, South Korea, using CERES-Rice, CERES-Barley, and CROPGRO-Soybean models. A geospatial crop simulation modeling (GCSM) system, developed using the crop models, was then applied to simulate the regional variations in crop yield according to solar radiation reduction scenarios. Simulated crop yields agreed with the corresponding measured crop yields with root mean squared errors of 0.29-ton ha−1 for paddy rice, 0.46-ton ha−1 for barley, and 0.31-ton ha−1 for soybean, showing no significant differences according to paired sample t-tests. We also demonstrated that the GCSM system could effectively simulate spatiotemporal variations in crop yields due to the solar radiation reduction regimes. An additional advancement in the GCSM design could help prepare a sustainable adaption strategy and understand future food supply insecurity.

As population rises, more people need to be fed. With increasing income, the potential exists for increases in the demand for cereals (i.e., barley). Since barley has a high level of tolerance to environmental stressors, this crop has been recommended as a potential crop for food security in marginal environments. In this study, a crop growth Agricultural Land Management Alternatives with Numerical Assessment Criteria model, was parameterized and used to simulate the yields of two barley types grown in a temperate environment at a latitude of 35 degrees N. In order to apply this crop model to barley, 19 years of field data were used to model calibration and validation. As a result, the ALMANAC model accurately simulated yields for both barley types. The validated model was used to predict yields under three diverse seasonal rainfall scenarios associated with different patterns of the Central Pacific El Nino influence. According to the simulation results, excessively high seasonal rainfall decreased barley yields. Crop price and annual revenue of the two barley types were also evaluated using a non-linear regression model. For the malt type, the food price was higher with a higher rainfall, while naked barley had a higher revenue under the conditions of a lower rainfall.

Planning for optimized farming with the aim of providing ideal site and cultivar selection is critical for a stable and sustainable supply of rice with sufficient quantity and quality to customers. In this study, a range of morphological characteristics and yield of eight rice cultivars that are commonly cultivated in Korea were investigated from 2005 to 2020. All morphological characteristics were significantly different among the eight rice cultivars. The dataset of morphological characteristics and yield was used to isolate groups of similar rice cultivars. The k-means clustering method was used to group the rice cultivars. Three groups (Group 1, Group 2, and Group 3) were created. Most cultivars were in Group 1. High-yielding rice cultivars were in Group 2, while the rice cultivars in Group 3 had the lowest rice grain yield. After grouping these rice cultivars, ideal farming locations for all three rice cultivar groups were identified to reduce transportation cost using an optimized location–allocation model. Simulation results suggested the following: (1) Group 1 should be produced in Jellanam-do (south west region), (2) Group 2 should be produced in Chungcheongnam-do (central west region), and (3) Group 3 should be mainly produced in the central west region of South Korea. Simulation results showed the potential to reduce transportation cost by around 0.014%. This can also reduce 21.04 tons of CO2 emission from a freight truck. Because these eight cultivars only make up 19.76% of the total rice production in South Korea, the cost reduction proportion was only 0.014% of total revenue. In future studies, more rice cultivars should be investigated to increase the efficiency of the model performance.

To investigate a comparison of plant growth, rice yield and quality, and occurrence of rice diseases for various rice varieties in organic cultivation, this study was carried out in rice (Oryza sativa L.) field of Bannam region, Naju. The results obtained as following: 1) Culm length was indicated in order of Dongjin 1ho>Hopyeong>Jinback>Hopum byeo. Yield of rice was indicated in order of Hopum>Hopyeong>Dongjin 1ho>Jinback byeo. 2) Rice neck blast and sheath blight were occurred mainly in Hopoombyeo. Rice strip virus was occurred only in Dongjin 1ho and Hopyeongbyeo. Sheath blight was occurred in Jinback byeo. 3) Dongjin 1ho showed protein content (5.9%), palatability value (82.3%), and Head rice (97.3%). These results indicate that Donjin 1ho was the best variety for organic cultivation in rice field.

Despite the growing body of evidence that ongoing warming modifies the cereal quality of several crop species, little is known about how it interacts with other climate change drivers. Here, we examined how elevated [CO2], warming, and extreme wet events (EWEs) would affect the grain quality of a temperate rice (Oryza sativa L.). In 2009 and 2010, plants were grown at two levels of [CO2] (c. 390 and 650 mu l l(-1)) and three levels of warming (ambient, +1.2 C and +2.2/2.4 degrees C) over the seasons in six independent temperature gradient field chambers (three each for ambient and elevated [CO2]). From 20 days after heading, plants were exposed to EWE with a simulated rainfall of 30 mm a day and cloud cover by shading (c. 18% of full sunlight) for 10 consecutive days. There were also control plots, which were non-treated (NT) in terms of EWE. We found that warming and EWE, both independently and in their interaction, lead to a significant reduction in the percentages of sound grains, whereas elevated [CO2] does not seem to do so. Not only warming and EWE, but also elevated [CO2] resulted in a significant increase of immature chalky grains (ICGs), which mostly consisted of milky-white chalky grains, degrading the grain quality. In addition, warming interacted positively with elevated [CO2] on ICGs, whereas the warming sensitivity of IGCs was moderated in EWEs: e.g., on average, the % of ICGs in ambient vs. elevated [CO2] were 8.5% vs. 9.4%, 10.7% vs. 18.1% and 17.8% vs. 29.8% at ambient (24.7 C), +1.2 degrees C and +2.4 degrees C, respectively, whereas they in NT vs. EWE were 1.2% vs. 16.6%, 7.7% vs. 21.1% and 19.4% vs. 28.2%. Our results tightly confirmed that elevated [CO2] leads to a significant reduction in rice grain protein content (PC). While warming had little effect on the PC, EWE had a significant positive effect, and the EWE-induced increase in PC was smaller in elevated (+3.3%) than in ambient [CO2] (+10.9%). Given the rice quality predictor of ICGs and PC, our findings imply that expected climate change and weather extremes have a great potential to degrade the quality of rice, in terms of its milling, cooking, eating, and nutritional quality, as well as market value. (C) 2013 Elsevier B.V. All rights reserved.

This study was conducted to find the levels of reduction in rice yield and to determine economic threshold levels as affected by densities of Scirpus planiculmis and Lindernia dubia in wet seeding rice cultivation. In wet seeding rice cultivation, yield of rice in densities of S. planiculmis (192 per m2 ) and L. dubia (384 per m 2 ) was reduced by 43 and 22%, respectively. Relationship between rice yield and densities of weeds were predicted with these equations of Y=531.3kg/(1+0.003931x), r 2 =0.964 for S. planiculmis and Y=547.0kg/(1+0.000792x), r 2 =0.922 for L. dubia. According to Cousens' method, economic threshold densities of S. planiculmis and L. dubia were calculated by 7.2 and 34.9 per m 2 , respectively. This result indicat ed that yield of rice in wet seeding rice cultivation could be reduced by over economic threshold densities of S. planiculmis and L. dubia.

The objective of this research was to find out the weed management techniques in environment-friendly rice paddy fields through the study on herbicidal effects and problems of various organic materials. This experiment was conducted under different conditions of weed species and weed densities in environment-friendly rice paddy fields. There was no difference in weedy efficacy on golden apple snail (GAS), paper mulching (PM), and machine weeding (MW) between low and high weed densities. However, the effect of weed control in rice bran (RB) and effective microorganism (EM) + molasses was higher in high weed density than in low weed density. In general, the effect of weed control as affected by various organic materials was in the order of GAS (97-100%) > PM (93-98%) > RB (15-80%) > EM (7-31%). GAS provided excellent control of all weed species tested except for Persicaria hydropiper. PM gave acceptable control of the weed species except for Echinochloa crus-galli, Ludwigia prostrata, and Eleocharis kuroguwai. However, MW gave fair control (70% biomass reduction) of all weed species tested. BR followed by MW or EM followed by MW treatments had similar effect on weed control compared to each treatment alone. However, BR followed by GAS or EM followed by GAS provided 100% control of weed species tested. The level of rice foliar injury caused by various organic materials was in the order of GAS and MW (10-20%) > RB (10-15%) > PM and EM (5-7%). Typical symptoms of organic materials are wilting, inhibition of growth, missing hill, and reduction of tiller. Cost for weed control of GAS, RB, EM, and PM were 2.1, 3.1, 2.3, and 13.2 times higher than that of the

A bacterium, KJA-118 showing a strong chitinase activity, was isolated and identified as Bacillus cereus. The strain produced maximum level of chitinase, when grown aerobically at for 4 days in basal broth containing 1% colloidal chitin in the initial pH adjusted to 6.0. Among various carbon sources such as crab shell powder, chitin powder, colloidal chitin, and R. solani mycelium, maximum chitinase activity was found in culture broth supplemented with R. solani mycelium. When KJA-118 was incubated with R. solani, the cell wall of the fungus was found to be completely destroyed. SDS-PAGE and active staining results revealed that KJA-118 produced three isoforms of chitinase with molecular weights of 68 kDa, 47 kDa, and 37 kDa. When the suspension of KJA-118 was treated to cucumber seedlings, reducing rate of damping-off caused by R. solani was about 28.1%.

A bacterium having strong chitinolytic activity on 0.2% colloidal chitin-containing agar medium was isolated from coastal soil in Korea. Based on the nucleotide sequence of a conserved segment of a 16S rRNA gene, the bacterium was identified as Paenibacillus illinoisensis KJA-424. The population of P illinoisensis KJA-424 and chitinase activity significantly increased for the first 2 days of incubation. On SDS-PAGE analysis with 0.01% glycol chitin, three protein bands (63, 54, and 38 kDa) with chitinolytic activity were detected. The effect of P illinoisensis KJA-424 on the egg hatch of root-knot nematode (Meloidogyne incognita) was investigated. After 7 days of incubation with the chitinase-producing P. illinoisensis KJA-424, none of the eggs hatched, whereas a 39.8% egg hatching rate was observed in the water control. Inverted and scanning electron microscopic observations demonstrated that P illinoisensis KJA-424 deformed and destroyed the eggshell of M. incognita. In conclusion, chitinase produced by P illinoisensis KJA-424 caused the lysis of M. incognita eggshell and resulted in the inhibition of egg hatching in vitro.