• Journal of Environmental Science International
• /
• v.25 no.8
• /
• pp.1143-1153
• /
• 2016

Plant biomass, photosystem II (PSII) photochemical activity, photosynthetic function, and zinc (Zn) accumulation were investigated in a sorghum-sudangrass hybrid (Sorghum bicolor ${\times}$ S. sudanense) exposed to various Zn concentrations to determine the elimination capacity of Zn from soils. Plant growth and biomass of the sorghum-sudangrass hybrid decreased with increasing Zn concentration. Symptoms of Zn toxicity, i.e., withering and discoloration of old leaves, were found at Zn concentrations over 800 ppm. PSII photochemical activity, as indicated by the values of $F_v/F_m$ and $F_v/F_o$, decreased significantly three days after exposure to Zn concentrations of 800 ppm or more. Photosynthetic $CO_2$ fixation rate (A) was high between Zn concentrations of 100-200 ppm ($22.5{\mu}mol$ $CO_2{\cdot}m^{-2}{\cdot}s^{-1}$), but it declined as Zn concentration increased. At Zn concentrations of 800 and 1600 ppm, A was 14.1 and $1.8{\mu}mol$ $CO_2{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. The patterns of stomatal conductance ($g_s$), transpiration rate (E), and water use efficiency (WUE) were all similar to that of photosynthetic $CO_2$ fixation rate, except for dark respiration ($R_d$), which showed an opposite pattern. Zn was accumulated in both above- and below-ground parts of plants, but was more in the below-ground parts. Magnesium (Mg) and iron (Fe) concentrations were significantly low in the leaves of plants, and symptoms of Mg or Fe deficiency, such as a decrease in the SPAD value, were found when plants were treated with Zn concentrations above 800 ppm. These results suggest that the sorghum-sudangrass hybrid is able to accumulate Zn to high level in plant body and eliminate it with its rapid growth and high biomass yield.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.1
• /
• pp.91-97
• /
• 2011

The objectives of this research were to investigate the system of rice intensification (SRI) on early growth, grain yield, and yield components under Chinese milk vetch residue-mulched no-tillage cropping systems at silt loam soil. The field was prepared as a split-plot design with three replications, main plots consisted of Dongjinbyeo, and Sobibyeo as a cultivar, and subplots consisted of $10{\times}10$ cm, $20{\times}20$ cm, and $30{\times}30$ cm as a planting density. Weed infestation during rice growing season was more severe in wider planting density $30{\times}30$ at 35 days after transplanting (DAT), and $20{\times}20$ cm at 95 DAT in both Sobibyeo and Dongjinbyeo. The maximum plant height was recorded in Sobibyeo compared with Dongjinbyeo, $10{\times}10$ cm and $20{\times}20$ cm planting density compared with $30{\times}30$ cm from 20 DAT until 60 DAT. Among the three planting densities, SPAD values were significantly greater in planting density of $20{\times}20$ cm both in Sobibyeo and Dongjinbyeo followed by $30{\times}30$ cm compared with closer planting density of $10{\times}10$ cm. The lowest grain yield was observed in wider planting density of $30{\times}30$ in both Sobibyeo and Dongjinbyeo due to lower number of panicle per unit area. Our findings suggest that optimum planting density for SRI in no-tillage paddy was $20{\times}20$ cm and it should be useful the systems to small-scale rice farmers in Korea as a sustainable farming system.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.21 no.2
• /
• pp.53-58
• /
• 2001

Jeju Italian millet was grown at five planting densities(5$\times$5, 15$\times$15, 20$\times$20, 25cm) form May 13 to Aug. 14, 2000 at jeju island to determine influence of planting density on agronomic characters, forage yield and quality. Days to heading increased from 87 to 89 days as planting density was decreased. In 5$\times$5cm planting density plot, plant height was 185.4cm and it was gradually decreased as planting density was increased. So in 30$\times$30cm planting density plot, plant height was 173cm. As planting density increased, stem diameter, the number of nodes per plant, the umber of leaves, leaf width and SPAD reading values was increased, the longer leaf length as the broader planting density. Fresh forage yield increased from 29.99 to 55.01MT/ha, dry matter(DM) yield from 8.04 to 15.59MT/ha, crude protein(CP) yield from 0.78 to 2.26MT/ha and total digestible nutrients(TDN) yield from 3.65 to 7.93MT/ha as planting density was decreased. Crude protein content increased from 9.8 to 14.5% ether extract comtent from 1.4 to 1.9%, nitrogen free extract content from 38.4% to 38.9% and TDN content from 45.4 to 50.9%, but crude fiber content decreased from 34.5 to 30.1% and crude ash content from 9.1 to 8.0% as planting density was decreased.

• Korean Journal of Agricultural Science
• /
• v.49 no.3
• /
• pp.561-570
• /
• 2022

This study investigated the changes in planting environment and growing conditions of 'Arisoo' apple trees under shading net treatments. Apple tree canopies were fully covered with Blue (blue color net, mesh size: 4 mm × 5 mm), Black-A (black color net, mesh size: 4 mm × 5 mm), Black-B (black color net, mesh size: 5 mm × 6 mm), and uncovered trees were used as the control. Inside the tree canopies, the illuminance was observed as 100% (85.0 Klux) in the control, but it decreased to 75% (64.3 Klux) in the Blue, 73% (63.0 Klux) in the Black-A, and 77% (65.9 Klux) in the Black-B nets, respectively. The solar irradiance was observed as 755 w·m^-3 in the control, but it was decreased to 715 w·m^-3 in the Blue, 624 w·m^-3 in the Black-A, and 647 w·m^-3 in the Black-B nets, respectively. The average daily temperature was observed to be the highest in the Black-A net (31.8℃) while it was observed to be around 30.0℃ in the control, Blue, and Black-B nets. In addition, the average fruit surface temperature was observed to be the highest (39.4℃) in the control, but it was decreased to 38.1℃ in the Blue, 37.3℃ in the Black-A, and 39.0℃ in the Black-B nets. However, the average soil temperature, the shoot growth rate, and leaf SPAD values were not different in all the treatments. Fruit sunburn disorders were the highest in the control while it was observed to be lower in the fruits from trees covered with the shading nets. However, at harvest, the fruit quality parameters were not different in all the treatments. Overall, this study suggests that the apple trees covered with the shading nets reduced the illuminance, solar irradiance, fruit surface temperature, and fruit sunburn disorders. However, the shading nets did not affect tree growth and apple fruit quality.

• Korean Journal of Agricultural Science
• /
• v.49 no.3
• /
• pp.643-653
• /
• 2022

This study investigated which nutrient solution is suitable for growth and secondary metabolite contents when three different vegetable plants are grown simultaneously in one hydroponic cultivation bed. Seeds of pak choi (Brassica compestris L. ssp chinsensis), red mustard (Brassica juncea L.), and arugula (Eruca sativa Mill.) were sown in the shape of a triangle in three places on rockwool cubes. The rockwool cubes were placed in semi deepflow technique (semi-DFT) hydroponic systems in a rooftop greenhouse after three weeks of growth as seedlings then cultivated with four different nutrient solutions, Korea Horticultural Experiment Station (KHE), Hoagland, Otsuka-A, and Yamazaki, at the rooftop greenhouse for two weeks. The leaf area of pak choi cultivated in Otsuka-A was the largest but SPAD values, leaf area, and fresh weight of arugula were highest with KHE treatment. The total glucosinolate (GSL) content of pak choi was 151.7% higher in KHE than in Hoagland, and there was no significant difference in Yamazaki and Otsuka-A treatments. The total GSL content of red mustard was 34.6 μmol·g^-1 in Hoagland, and it was 32.6% higher in Hoagland than in Yamazaki. Total GSL content of arugula was 57.5% higher in Yamazaki and Hoagland nutrients than in KHE and Otsuka-A nutrients solutions. The total GSL content of three plants grown with KHE was 40.7% higher than with Yamazaki, and the other nutrient solutions did not show significant differences. Therefore, KHE nutrient solution is considered suitable for nutrient solution composition for the cultivation of three different Brassicaceae crops in a single hydroponic cultivation system.

• Journal of Plant Biotechnology
• /
• v.50
• /
• pp.183-189
• /
• 2023

This study investigated the impact of two distinct MS basal media: one containing FeNaEDTA and the other FeEDDHA, on the growth of five unique gerbera cultivars (Shy Pink, Pink Holic, Breeze, Harmony, Snow Dream). Notably, the response to these media types varied significantly among the cultivars, particularly concerning leaf yellowing and plant growth. 'Shiny Pink' and 'Pink Holic' exhibited leaf yellowing on the FeNaEDTA-containing medium but displayed leaf greening on the FeEDDHA-containing medium. In contrast, 'Snow Dream,' 'Harmony,' and 'Breeze' remained unaffected on both medium types. However, the FeNaEDTA-containing medium promoted higher plant height and petiole length in 'Breeze,' 'Harmony,' and 'Snow Dream' than the FeNaEDTA-containing medium did. A promotive effect of silver nanoparticles (AgNPs) on plant growth and leaf greening was observed in 'Pink Holic,' particularly on the FeNaEDTA-containing medium, while the addition of AgNPs to the FeEDDHA-containing medium negatively affected plant growth. These results highlight the substantial influence of medium type, specifically the presence of FeNaEDTA or FeEDDHA, on gerbera growth responses, emphasizing the critical role of medium selection in gerbera propagation. Additionally, when contemplating the addition of AgNPs for in vitro gerbera propagation, it is crucial to consider the medium type.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.4
• /
• pp.468-476
• /
• 2020

This study was performed to establish light intensity conditions for producing stem cuttings for aeroponic systems suitable for seed potato production using a closed-type plant production system. Shoot tip cultured plantlets of 'Sumi' and 'Chubaek' potato (Solanum tuberosum L.) were acclimatized, cuttings were collected, and stem cuttings were planted. The seedlings were raised for 40 days at different LED light intensities (60, 120, 180, and 240 μmol·m^-2·s^-1), and were cultivated in an aeroponic system for 80 days. When stem cuttings were raised at 60 μmol·m^-2·s^-1 LED light intensity, the plant height was the longest, at 17.3 cm for 'Sumi' and 16.1 cm for 'Chubaek', and the number of nodes was the highest in both cultivars. The higher light intensities, produced smaller plants with fewer nodes. The leaf areas, SPAD values, and Fv/Fm values differed slightly between cultivars. The fresh weight of stem cuttings, and the production rate of healthy stem cuttings were the highest at 60 μmol·m^-2·s^-1. In the aeroponic system, seedlings raised at 60 μmol·m^-2·s^-1 with LED light intensity showed a difference between the cultivars, but the fresh weight of stems and leaves above the planting plate was the heaviest. In addition, below the planting plate the stem cuttings were longest and the root weight was heaviest at 60 μmol·m^-2·s^-1 LED light intensity. The number of stolons also differed between cultivars, but was greatest for seedlings raised at 60 μmol·m^-2·s^-1 LED light intensity, at 4.2/plant for 'Sumi' and 7.7/plant for 'Chubaek'. At 60 μmol·m^-2·s^-1 LED light intensity, the tuber number and total tuber weight were the best, but the higher the light intensity, the smaller the total tuber number and total tuber weight for both cultivars. In conclusion, when producing potato stem cuttings for aeroponic systems using a closed-type plant production system, the most suitable LED light intensity for raising seedlings was found to be 60 μmol·m^-2·s^-1.

• Journal of Biosystems Engineering
• /
• v.33 no.5
• /
• pp.362-369
• /
• 2008

There is developing interest in precision agriculture in Korea, despite the fact that typical Korean fields are less than 1 ha in size. Describing within-field variability in typical Korean production settings is a fundamental first step toward determining the size of management zones and the inter-relationships between limiting factors, for establishment of site-specific management strategies. Measurements of rice (Oriza Sativa L) yield, chlorophyll content, and soil properties were obtained in a small (100-m by 30-m) Korean rice paddy field. Yield data were manually collected on 10-m by 5-m grids (180 samples with 3 samples in each of 60 grid cells) and chlorophyll content was measured using a Minolta SPAD 502 in 2-m by 2-m grids. Soil samples were collected at 275 points to compare results from sampling at different scales. Ten soil properties important for rice production in Korea were determined through laboratory analyses. Variogram analysis and point kriging with and without median polishing were conducted to determine the variability of the measured parameters. Influence of variogram model selection and other parameters on the interpretation of the data was investigated. For many of the data, maximum values were greater than double the minimum values, indicating considerable spatial variability in the small paddy field, and large-scale spatial trends were present. When variograms were fit to the original data, the limits of spatial dependency for rice yield and SP AD reading were 11.5 m and 6.5 m, respectively, and after detrending the limits were reduced to 7.4 m and 3.9 m. The range of spatial dependency for soil properties was variable, with several having ranges as short as 2 m and others having ranges greater than 30 m. Kriged maps of the variables clearly showed the presence of both large-scale (trend) variability and small-scale variability in this small field where it would be reasonable to expect uniformity. These findings indicate the potential for applying the principles and technology of precision agriculture for Korean paddy fields. Additional research is needed to confirm the results with data from other fields and crops.d similar tendency with the result for the frequency less than 20 Hz, but the width of change was reduced highly.

• Journal of Bio-Environment Control
• /
• v.16 no.3
• /
• pp.240-246
• /
• 2007

To evaluated the effect of low temperature storage on quality of fresh shoot of Sedum sermentosum, weight loss, Hunter L, a and b value, chlorophyll, water content, and general appearance were investigated during storage at 20, 10, and $5^{\circ}C$. Just after harvesting, fresh shoots ($10{\pm}2cm$ length) were stored with wrap film (linear LDPE)-packaged condition using the Styrofoam dish ($20{\times}10cm$, which 40 fresh shoots per dish). The fresh weight of 40 shoots was gradually decreased according to days after storage and higher storage temperature. The weight loss of fresh shoots showed significant difference (8.7-25.3%) between just before storage and 10 days after storage, and the degree of weight loss was more severer in higher storage temperature. Wanju local strain showed the lowest weight loss, and the most severe case was Pohang local strain. SPAD value related to chlorophyll content was rapidly decreased after 4 and 6 days at 20 and $10^{\circ}C$ storage, respectively. It was slowly decreased according to days after storage at $5^{\circ}C$. Yellowish color in bottom leaves of shoot appeared after 4, 6 and 8 days at 20, 10, and $5^{\circ}C$ storages, respectively. Hunter L and a values were gradually increased after storage, and it showed significant difference between just before storage and 10 days after storage. The total rate of discoloration over 50% or decay shoot was largely increased as higher temperature. It was significantly correlated to the water content of fresh shoot among local strains $(P{\leq}0.01)$. The freshness of shoot after storage was maintained in order of Wanji, Gunsan, Wando and Pohang local strain. The results indicated that the freshness was maintained for 8 days after $5^{\circ}C$ storage, when the fresh shoot was stored with wrap film-packaged condition.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.27 no.4
• /
• pp.15-24
• /
• 2019

The study was compared for soil chemical and microbial properties as well as growth of the cherry tomato (Lycopersicon esculentum var. cerasiforme) plants environmentally friendly gown for 3 years and 5 years, which had been fertigated with homemade liquid fertilizer (LF) with indigenous microorganism as an additional fertilizer. Treatment included LF with indigenous microorganism for 3 years (3-year IM-LF) and for 5 years (5-year IM-LF), with an effective microorganism for 10 years (EM-LF), which had been applied with 1,000 times of dilution in the farmhouse. IM-LF and EM-LF materials had increased pH pattern for 16 weeks, in particular for increase of 1.2 for EM-LF. IM-LF material contained slightly higher EC but similar level of 0.2 dS/m to EM-LF. For a pot experiment in the greenhouse, IM-LF treatment increased root dry weight of the cherry tomato plants. In the farmhouse experiment, IM-LF treatment increased to 7.5 of soil pH and 8.4 dS/m of EC, indicating high salt accumulation. EM-LF treatment increased to 62 g/kg of soil OM, which would have affected concentrations of macro essential nutrients, including T-N in the soil. However, the optimum soil chemical levels for growth of cherry tomato plants were observed on the IM-LF plots. EM-LF treatment increased number of bacteria and actinobacteria in the soil. EM-LF treatment increased concentrations of macro essential nutrients in the plants, except for P, with similar nutrient concentrations observed between 3-year IM-LF and 5-year IM-LF-treated plants. Leaf SPAD and PS II levels decreased in the plants treated with 3-year IM-LF. EM-LF treatment increased leaf width and length, number of leaves, canopy area, plant height, and stem diameter in the mid-term stage of growth, which were not significantly different between the treatments. EM-LF treated-plants had two times higher leaf dry weight than those of values observed on the IM-LF plants, which was the opposite result observed on the number of fruit.