• The Korean Journal of Mycology
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• v.28 no.2
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• pp.93-96
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• 2000

To investigate the effect of inorganic nutrient supplement in oyster mushroom (Pleurotus ostreatus), we have conducted some study on cultural and growth characteristics of fruitbody formation and chemical composition of media and fruitbody. When supplemented with slow releasing fertilizer, contamination rate was not different from non-supplemented medium, days for incubation time and first pinhead were faster than non supplemented medium. And fruitbody yield and biological efficiency were increased $10{\sim}28%,\;7{\sim}20%$ respectively, but biological efficiency was decreased when increased supplement ratio. The chemical compositions (total carbon, total nitrogen, ammonia nitrogen, nitrate nitrogen, potassium and phosphate) of slow releasing fertilizer supple mented medium and fruitbody were compared with non-supplemented.

• Journal of Applied Biological Chemistry
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• v.42 no.4
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• pp.186-190
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• 1999

Isotope ratio ($^{15}N/^{14}N$) and nitrate-nitrogen concentration in groundwater were measured to investigate the effect of chemical fertilizer and livestock manure on temporal variations in nitrate-nitrogen concentration and to estimate the contribution of fertilizer and manure to groundwater contamination by nitrate. Four study wells from a rural area in Kyonggi province were selected. One well was located on an upper site from a livestock feedlot, and the others were situated at lower sites from the feedlot. The ${\delta}^{15}N$ values were analyzed by a stable isotope ratio mass spectrometer (Micromass, VG Optima IRMS). Reproducibility of the method and precision of the mass spectrometer were below 1.0 and 0.1‰, respectively Even though study wells were located at the same area, nitrate-nitrogen concentrations and ${\delta}^{15}N$ values differed and fluctuated during the sampling period. The ${\delta}^{15}N$ values of well located at upper site from the feedlot were extremely variable (-1.48~20.80‰). The ranges of ${\delta}^{15}N$ value of three wells situated at lower sites from the feedlot were 11.83~20.73 (ave. 16.11), 8.90~11.73 (ave.11.01), and 5.29~12.73‰ (ave. 8.21‰) with increasing distance from the feedlot. The average values of contribution proportion of nitrogen derived from livestock manure to nitrate-nitrogen in groundwater were 79% for the well closet to the feedlot, 44% for the well most distant from the feedlot, and 56% for the well in between the two wells.

• Applied Biological Chemistry
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• v.49 no.3
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• pp.175-179
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• 2006

This study was carried out to investigate the change of rhizosphere microflora in paddy soils of long-term application of same fertilizer by single cropping. Treatments consisted of no fertilizer, NPK, PK, NK, NP and NPK + compost and the same fertilizer has been applied to the soil of each treatment for thirty five years. Any remarkable difference of the microbial population structure was not detected from the rhizosphere of Hwayeongbyeo and that of Hwasambyeo. However, slight difference of dominant microbial species in the rhizosphere was recognized between different fertilization practice. The bacterial population in the rhizosphere was steadily reduced over time after rice plant setting out, while actinomycetal population was increased over time. The increase of actinomycetal population was the highest in the NPK + compost treatment, suggesting the effect of organic matters in the change of actinomycetal population. As for the aerobic culturable bacterial diversity, Bacillus megaterium, B. mycoides, B. licheniformis and B. subtilis were dominants in genus Bacillus, and Streptomyces spororaveus, S. canus, S. tauricus and S. galbus in genus Streptomyces and genus Micromonospora was another dominant in actinomycetes.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1017-1021
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• 2012

A field experiment was conducted to evaluate effect of water soluble silicate fertilizer (WSS) application on rice plants with respect to comparing with powdery slag-originated silicate fertilizer (PSS) and granular one (GSS). The 30-day seedlings were transplanted on May 10, 2012. The plot size was $25m^2$, and the planting density was 15 hills $m^{-2}$. The standard application level was $2kg\;ha^{-1}$ for WSS, $200kg\;ha^{-1}$ for GSS, $200kg\;ha^{-1}$ for GSS. The application rates were 50 %, 100 %, and 200 % of the standard levels. The soil and plant samples were taken after harvest on September 10. Strength weight of the stem was measured on the center of the 5-cm of the fourth internode. Nutrient contents and yield of grains and were evaluated. The strength weight of the stem was positively correlated with the silicate content of the stem with the highly significant $R^2$ of 0.601. The strength of the stem was satisfactorily enforced by application of 50 % WSS and GSS, and 100 % PSS. Application of 50 % or 100 % of WSS showed little difference in rice yield in comparison with application of 100 % of PSS or GSS. Therefore, application of $20kg\;ha^{-1}$ of WSS would be recommendable for rice cultivation which enforced stem strength, and increased yield of rice.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.598-607
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• 2016

This study was conducted to evaluate the amount of nitrogen (N) top dressing based on the normalized difference vegetation indices (NDVI) by ground based sensors for leaf perilla under the polyethylene house. Experimental design was the randomized complete block design for five N fertilization levels and conventional fertilization with 3 and 4 replications in Gumsan-gun and Milyang-si field, respectively. Dry weight (DW), concentration of N, and amount of N uptake by leaf perilla as well as NDVIs from sensors were measured monthly. Difference of growth characteristics among treatments in Gumsan field was wider than Milyang. SPAD-502 chlorophyll meter reading explained 43.4% of the variability in N content of leaves in Gumsan field at $150^{th}$ day after seedling (DAS) and 45.9% in Milyang at $239^{th}$ DAS. Indexes of red sensor (RNDVI) and amber sensor (ANDVI) at $172^{th}$ day after seedling (DAS) in Gumsan explained 50% and 57% of the variability in N content of leaves. RNDVI and ANDVI at $31^{th}$ DAS in Milyang explained 60% and 65% of the variability in DW of leaves. Based on the relationship between ANDVI and N application rate, ANDVI at $172^{th}$ DAS in Gumsan explained 57% of the variability in N application rate but non significant relationship in Milyang field. Average sufficiency index (SI) calculated from ratio of each measurement index per maximum index of ANDVI at $172^{th}$ DAS in Gumsan explained 73% of the variability in N application rate. Although the relationship between NDVIs and growth characteristics was various upon growing season, SI by NDVIs of ground based remote sensors at top dressing season was thought to be useful index for recommendation of N top dressing rate of leaf perilla.

• Journal of Life Science
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• v.29 no.10
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• pp.1055-1061
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• 2019

Sarracenia purpurea as a carnivorous plant in the family Sarraceniaceae is known to require strong light for its growth and to absorb nutrients from the decomposed molecules of insects that are attracted by color, sweet juice, and the like. S. purpurea grew greenish in whole body under weak light conditions, while the whole of the insectivorous sac including leaves, is changed to dark red under strong light conditions. The phenomenon of reddish S. purpurea is thought to be related to the flavonoid pigment anthocyanin. Interestingly, the color change was not observed when S. purpurea was grown in a growth condition with abundant nitrogen fertilizer. The expression levels of anthocyanin contents and biosynthesis-related genes were strongly correlated with light intensity and nitrogen fertilizer. The anthocyanin content in the strong light condition ($240{\mu}mol\;m^{-2}s^{-1}$) was 6.15 times higher than that in the weak light ($40{\mu}mol\;m^{-2}s^{-1}$). In contrast, the anthocyanin contents were not significantly changed when 0.8% urea solution was supplied as nitrogen fertilizer. Consistently, CHALCONE SYNTHASE (CHS) gene was up-regulated by strong light and down-regulated by nitrogen fertilizer. These results suggest that the environmental changes of light and nitrogen in soil regulate the anthocyanin content in S. purpurea.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1016-1022
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• 2011

Application of silicate fertilizers is typically practiced with several year's interval to amend soil quality and improve rice productivity at the paddy field in Korea. Most of silicate fertilizers applied in Korea is slag-originated silicate fertilizer. Some water soluble silicate fertilizers are manufactured and commercially available. The objective of this study was to assess changes of soil chemical properties in paddy field by applying slag-originated silicate fertilizer and water soluble silicate fertilizer. Field experiment was conducted on a silt loam paddy soil, where four levels of each silicate fertilizer were applied in soil at the rate of 0, 1, 2, 4 times of the recommended levels. Application of slag-originated silicate fertilizer increased soil pH, while no significant pH increase occurred with the treatment of water soluble silicate fertilizers. Soil pH increased 0.4~0.5 with the 1 time of recommended level of slag-originated silicate fertilizer. Available $SiO_2$ contents also significantly increased with the treatment of slag-originated silicate fertilizer at 15 and 35 days after treatment, while decreased after 60 days after treatment possibly due to rice uptake. Exchangeable Ca, Mg and available phosphate contents in soil increased with application of slag-originated silicate fertilizer, while a little increases for them were shown with the application of soluble silicate fertilizer. $SiO_2$/N ratios in rice straw for 1 time of recommended level of slag-originated silicate fertilizer was 11.5, while that of control was 8.4, which was much lower value. Throughout this study, soil application of slag-originated silicate fertilizer enhanced soil chemical properties, while water soluble silicate fertilizer application in soil needs further study resulting in a little effects on soil property.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.1-8
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• 2012

The thermal properties including volumetric heat capacity, thermal conductivity, thermal diffusivity, and diurnal and annual damping depths of 10 representative soil series of Korea were calculated using some measurable soil parameters based on the Taxonomical Classification of Korean Soils. The heat capacity of soils demonstrated a linear function of water content and ranged from 0.2 to $0.8cal\;cm^{-3}^{\circ}C^{-1}$ for dry and saturated medium-textured soil, respectively. A small increase in water content of the dry soils caused a sharp increase in thermal conductivity. Upon further increases in water content, the conductivity increased ever more gradually and reached to a maximum value at saturation. The transition from low to high thermal conductivity occurred at low water content in the soils with coarse texture, and at high water content in the other textures. Thermal conductivity ranged between $0.37{\times}10^{-3}cal\;cm^{-1}s^{-1}^{\circ}C^{-1}$ for dry (medium-textured) soil and $4.01{\times}10^{-3}cal\;cm^{-1}s^{-1}^{\circ}C^{-1}$ for saturated (medium/coarse-textured) soil. The thermal diffusivity initially increased rapidly with small increases in water content of the soils, and then decreased upon further increases in the soil-water content. Even in an extreme soil with the highest diffusivity value ($1.1{\times}10^{-2}cm^2s^{-1}$), the daily temperature variation did not penetrate below 70 cm soil depth and the yearly variation not below 13.4 m as four times of damping depths.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.572-581
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• 2012

In this study, we compared growth pattern, floc yield, Exo-polysaccharides (EPS) production, Poly-${\beta}$-hydroxybutyrate (PHB) accumulation, resistance to osmotic and acid stress in Methylobacterium strains CBMB20, CBMB27, CBMB35, and CBMB110. Modified high C:N ratio medium denoted as HCN-AMS medium was used with a C:N ratio of 30:1. The HCN-AMS medium favored increased growth in all the studied strains. All Methylobacterium strains tested positive for EPS production and showed positive fluorescence with calcoflour stain. Elevated levels of EPS production from 4.2 to 75.0% was observed in HCN-AMS medium. Accumulation of PHB in HCN-AMS medium increased by 3.8, 36.7, and 12.0% in strains CBMB27, CBMB35, and CBMB110 respectively. Among the abiotic stresses, osmotic stress-induced growth inhibition of Methylobacterium strains was found to be lowered when grown in HCN-AMS medium. Likewise, growth inhibition due to acid stress at pH 5.0 was lower for strains grown in HCN-AMS medium compared to growth in AMS medium. Enhanced survivability under stress conditions may be attributed to the high EPS and PHB production at increased carbon concentration in the growth medium.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.650-656
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• 2011

Lysobacter antibioticus HS124 isolated from pepper rhizosphere soil produced catechol type siderophore. Purified siderophore by Diaion HP-20 and silica gel column chromatography showed several hydroxyl functional groups adjacent to benzene rings by analysis of $^1H$ NMR spectroscopy. The strain HS124 showed different activities to suppress Phytophthora capsici with different concentrations of exogenous Fe (III) in minimal medium where antifungal activity with $100{\mu}M$ Fe (III) was approximately 1.5 times higher than in absence of Fe (III). Bacterial population in this Fe (III)-amended medium was also highest with $8.9{\times}10^8\;CFU\;ml^{-1}$ which also corresponded to the strongest siderophore activity. When grown in rich medium (minimal medium with N, $P_2O_5K_2O$ and glucose), HS124 exhibited approximately 2 times stronger antifungal activity compared to minimal medium. In pot trials, treatments of bacterial culture grown in rich medium with (C1) or without (C2) $100{\mu}M$ Fe (III) exhibited a high protection of pepper plants from disease, compared to medium only with (M1) or without (M2) $100{\mu}M$ Fe (III). Especially, treatment C1 showed the best disease control effect of about 70 %. Thus, the strain HS124 should be recommended as a potential biocontrol agent against P. capsici in pepper.