Yong-Han Yoon

Effect of Calcium Chloride Concentration on Roadside Ground Cover Plant Growth

The purpose of this study was to provide information on management and apply it to a roadside ground cover plant understanding the capacity of calcium chloride in the plant. The experimental group was composed of the ratio control group of calcium chloride, 0.5%, 1.0%, and 3.0% in 500g of soil. Plant materials were selected and measured according to their ecological characteristics such as ground cover plant, Pachysandra terminalis, Hosta plantaginea, Trachelospermum asiaticum, Vitex rotundifolia, Euonymus japonica and Callicarpa japonica. The acidity of the amended soil was increased gradually depending on the treatment and conductivity was continually decreased. The EX-Ca increased after the treatment, but decreased in the middle of the experiment. Pachysandra terminalis, Trachelospermum asiaticum and Euonymus japonica were able to grow and survive at the ratio of 0.5%. Hosta plantaginea and Vitex rotundifolia were able to survive at the ratio of 1.0%. Hosta plantaginea, the possible state can absorb salts due to moisture and, can be applied to ground cover plants in the roadside. The growth and development of Callicarpa japonica was poor and the leaves were open to grow for calcium chloride treatment except the control group. It was concluded that Callicarpa japonica was very sensitive to calcium chloride.

A Study on the Actual Condition of Topsoil Management at River Restoration Projects

This study aimed to research and analyze the real condition of topsoil management of river development field as a significant case among domestic development fields for topsoil preservation. Through survey with experts, we understood the real condition and problems of topsoil management during river development. In order to verify this, we analyzed the characteristics of soil before and after development focusing on the rivers recently completed as an ecological river restoration project, supervised by Ministry of Environment among domestic river improvement projects. The study results are like below. First, experts preferred collecting and reusing topsoil as the best method to maintain and improve soil for plant growth. Second, realistically collecting and reusing topsoil is not fully conducted due to economical issues and inconvenience in construction. In the soil condition, third, the contents of elements necessary for plant growth like organic matter and total nitrogen declined overall after development.

Boron availability alters its distribution in plant parts of tomato

This study was performed to investigate boron (B) distribution within various parts of tomato plants (Solanum lycopersicum L. ‘Super Momotarou’) grown under either B supply (adequate, 0.5 mg·L−1) or no B (0 mg·L−1) condition. The objective was to examine how B supply affects plant growth, photosynthetic activity and the morphological response of the entire root system. When the plants were grown for 36 days under the B supply treatment, B concentration was greatest in the order of the leaf (54.3 μg·g−1), fruit cluster (27.8 μg·g−1), petiole (24.7 μg·g−1), and stem (14.1 μg·g−1). However, B deficient supply altered the B distribution so that the greatest concentration was found in the stem (7.82 μg·g−1); then the petiole (8.20 μg·g−1), the fruit cluster (5.5 μg·g−1), and lastly in the leaf (4.11 μg·g−1). No B treatment resulted an approximately 46% decrease in the calcium content of the leaf and an 87% decrease in the potassium content of the fruit cluster. No B treatment also led to a severe decrease in photosynthetic rate, stomatal conductance and transpiration, with an increase in the water vapor saturation deficit at the leaf surface. Microscopic investigation of the stomata 36 days after transplant revealed that a majority of the stomata in the epidermal layer of B-deficit leaves were closing. The total dry weights of the leaves, leaf petioles and stems of B-deficit leaves decreased by 36, 43, and 27%, respectively, at 22 days after transplant, and decreased by 60, 69, and 60%, respectively, at 36 days after transplant, compared to the values for the B-sufficient leaves. A 10-fold lower fruit cluster dry weight was also observed in the B-deficit plants. Under no B supply, the total root length at 35 days after transplant decreased by about 56%, while the average root diameter increased by 20%. This was associated with a significant decrease in the root length, which ranged between 0 and 0.2 mm in diameter, alongside a significant increase in the root length, which ranged larger than 0.9 mm in diameter. One explanation for this finding is that limited B availability leads to a lack of translocation of B to the leaf and reproductive tissues, and this alteration of B partitioning may then affect fruit quality as well as root growth. An improved understanding of B partitioning in plant tissues may help to improve B management and, in the long term, improve crop yields.

Change in Growth of Chrysanthemum zawadskii var. coreanum as Effected by Different Green Roof System under Rainfed Conditions

This study aims to suggest a suitable soil thickness and soil mixture ratio of a green roof system by verifying the growth of Chrysanthemum zawadskii var. coreanum as affected by different green roof systems using rainwater. The experimental planting grounds were made with different soil thicknesses(15cm, 25cm) and soil mixing ratios (SL, , , , ) and with excellent drought tolerance. Ornamental value Chrysanthemum zawadskii var. coreanum was planted. The change in plant height, green coverage ratio, chlorophyll content, fresh weight, dry weight, and dry T/R ratio of Chrysanthemum zawadskii var. coreanum were investigated from April to October 2009. For 15cm soil thickness, the plant height of Chrysanthemum zawadskii var. coreanum was not significantly different as affected by the soil mixing ratio. However, it was found to be higher in the amended soil mixture, , , and than in the sandy loam soil, as it was SL overall. For 25cm soil the plant height differences were in order to SL , , . The green coverage ratio was observed not to be different by soil mixing ratio with soil thickness of 15cm, but, the lowest green coverage ratio in the SL. In the 25cm soil thickness, the green coverage ratio was 86-89% with a good coverage rate overall. The change in chlorophyll contents with 15cm soil thickness was found to be the highest in the SL treatment and the lowest in the treatment. For 25cm thickness, the highest value was in the and SL, and the lowest in the. Fresh weight and dry weight were larger in soil with 25cm thickness. Therefore, the growth of Chrysanthemum zawadskii var. coreanum as affected by a different green roof system for using rainwater was higher in soil with 25cm thickness than 15cm, and in PPL amended soil than in sandy loam.

Erratum to: Environmentally sustainable production of tomato in a coir substrate hydroponic system using a frequency domain reflectometry sensor

Open hydroponic systems are the most widely used hydroponic systems in Korea. However, water drainage from the open hydroponics often causes significant environmental pollution due to agrochemicals and loss of water and nutrients. The objectives of this study were to show the potential application of an irrigation schedule based on threshold values of volumetric substrate water content tomato (Solanum lycopersicum L. ‘Betatini’) cultivation in a commercial hydroponic farm. This study was performed for minimizing effluent from coir substrate hydroponics using a frequency domain reflectometry (FDR) sensor-automated irrigation (FAI), as compared with conventional timer-irrigation (TIMER) from the farmer’s experience. The irrigation volume and retained water volume in the substrate of the TIMER during autumn to winter cultivation were 6.1-fold and 2-fold higher, respectively, than those of the FAI with slightly higher fruit weight and no difference in plant growth in the TIMER. This resulted in 1.9-fold higher water use efficiency (WUE) in the FAI. The irrigation volume and retained water volume in the substrate of TIMER during spring to summer were 3.2-fold and 1.8-fold higher, respectively, than those of the FAI with no difference in fruit weight or plant growth between the two treatments, which led to a 1.9-fold higher WUE in FAI. Approximately 61% fertilizer cost savings and a substantial decrease in drained solution volume were observed for FAI compared to those with TIMER. The use of the FAI technique for a least-drainage hydroponic system can be achieved in a large-scale hydroponic farm, resulting in efficient and environmentally sustainable use of water and fertilizer. Additional key words: leachate, retained water volume, volumetric water content, water use efficiency Hort. Environ. Biotechnol. 56(2):167-177. 2015. DOI 10.1007/s13580-015-0036-y ISSN (print) : 2211-3452 ISSN (online) : 2211-3460