• Korean Journal of Soil Science and Fertilizer
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• v.24 no.4
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• pp.260-264
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• 1991

To investigate the proper fertilization position in the soil accumulated with phosphorus and salt, tomato, Seo-Kwang, was planted on the bottomless pot, 45cm diameter 30cm length, filled with three different soils ranged 567 to 1,140 ppm of available phosphorus (0.45~3.69 mmhos/cm in electrical conductivity). Fertilizer phosphorus was treated at three different sites of side 0~5,6~10, 11~15cm and three different sites of depth; 0~5, 6~10, 11~15cm, The results are follows; Fertilizer use efficiency (FUE) of phosphrous of tomato was decreased as avilable phosphorus in soil increased. Highest FOE of phosphorus was showed at band application of feliilizer phosphorus at 0~5cm side and 11~15cm depth in the soil contain ing 567ppm of available phosphorus, and 6~10cm side and 0~5cm depth in the soils containing 942 and 1,140ppm of phosphorus. At 45 days after planting tomato root was highly distribued to 0~5cm side and depth respectively in low salt soil (0.45mmhos/cm), 11~15cm depth in 2.61mmhos/cm soil and 6~10cm depth in 3.69mmhos/cm. The fertilizer use efficiency of phosphorus of tomato plant war negatively significantly correlated with soil EC and phosphate concentration at 45 days after planting. The fertilizer use efficiency of phosphorus was more highly correlated with available phosphorus than electrical conductivity in soil.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.963-969
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• 2011

The river-bed sediments from the major river basins were analysed for the chemical and physical properties to evaluate environmental safety for the agricultural uses. The samples were taken from 16 sites of Han river, 36 of Geumgang river, 27 of Yeongsan river, and 140 of Nakdong river. The total of 219 samples from the 28 counties were taken from the surface of the sediments at the depth of 50 cm. The particle density of the sediments was greater than $2.63Mg\;m^{-3}$ and the whole range of the density was $2.60{\sim}2.69Mg\;m^{-3}$, the average particle size was 0.7 mm whereas the size range was 0.075~0.85 mm. The analyses of the particle sizes by basins showed that Han and Geumgang river had particle sizes of 0.075~0.85 mm, while Geumgang and Yeongsan river had particle sizes of 0.25~0.85 mm. Geumgang and Yeongsan river tended to have greater particle sizes. The average values of the chemical properties were 6.3 for pH, $0.16dS\;m^{-1}$ for EC, $8g\;kg^{-1}$ for organic matter, $101mg\;kg^{-1}$ for available phosphate, 0.39, 3.47, and $0.93cmol_c\;kg^{-1}$ for exchangeable potassium, calcium, and magnesium respectively. The greatest property at each basin was pH for Han river, Ec, available phosphate and exchangeable sodium for Geumgang river, organic matter, exchangeable calcium and magnesium for Yeongsan river, and exchangeable potassium for Nakdong river.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.273-280
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• 2019

BACKGROUND: The reclaimed lands for agricultural use managed by the Korean government is consisted of 17,145 hectares of lands under construction and 13,384 hectares of completed lands. In order to utilize these reclaimed lands as competitive agricultural complexes, the government is preparing to develop comprehensive development plans for multiple purposes. For rational land-use planning and soil management, information of the soil chemical properties is necessary. METHODS AND RESULTS: From 2013 to 2016, soil samples were collected from 85 representative sampling sites of the reclaimed lands and analyzed for soil chemical properties including electric conductivity (EC), pH, soil organic matter (SOM), and nutrients. The annual mean soil EC ranged from 5.1 to 8.3 dS m^-1 and have continued to decrease over the years (estimation equation with EC as dependent and year as independent variable was y =0.0736x² - 1.4985x + 9.8305, R² = 0.9753). The pH ranged from 7.3 to 7.6, which was higher than the optimum range (5.5~7.0) for agricultural soils. Soil organic matter (8 to 11 g kg^-1) was lower level than the optimum range (20~30 kg^-1). Available silicate (Av.SiO₂) ranged from 169 to 229 mg kg^-1, which was close to the minimum content (≥157 mg kg^-1) for rice paddy field. Available phosphate (Av.P₂O₅) content (24~39 mg kg^-1) was lower than the optimum range (80~120 mg kg^-1) for rice paddy field. CONCLUSION: For efficient agricultural use of reclaimed lands under government management, our results suggest that the application of organic matter and supplying deficient nutrients as well as desalinization is required.

• Journal of Soil and Groundwater Environment
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• v.22 no.1
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• pp.49-58
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• 2017

Biotic ligand model (BLM) and species sensitivity distribution (SSD) were used to determine the site-specific Cu threshold concentration (5% hazardous concentration; HC5) in soil pore water. Model parameters for Cu-BLM were collected for six plants, one collembola, and two earthworms from published literatures. Half maximal effective concentration ($EC_{50}\{Cu^{2+}\}$), expressed as $Cu^{2+}$ activity, was calculated based on activities of major cations and the collected Cu-BLM parameters. The $EC_{50}\{Cu^{2+}\}$ varied from 2 nM to $251{\mu}M$ according to the variation in environmental factors of soil pore water (pH, major cation/anion concentrations) and the type of species. Hazardous activity for 5% (HA5) and HC5 calculated from SSD varied from 0.076 to $0.4{\mu}g/L$ and 0.4 to $83.4{\mu}g/L$, respectively. HA5 and HC5 significantly decreased with the increase in pH in the region with pH less than 7 due to the decrease in competition with $H^+$ and $Cu^{2+}$. In the region with pH more than 7, HC5 increased with the increase in pH due to the formation of complexes of Cu with inorganic ligands. In the presence of dissolved organic carbon (DOC), Cu and DOC form a complex, which decreases $Cu^{2+}$ activity in soil pore water, resulting in up to 292-fold increase in HC5 from 0.48 to $140{\mu}g/L$.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.3
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• pp.213-236
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• 2001

The ionic composition of soil solution is related to a nutrient uptake by plant. Many models for estimating ionic composition of solution have been developed, and most of them have been used for calculating a content of mineral and ionic species in a geochemical point of view. An approximation model considering both cation and anion in soil solution was developed. Variables such as pH, Eh, EC, cations(K, Ca, Mg. Na, Fe, Mn, Al, $NH_4{^+}$), anions(Si, S, P, CY, $NO_3{^-}$, $HCO_3{^-}$ and chemical equilibria of ionic species in soil solution were input into Excel sheet. The activities of soluble ion, ionpairs and complexes of input element were estimated by Newton-Raphson method using conditional equilibrium constant calculated by Davies equation and special models. Equilibrium contents of insoluble minerals and complexes were also calculated.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.29-37
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• 2011

The experiment was carried out to find the effects of transplanting time and vinyl-film mulching treatment on the growth of artemisia by randomized block design with three replications. The experiment site ($100{\times}130$ m) was temporally established in the south-eastern part of Saemangeum reclaimed tidal land (near Gwanghwal myun, Gimjae-gun, Jellabukdo). Artemisia plants had been partly suffered from salt injury, because soil salinities in some area during growing period had been measured higher than 10 dS $m^{-1}$. Growth of plant height and survival ratio of transplanted plants had been significantly correlated with soil salinity and then the regression equations between plant height (y) and soil EC (x) and between survival ratio (y) and soil EC (x) were expressed as y=-16.59ln(x)+43.852 and $y=0.6453x^2-17.566x+103.99$, respectively. It was concluded that early transplanting and vinyl mulching was more beneficial for biomass production of artemisia, because biomass was 6.41 times more in the early transplanting than in the late transplanting, and 2.63 times more in the vinyl-film mulching than in the no mulching treatment.

• Korean Journal of Medicinal Crop Science
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• v.25 no.1
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• pp.1-9
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• 2017

Background: Some plants have harmful effects on fungi and bacteria as well as other plants. Incorporating such plant into soil as green manure is effective in reducing population densities of soil pathogens. Methods and Results: Twenty-three species of green manure crops were cultivated after the harvest of 6-year-old ginseng and then incorporated into the soil at the flowering stage. The following year, the root rot ratio of 2-year-old ginseng and soil chemical properties were investigated. In the absence of green manure addition, the $NO_3$ content, electric conductivity (EC), and K content decreased by 95%, 79% and 65%, respectively. In the presence of green manure addition, $P_2O_5$ and $NO_3$ contents reduced by 41% and 25%, respectively. The "survived root ratio" of 2-year-old ginseng significantly increased by 56.2%, 47.5%, and 47.3%, in the Sorghum sudanense, Ricinus communis and Helianthus tuberosus treatment, respectively. In addition, there was a significant increase in the "survived root ratio" in the Secale cereale, Chrysanthemum morifolium, Atractylodes macrocephala, and Smallanthus sonchifolius treatments. The "survived root ratio" of ginseng showed a significant positive correlation with the soil pH and a negative correlation with the $NO_3$ contents, and EC. Conclusions: Cultivation of plant form the Chrysanthemum family as green manure, using mainly the rhizomes was effective for the control of root rot disease of ginseng.

• Journal of Soil and Groundwater Environment
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• v.12 no.6
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• pp.46-52
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• 2007

A toxicity method using bioluminescence producing bacteria, Escherichia coli DH5 RB1436, was developed and applied on solid environmental samples. In the assay, 1 g soil sample was mixed with 4 ml RB1436 strain. Sets amended with p-buffer were employed for control in soil test, showing approximately 108% of sets amended with combusted soils. Measurable differences were observed between relatively more polluted groups (HP) and less polluted groups (LP) of soil samples, showing average toxicity 43 and 26%, respectively, in direct soil toxicity test. $EC_{50}$'s for all soil groups appeared in the range of $1.8{\sim}4.6\;g$, but those of sediments from dam reservoir and refuses were below 0.22 g. This developed bioassay should prove useful as a screening test for toxicity in various types of environmental solid samples.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.6
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• pp.19-29
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• 2014

The objectives of this study were to monitor and analyse water quality and soil property in paddy fields where untreated wastewater is irrigated. Three paddy fields where streamflow mixed with untreated wastewater has been irrigated (untreated wastewater district, UWD) were selected for monitoring, and five paddy fields in Yongin area (Yongin district, YID) where water from Idong agricultural reservoir (well-managed) has been irrigated were selected for comparative evaluation. Electronic conductivity (EC), suspended solids (SS), total nitrogen (T-N), total phosphorous (T-P), $NO_3-N$, $Ca^{2+}$, $Mg^{2+}$, $Na^+$, total coliform (TC), fecal coliform (FC), and E. coli of the irrigation water in the UWD were significantly higher than those in the YID. Relatively high concentrations of EC, T-N, T-P, TC, FC, E. coli, copper (Cu), lead (Pb), zinc (Zn), and aluminium (Al) were shown in the irrigation water of the UWD especially during May to June. In general, the paddy soil in the UWD contained more Pb, Zn, and Cu than in the YID although the soil heavy metal contents in the UWD still meet the Korean soil contamination warning standards. No temporal trends in the heavy metal concentrations were found in paddy soils of the UWD. This study showed that the use of untreated wastewater to paddy fields has the possibility of negative impacts on water quality and soil, although long-term monitoring is needed to fully evaluate its effects.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.103-103
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• 2020