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Smart farm is a breakthrough technology that can maximize crop productivity and economy through efficient utilization of space regardless of external environmental factors. This study was conducted to investigate the optimal growth and physiological conditions of Chinese matrimony vine (Lycium chinense) with LED light sources in a smart farm. The light source was composed of red+blue and red+blue+white mixed light using a LED system. In the red+blue mixed light, red and blue colored LEDs were mixed at ratios of 1:1, 2:1, 5:1, and 10:1, with duty ratios varied to 100%, 99%, and 97%. The experimental results showed that the photosynthetic rate according to the types of light sources did not show statistically significant differences. Meanwhile, the photosynthetic rate according to the mixed ratio of the red and the blue light was highest with the red light and blue LED ratio of 1:1 while the water use efficiency was highest with the red and blue LED ratio of 2:1. The photosynthetic rate according to duty ratio was highest with the duty ratio of 99% under the mixed light condition of red+blue+white whereas the water use efficiency was highest with the duty ratio of 97% under the mixed light of red+blue LED. The results indicate that the light source and light quality for the optimal growth of Lycium chinense in the smart farm using the LED system are the mixed light of red+blue (1:1) and the duty ratio of 97%.

Background The sunfleck is an important light environmental factor for plants that live under the shade of trees. Currently, the smartfarm has a system that can artificially create these sunfleks. Therefore, it was intended to find optimal light conditions by measuring and analyzing photosynthetic responses of Eutrema japonica (Miq.) Koidz., a plant living in shade with high economic value under artificial sunflecks. Results For this purpose, we used LED pulsed light as the simulated sunflecks and set the light frequency levels of six chambers to 20 Hz, 60 Hz, 180 Hz, 540 Hz, 1620 Hz, and 4860 Hz of a pulsed LED grow system in a plant factory and the duty ratio of the all chambers was set to 30%, 50%, and 70% every 2 weeks. We measured the photosynthetic rate, transpiration rate, stomatal conductance, and substomatal CO2 partial pressure of E. japonica under each light condition. We also calculated the results of measurement, A/Ci, and water use efficiency. According to our results, the photosynthetic rate was not different among different duty ratios, the transpiration rate was higher at the duty ratio of 70% than 30% and 50%, and stomatal conductance was higher at 50% and 70% than at 30%. In addition, the substomatal CO2 partial pressure was higher at the duty ratio of 50% than 30% and 70%, and A/Ci was higher at 30% than 50% and 70%. Water use efficiency was higher at 30% and 50% than at 70%. While the transpiration rate and stomatal conductance generally tended to become higher as the frequency level decreased, other physiological items did not change with different frequency levels. Conclusions Our results showed that 30% and 50% duty ratios could be better in the cultivation of E. japonica due to suffering from water stress as well as light stress in environments with the 70% duty ratio by decreasing water use efficiency. These results suggest that E. japonica is adapted under the light environment with nature sunflecks around 30–50% duty ratio and low light frequency around 20 Hz.

BackgroundTo investigate the trends of succession occurring at thePinus thunbergiiforests on the lowlands of Jeju Island, we quantified the species compositions and the importance values by vegetation layers of Braun-Blanquet method on thePinus thunbergiiforests. We used multivariate analysis technique to know the correlations between the vegetation group types and the location environmental factors; we used the location environment factors such as altitudes above sea level, tidal winds (distance from the coast), annual average temperatures, and forest gaps to know the vegetation distribution patterns.ResultsAccording to the results on the lowland of Jeju Island, the understory vegetation of the lowlandPinus thunbergiiforests was dominated by tall evergreen broad-leaved trees such asMachilus thunbergii,Neolitsea sericea, andCinnamomum japonicumshowing a vegetation group structure of the mid-succession, and the distribution patterns of vegetation were determined by the altitudes above sea level, the tidal winds on the distance from the coast, the annual average temperatures, and the forest gaps. We could discriminate the secondary succession characteristics of thePinus thunbergiiforests on the lowland and highland of Jeju Island of South Korea.ConclusionsIn the lowland of Jeju Island, the secondary succession will progress to the form ofPinus thunbergii(early successional species)→Machilus thunbergii,Litsea japonica(mid-successional species)→Machilus thunbergii(late-successional species) sequence in the temperate areas with strong tidal winds. In the highland of Jeju Island, the succession will progress to the form ofPinus thunbergii(early successional species)→Neolitsea sericea,Eurya japonica(mid-successional species)→Castanopsis sieboldii(late-successional species) sequence in the areas where tidal winds are weak and temperatures are relatively low. However, local differences between lowland and highland of Jeju Island will be caused by the micro-environmental factors resulting from the topographic differences and the supply of tree seeds. From the characteristics of succession study, we could properly predict and manage thePinus thunbergiiforest ecosystem on lowland and highland of Jeju Island.

Background The Northern Hemisphere forest ecosystem is a major sink for atmospheric carbon dioxide, and the subalpine zone stores large amounts of carbon; however, their magnitude and distribution of stored carbon are still unclear. Results To clarify the carbon distribution and carbon budget in the subalpine zone at volcanic Jeju Island, Korea, we report the C stock and changes therein owing to vegetation form, litter production, forest floor, and soil, and soil respiration between 2014 and 2016, for three subalpine forest ecosystems, namely, Abies koreana forest, Taxus cuspidata forest, and Juniperus chinensis var. sargentii forest. Organic carbon distribution of vegetation and NPP were bigger in the A. koreana forest than in the other two forests. However, the amount of soil organic carbon distribution was the highest in the J. chinensis var. sargentii forest. Compared to the amount of organic carbon distribution (AOCD) of aboveground vegetation (57.15 t C ha−1) on the subalpine-alpine forest in India, AOCD of vegetation in the subalpine forest in Mt. Halla was below 50%, but AOCD of soil in Mt. Halla was higher. We also compared our results of organic carbon budget in subalpine forest at volcanic island with data synthesized from subalpine forests in various countries. Conclusions The subalpine forest is a carbon reservoir that stores a large amount of organic carbon in the forest soils and is expected to provide a high level of ecosystem services.

Background Standing biomass, litter production, rate of litter decomposition, amount of litter on forest floor, and amount of soil organic carbon distribution were investigated from March 2016 to November 2018 in order to evaluate the ecosystem value through organic carbon distribution in the Pinus densiflora forest at Namsan, Seoul Metropolitan City. Results The amount of organic carbon in the Pinus densiflora forest was 261.09 ton C ha−1 during the research period, and fixed organic carbon in plant through net photosynthesis was 3.2 ton C ha−1 year−1. The organic carbon in plant was 62.77 ton C ha−1 (24.04%), in litter on the forest floor was 3.65 ton C ha−1 (1.40%), and in soil was 194.67 ton C ha−1 (74.56%). The value of plant, litter on forest floor, and soil organic carbon distribution were each 6,277,000 won ha−1, 365,000 won ha−1, and 19,467,000 won ha−1. The value per ton of fixed organic carbon in plant through net photosynthesis was 320,000 won ha−1 year−1 and the value of ecosystem services stored in carbon in the Namsan forest ecosystem was about 26.1 million won ha−1 for 3 years. Conclusions The results of this study suggest that the pine forests of Namsan rapidly decompose leaves due to the high atmospheric temperature and accumulate a large amount of organic carbon in the soil to provide climate control regulatory service function.

In this study, we observed their growth and physiological responses using a variety of duty ratio under the mixed light using red, blue, and white lights. The red+blue mixed light was treated with 95%, 90%, 85%, 80%, and 75% duty ratios and red+blue+white mixed light with 85% and 70% duty ratios. We examined the width and length of leaves, total number of leaves, and number of shoots to examine their growth responses. The physiological responses were studied by measuring their photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, chlorophyll content, and fluorescence (Fo, Fm, and Fv/Fm). We found that lower duty ratio caused the length and width of the leaves to grow longer under red+blue mixed light but that it did not cause any difference in the red+blue+white mixed light condition. In addition, there was no difference in the number of leaves and shoots among all treatments. In the red+blue mixed light condition, the photosynthetic rate was no difference, but both transpiration rate and stomatal conductance were the highest at 95% duty ratio than in other ratios. Water use efficiency pattern was similar to that of photosynthetic rate; water use efficiency was no difference. Chlorophyll content was the highest at 95% duty ratios, and it was the least at 90%, 85%, and 75% duty ratio. Fo and Fm values were relatively high at 85% and 80% duty ratio and low at 90% duty ratio while Fv/Fm showed no difference. Under the red+blue+white mixed light, all physiological items showed no difference between 70 and 85% treatments. But, photosynthetic rate, water use efficiency, chlorophyll content, and Fv/Fm were relatively greater in the red+blue+white mixed light than in the red+blue mixed light. Therefore, red+blue+white mixed light treated with 70% duty ratio could lessen the environmental stress and save more power when cultivating Silene capitata in a plant factory.

This study was conducted from March 2011 to February 2013 in order to evaluate the ecosystem value by examining the organic carbon distribution and cycling in the Quercus glauca forest, evergreen oak community at Seonheul-Gotjawal, Jeju Island. The amount of organic carbon distribution was 124.5 ton C ha− 1 in 2011 and 132.63 ton C ha− 1 in 2012 for aboveground biomass. And it was 31.13 ton C ha− 1 in 2011 and 33.16 ton C ha− 1 in 2012 for belowground biomass. In total, the amount of organic carbon distribution in plants was 155.63 and 165.79 ton C ha− 1 in 2011 and 2012, respectively. In 2011 and 2012 respectively, the amount of organic carbon distribution was 3.61 and 6.39 ton C ha− 1 in the forest floor and it was 78.89 and 100.71 ton C ha− 1 in the soil. As shown, most carbon was distributed in plants. Overall, the amount of organic carbon distribution of the Q. glauca forest was 238.13 ton C ha− 1 in 2011 and 272.89 ton C ha− 1 in 2012. In 2011, the amount of organic carbon fixed in plants through photosynthesis (NPP) was 14.22 ton C ha− 1 year− 1 and the amount of carbon emission of soil respiration was 16.77 ton C ha− 1 year− 1. The net ecosystem production (NEP) absorbed by the Q. glauca forest from the atmosphere was 5 ton C ha− 1 year− 1. The carbon storage value based on such organic carbon distribution was estimated about 23.81 mil won ha− 1 in 2011 and 27.29 mil won ha− 1 in 2012, showing an annual increment of carbon storage value by 3.48 mil won ha− 1. The carbon absorption value based on such NEP was estimated about 500,000 won ha− 1 year− 1.

【This research was conducted to examine the changes in growth and production of Oryza sativa L. cv. Ilmi, which was developed to cultivate high yielding rice variety in the Southern plains of Korea. The seedlings of the rice were cultivated from May to October in 2012 under three different conditions: control, AC-AT, ambient $CO_2$ + ambient temperature; AC-ET, ambient $CO_2$ + elevated temperature; EC-ET, elevated $CO_2$ + elevated temperature. The aboveground biomass, belowground biomass, the total biomass of the rice, and panicle weight per individual were the heaviest in the EC-ET. But, the number of grains per panicle and the weight of one grain was higher at the condition of AC-ET and EC-ET than that of AC-AT. The number of tiller was higher at the condition of AC-AT and AC-ET than that of EC-ET. However, there was no significant difference in the number of panicles per individual and the ripened grain rate among the control and global warming treatments. Crop yield was the highest in the EC-ET. This result means that the global warming condition should be considered in the selection of suitable paddy field for the limibyeo in the future.】

In this study, the growth and reproductive response of seedlings, grown in plastic pots with sand, to moisture and nutrients were analyzed in order to study the environmental conditions required to create an alternative habitat for Epilobium hirsutum L., an endangered plant. Vegetative and reproductive growths of Epilobium hirsutum L. are accelerated with increase in moisture and organic matter content in the soil. Among vegetative organs, the number of runners related to asexual reproduction was the highest when the moisture content was over 25% and nutrient content between 7 and 14% in the soil. But the number of flowers related to flowering responses, among reproductive organs, was the highest when the moisture content was maintained at 75% and when nutrient content was 21% in the soil. The number of seeds, related to sexual reproduction, was the highest when the moisture content was over 25% and nutrient content between 14 and 21%. The study results show that a place with high moisture and nutrient content in the soil is advantageous to asexual and sexual reproduction of Epilobium hirsutum L. Therefore, we must serve periodically nutrient and seeds to sustain population in in situ conservation. Furthermore, it is advisable to create in riverside where abundant nutrient content have, making alternative habitat of Epilobium hirsutum L. Also, we must find species that have high contribution degree index through vegetation survey.

In order to investigate organic carbon distribution, carbon budget, and cycling of the subalpine forest, we studied biomass, organic carbon distribution, litter production, forest floor litter, accumulated soil organic carbon, and soil respiration in Taxus cuspidata forest in Halla National Park from February 2012 to November 2013. Biomass was calculated by using allometric equation and the value was converted to CO2 stocks. The amount of plant organic carbon was 13.60 ton C ha−1year−1 in 2012 and 14.29 ton C ha−1year−1 in 2013. And average organic carbon introduced to forest floor through litter production was 0.71 ton C ha−1year−1. Organic carbon distributed in forest floor litter layer was 0.73 ton C ha−1year−1 on average and accumulated organic carbon in soil was 51.13 ton C ha−1year−1 on average. In 2012, Amount of released CO2 from soil to atmosphere was 10.93 ton CO2 ha−1year−1. The net ecosystem production based on the difference between net primary production of organic carbon and soil respiration was −1.74 ton C ha−1yr−1 releasing more carbon than it absorbed.