• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.365-371
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• 2007

Objective of this research was to investigate the effect of nitrogen concentrations in the fertilizer solution on growth and development of nutrient deficiency in leaf perilla (Perilla frutesens). The nutrient concentrations in above-ground plant tissue, petiole sap and soil solution of root media were also determined. Nitrogen deficiency resulted in dwarfed growth, small leaves, and bright yellow color of older leaves. The leaves of deficient plants became uniform yellowing in color and finally necrosis occurred on the deficient leaves. Elevation of N concentrations in the fertigation solution from 0 to 20 mM increased the crop growth in leaf length and width as well as fresh and dry weights of above ground plant tissue. That also resulted in the increase of chlorophyll contents. However, light toxicity symptoms such as abnormal leaf surface appeared on crops grown in 20 mM N fertilization. The plant growth was commercially acceptable in the treatments of 10 and 15 mM N. The plants with acceptable growth had 0.9 to 1.25% in N contents of above-ground plant tissue, 800 to $3,300mg{\cdot}kg^{-1}$ in the $NO_3-N$ concentrations of petiole sap, and 28.7 to $47.3mg{\cdot}kg^{-1}$ in the $NO_3-N$ concentrations of soil solution (1:2 extract) at 75 days after transplanting.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.352-357
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• 2007

We investigated effects of concentration and duration were investigated in order to promote efficiency of $CO_2$ enrichment in winter. The treatments were conducted with two levels of $CO_2$ concentration, namely 400 ppm, 700 ppm, two levels of duration, 3 h (9:00-12:00), 6 h (9:00-15:00), and control (nonenrichment $CO_2$). Fresh weight of leaves increased under longer exposure to $CO_2$ and higher $CO_2$ concentration. Fresh weight of stem and root increased under longer exposure to $CO_2$, but decreased under higher $CO_2$ concentration. Total dry weight increased under longer exposure to $CO_2$ and higher $CO_2$ concentration. Combination treatment of longer exposure to $CO_2$ and higher $CO_2$ concentration showed the largest decrease of Root : Shoot dry weight ratio. The $700ppm{\times}6h$ treatment showed higher fruit number and yield than control. The results suggested that the growth under longer exposure to 400 ppm $CO_2$ was better than that under higher $CO_2$ concentration.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.1
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• pp.1-6
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• 2005

With recent interest organic farming the use of legumes including vetch and clover to provide N to adjacent crops is increasing in Korea. In the present studies, we conducted a trial to investigate the effects of the application of N rate on nitrogen fixation and transfer from vetch to barley in mixed stands. The experiment was arranged in a randomized complete block design with three replications. Four different N rates(0, 75, 113 and 150/ha) was used and vetch+barley was broadcasted manually on 1.5 $\times$2 m plot in Oct. 2001. Half of urea and K$_{2}O, 200 Phosphate and 75 kg potash per ha were applied as basal dressing md half of N md 75 potash were used for topdressing to soil surface on MarctL 2002. The equivalent of 1kg ha$^{-1}$ at($^{15}$NH$_{4}$)$_{2}$SO$_{4}$ solution at 99.8 atom $\%$$^{15}$N excess was applied to the microplot in mid April. Forage was harvested from each plot at ground level and separated into barley and vetch. Total N content and It values of samples were determined using a continuous flow stable isotope ratio mass spectrometry(IsoPrime-EA. Micromass, UK.). The percentage of legume H fixed from atmospheric N2 were 95.0, 93.8, 94.4 and $84.8\%$ with increment of N levels. The percentage of N transfer from vetch to barley by N-difference method with increment of N fertilizer were from 58 to$49\%$ while 39 to $23\%$ in $^{15}$N-dilution method. The amount of transfer from vetch to barley were 87 to 68 kg/ ha with N level by N-difference moth여 and 58 to -56/ha with N application levels by $^{15}$N dilution method. The amount of nitrogen fixation per ha were from 150 kg / ha to 219 kg / ha by different method, but on the other side 49 to 105kg/ha by N$^{15}$-dilution.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.357-364
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• 2011

Proper light intensity, potting media, fertilization level, and shade tolerance were investigated to develop Orostachys (Korean name, Nungyu bawisol) as a potted ornamental plant. The best plant growth was shown at 52% shading. Although plant growth decreased at 82% shading, ornamental value maintained at that shading rate, which indicate that O. 'Nungyu bawisol' has high shading tolerance. At over 90% shading, some of the plants died and showed decolorization and standing erect in leaves, resulting in a big decrease in ornamental value. Potting medium of decomposed granite (DG) : fertilizer-amended media (FAM) : river sand (RS) (6 : 2 : 2, v/v/v) showed the best growth in potted O. 'Nungyu bawisol'. Fresh weight of shoot part was 16 g in DG : FAM : RS (6 : 2 : 2, v/v/v), which was over 2 folds of those at the other medium. Drenching of Hyponex solution diluted by 1,000~2,000 folds 1 time per week brought the highest results in fresh weight, plant width, and runner number. Particularly, fresh weight of shoot part was 13 g higher than that of control (16 g). Leaf color tended to be darkened as concentration of Hyponex solution increased.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.328-335
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• 2023

For appropriate nutrient management and enhanced plant growth, soil sensors which reflect soil nutrient levels are required. Because there is no available sensor for nutrient monitoring, electrical conductivity (EC) sensor can be used to evaluate soil nutrient levels. Soil nutrient management using EC sensors would be possible by understanding the relationship between sensor EC values and soil temperature, moisture, and nutrient content. However, the relationship between soil sensor EC values and plant available nutrients was not investigated. Therefore, the objectives of the study were to evaluate effect of different amount of urea on soil EC monitored by sensors during pepper and broccoli cultivation and to predict the plant available nutrient contents in soil. During the cultivation period, soil was collected periodically for analyzing pH and EC, and the available nutrient contents. The sensor EC value increased as the moisture content increased, and low fertilizer treated soil showed the lowest EC value. Principal component analysis was performed to determine the relationship between sensor EC and available nutrients in soil. Sensor EC showed a strong positive correlation with nitrate nitrogen and available Ca. In addition, sum of available nutrients such as Ca, Mg, K, P, S and N was positively related to the sensor EC values. Therefore, EC sensors in open field can be used to predict plant available nutrient levels for proper management of the soil.

• Korean Journal of Organic Agriculture
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• v.28 no.3
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• pp.417-430
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• 2020

Drought stress is one of major environmental stresses in plants; this leads to reduce plant growth and crop yield. In this study, we selected fungal isolate for mitigating drought stress in pepper plants. To do this, 41 fungi were isolated from rhizosphere or bulk soils of various plants in Jeju, Gangneung, Hampyeong in Korea. Out of 41 isolates, we screened two isolates without phytotoxicity through seed germination of tomato, pepper, and cabbage treated with fungal spores; through following plant assay, we selected GL02 as a candidate for alleviating drought stress in pepper plants. As a result of greenhouse test of pepper plants in drought condition, the stomatal conductance on leaves of pepper plants treated with GL02 was increased, whereras the malondialdehyde (MDA) and electrolyte leakage were decreased compared to that in control plants. When stressed plants were rewatered, stomatal conductance of the plants treated with GL02 was increased; the electrolyte leakage was decreased. Based on internal transcribed spacer (ITS) sequencing analysis, isolate GL02 was belonging to genus Trichoderma. Taken together, drought stress in pepper plants treated with GL02 was alleviated, when it was rewatered after drought-stressed, the plants could be recovered effectively. Therefore, Trichoderma sp. GL02 could be used as a bio-fertilizer to alleviate drought stress in pepper plants.

• Journal of Applied Biological Chemistry
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• v.54 no.4
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• pp.290-295
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• 2011

This study was carried out to investigate the quality of soil, irrigation water, and status of agrochemicals application in relation to good agriculture practices system in the major cultivation area of Disocorea batatas. The concentrations of heavy metals as Cd, Pb, Cu, and Zn in soils and irrigation waters were lower than those of standard level for Environmental Conservation Act of Soil and Water in Korea. The dominant weed have been appeared Digitaria sanguinalis and Portulaca oleraceamite. The dominant insect pests and plant pathogens have been appeared aphid and anthracnose. Average yearly application of pesticide was 2 to 4 times for herbicide and 4 to 6 times for plant pathogens and insect pests. In order to safety production of medicinal crops could be achieved by proper cultivation management such as minimum application of agro-chemicals, effective use of by-product fertilizer, and technology development of organic farming.

• Journal of Microbiology and Biotechnology
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• v.30 no.10
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• pp.1500-1509
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• 2020

Drought is a major abiotic factor and has drastically reduced crop yield globally, thus damaging the agricultural industry. Drought stress decreases crop productivity by negatively affecting crop morphological, physiological, and biochemical factors. The use of drought tolerant bacteria improves agricultural productivity by counteracting the negative effects of drought stress on crops. In this study, we isolated bacteria from the rhizosphere of broccoli field located in Daehaw-myeon, Republic of Korea. Sixty bacterial isolates were screened for their growth-promoting capacity, in vitro abscisic acid (ABA), and sugar production activities. Among these, bacterial isolates YNA59 was selected based on their plant growth-promoting bacteria traits, ABA, and sugar production activities. Isolate YNA59 highly tolerated oxidative stress, including hydrogen peroxide (H₂O₂) and produces superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities in the culture broth. YNA59 treatment on broccoli significantly enhanced plant growth attributes, chlorophyll content, and moisture content under drought stress conditions. Under drought stress, the endogenous levels of ABA, jasmonic acid (JA), and salicylic acid (SA) increased; however, inoculation of YNA59 markedly reduced ABA (877 ± 22 ng/g) and JA (169.36 ± 20.74 ng/g) content, while it enhanced SA levels (176.55 ± 9.58 ng/g). Antioxidant analysis showed that the bacterial isolate YNA59 inoculated into broccoli plants contained significantly higher levels of SOD, CAT, and APX, with a decrease in GPX levels. The bacterial isolate YNA59 was therefore identified as Variovorax sp. YNA59. Our current findings suggest that newly isolated drought tolerant rhizospheric Variovorax sp. YNA59 is a useful stress-evading rhizobacterium that improved drought-stress tolerance of broccoli and could be used as a bio-fertilizer under drought conditions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.173-179
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• 2017

Advanced countries, animal wastes are produced using bioenergy and methane gas technology. In Korea, many researches are being actively carried out to develop livestock manure as a resource technology rather than a animal waste. However, the production of bio-gas using livestock manure is still in the process of development of functional livestock and compost because of low economic efficiency with livestock manure recycling technology. In this paper, in order to accurately estimate the manure output, It will calculate the manure excretion if you have finished input the number of pigs. In addition, we simulated the fertilization rate of three elements of NPK fertilizer per 100 square meters automatically.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.123-132
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• 2018

The purpose of this study was to evaluate the reduction effect of non point source (NPS) pollution in Haean highland agricultural catchment ($62.8km^2$) for 13 BMP scenarios under RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios. Under the present climate condition, the BMP (best management practices) reduction efficiency of SS (suspended solid), T-N (total nitrogen), and T-P (total phosphorus) showed +25.7%, +4.2%, and +16.1% for VFS (vegetative filter strip), +0.1%, +15.6%, and +5.7% for FC (fertilizer control), and +6.3%, -2.9%, and +3.9% for RSM (rice straw mulching) respectively. In general, effective was the best for SS and T-P reductions, and the FC was the best for T-N reduction. The negative effect of T-N on RSM was induced by increase in infiltration and solute transport to baseflow. Under the future climate change scenarios, the SS, T-N, and T-P reduction efficiency showed the range of +1.9~+11.6%, -1.9~+0.2%, and +5.3~+11.9% respectively. The 3 BMPs (VFS, FC, and RSM) application in the future showed negative and little differences (-0.5~+1.6%) for SS and T-N reduction efficiencies while T-P reduction efficiency showed +0.3~+7.6% comparing with the baseline period. To achieve an increase in the reduction efficiency of future SS and T-N by +2~+10%, the combined application of more than two BMPs is necessary.