• Journal of Soil and Groundwater Environment
• /
• v.27 no.3
• /
• pp.1-10
• /
• 2022

Most wells developed in Jeju island before the enactment of the Groundwater Management Ordinance in 2002 are vulnerable to aquifer contamination due to inflow of upper groundwater having the high concentration of nitrate nitrogen, likely due to incomplete grouting in upper section of the wells. Although these wells require entire reinstallation, it is often necessary to rehabilitate the existing wells due to various constraints. Therefore, to identified the inflow section of contaminants, the thermal level sensor (TLS) technique was firstly applied for three wells, which enables to monitor temperature variations in every 50 cm depth. Then, the grouting material was injected to the upper section to prevent the inflow of upper contaminated groundwater into the entire aquifer. By applying TLS technique, it was found that the temperature deviations in the upper groundwater inflow section decreased sharply. Moreover, both the change in the concentration of nitrate nitrogen in the rainy/dry seasons and the average concentrations were found to decrease rapidly after grouting material injection. Consequently, the application of TLS proposed in the study turned out to be appropriate to prevent aquifer contamination.

• The Korean Journal of Ecology
• /
• v.19 no.5
• /
• pp.375-383
• /
• 1996

Effects of forest fire on soil nutrients in pine forests were studied in Dosong, Kangwon Province in Korea. Soil samples were collected from burned sites and unburned sites (control) at Kusungri, Sampori and Wunbongri. Soil pH in burned sites was higher than that in unburned sites. Soil organic matter did not differ significantly between the burned and unburned sites. Concentrations of available phosphorus in burned soils were about 3 times higher than those in unburned sites. Also, concentrations of ammonium nitrogen were markedly increased in burned sites contrary to those of nitrate nitrogen. Total nitrogen, however, showed no significant difference between the sites. Concentrations of cations, calcium and magnesium, in burned sites were also significantly increased. Thus, even though forest fire removed the aboveground biomass of pine forests, inorganic nutrients added from ash may play a great role for growth of sprouts and seedlings after forest fire.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.09a
• /
• pp.175-178
• /
• 2004

Little study has been published specifically addressing the dynamics of nitrate reducing bacteria (NBR) during the bioremediation of nitrate-contaminated aquifer. In our previous study we successfully quantified fumarate-enhanced microbial nitrate reduction rate in a nitrate-contaminated aquifer by using a series of single-well push-pull tests (PPTs). In this study we analyzed the suspended population during PPTs. To monitor changes in the microbial community, PCR amplification of 16S rDNA genes and denaturing gradient gel electrophoresis (DGGE) were used to study the dynamics of the bacterial community in detail. Before the stimulation of NBR, the dominant DGGE bands obtained by PCR were affiliated with V-Proteobacteria consisting of Acinetobacter spp. and Pseudomonas fluorescens. However, as NBR biostimulation proceeded, the dominant patterns of DGGE bands changed, and they were affiliated with Azoarcus denitrificans Td-3 and Flavobacterium xanthum. Azoarcus denitrificans Td-3 is known to completely reduce nitrate to nitrogen gas. The series of single-well push-pull tests in this study should prove useful for conducting rapid, low-cost feasibility assessments for in situ denitrification and provide important information about which microorganisms play a key role in bioremediation of a nitrate contaminated aquifer.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.513-518
• /
• 2000

It has been acknowledged that fertilizer, natural soil nitrogen and animal waste, municipal waste have different mass ratio of nitrogen which is presented as a symbol of $\delta^{15}$N. and that the values of $\delta^{15}$N for fertilizer and natural soil nitrogen and animal waste are placed less than +5$\textperthousand$ and higher than +10$\textperthousand$, respectively. thus, Nitrogen pollution sources and contribution can be interpreted in watershed through $\delta^{15}$N analysis and then, analysis is performed with Kjeldhl-Dumas method. In this study, The values of $\delta^{15}$N are between +1.46$\textperthousand$ and +8.97$\textperthousand$, and the nitrate concentration is placed less than 3.31mg/L and higher than 0.19mg/L, respectively. Thus, this watershed is noncontamination area at the present time. But as a result of $\delta^{15}$N, contribution of natural soil nitrogen be discovered in this watershed, presently.

• Korean Journal of Agricultural Science
• /
• v.49 no.2
• /
• pp.379-387
• /
• 2022

A large amount of the mineral nitrogen is necessary for crop growth. With the use of nitrogen fertilizers, agricultural yield has increased during the last few decades. However, at the same time, nitrate from the cultivated land can be a source of environmental pollution, especially in water systems. For nitrogen management, it is necessary to analyze the pattern of nitrogen movement in soil. In this study, nitrogen leaching in upland soils was evaluated using undisturbed lysimeters with different soil textures during sesame cultivation. The soil texture of the lysimeters was clay loam (Songjung series) and sandy loam (Sangju series) soils. Sesame was cultivated from May 25 to August 24 in 2020. The standard amount of NPK fertilizer (N-P₂O₅-K₂O = 2.9-3.1-3.2 kg·10 a^-1) was applied before sowing. The amount of nitrogen leaching was calculated by multiplying the nitrogen (NO₃-N + NH₄-N) concentration and the amount of water drained below 1.5 m soil depth. The water was drained through percolation into macropores in the clay loam lysimeter. In contrast, in the sandy loam lysimeter, water drained more slowly than in the clay loam lysimeter. There was a slight difference in the total amount of leachate during the cultivation period, but the amount of nitrogen leaching was high in sandy loam soil. During the sesame cultivation period, the amount of nitrogen leaching from clay soil was 5.64 kg·10 a^-1, and 10.70 kg·10 a^-1 for sandy soil. We found that there was a difference in leaching depending on the soil physical characteristics. Therefore, it is necessary to consider the characteristics of soil to evaluate the leaching of nitrogen.

• Korean Journal of Environmental Agriculture
• /
• v.41 no.3
• /
• pp.158-166
• /
• 2022

BACKGROUND: Kiwifruit is a fruit tree with relatively small cultivation area in Korea and researches on its soil and physiology are very limited compared to those on cultivar development. Therefore, there are limited information for farmers to cope with the reduction in productivity due to various physiological disorders and premature aging. This study was conducted to investigate the soil and leaf chemical properties, and fruit characteristics, which will be used as basic data for stable kiwifruit orchard soil management. METHODS AND RESULTS: The soil and leaf chemical properties, and fruit characteristics were investigated for two years in 16 kiwifruit orchards growing 'Hayward' (Actinidia deliciosa) in Jeollanam-do and Gyeongsangnam-do. Soil and leaf samples were collected in July and fruit quality was investigated by harvesting fruits about 170 days after full bloom. The average soil chemical properties of kiwi orchards were generally higher than the recommended level, except for pH, and especially, the exchangeable potassium reached about 300% of the recommended level. The proportions of orchards that exceeded the recommended level of soil chemical properties were 63, 31, 100, 69, 94, 88 and 69% for pH, EC, organic content, available phosphate, and exchangeable potassium, calcium and magnesium, respectively. Thirty-three percent of orchards had more than 100 mg/kg of nitrate nitrogen in soil. Available phosphate in soil showed a significantly positive correlation with leaf nitrogen, phosphoric acid and calcium content, but showed a significantly negative correlation with leaf potassium content. The magnesium content in the leaves was significantly correlated with soil pH. The highest fruit weight was observed in about 25 g/kg of leaf nitrogen content which could be attained when plants were grown on the soil containing about 100 mg/kg of nitrate nitrogen content. The average soluble solids content among 16 orchards was 9.58 °Brix at harvest and 13.9 °Brix after ripening, which increased about 45%, and the average fruit weight was about 110 g. CONCLUSION(S): For fruit quality, fruit soluble solids (sugar compounds) content was significantly correlated with leaf potassium content, fruit hardiness with leaf total nitrate, calcium and magnesium, and fruit titratable acidity with leaf magnesium; however, leaf calcium and magnesium negatively affect the soluble solids contents in fruits.

• The Korean Journal of Ecology
• /
• v.28 no.4
• /
• pp.189-192
• /
• 2005

We tested the field adaptation of Betula schmidtii on the abandoned coal-mine soil with sludge amendment methods for promoting physiological activity of B. schmidtii seedlings under several environmental stress. Sewage sludges were amended to coal-mine soil with B. schmidtii seedlings which grown in the mixture of artificial soil and composted sludge soil before transplanting (before-fertilized treatment, BF) and fertilized with composted sludge after transplanting (after-fertilized treatment, AF). The percent of establishment of seedlings for AF (80.7%) was lower than that for BF (92.7%). Nitrate reductase activity and photosynthetic pigment content were higher in AF than in BF, but malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were lower in AF than in BF These results represent that after-fertilized seedlings increase resistance against physiological stress at field condition using nitrogen source of composted sludge. On the contrary, before-fertilized seedlings were susceptible to environmental stress on abandoned coal-mine soil by exhausting of nitrogen source from composted sludge.

• Journal of Soil and Groundwater Environment
• /
• v.8 no.1
• /
• pp.57-67
• /
• 2003

Nitrate contamination by human activities is a serious problem to water-supply in agricultural area. Shallow groundwater is the main source of water-supply, but it is very sensitive to contamination. Study area for nitrate contamination is a region of Iljuk, Kyunggi where is an agricultural area having many livestock facilities in various scales. As a result, the points having availability of incoming of external contaminant are 77%, and the ones over the Drinking Water Limit (DWL) are 32～42%. For a nitrogen isotope analysis, all the points having availability of incoming of external contaminant have $\delta$$^{15}$ N-NO$_3$ values over 5$\textperthousand$, and the points of 59% are strongly affected by nitrogen originated from animal wastes. The major source of nitrate in this area is intensive livestock facilities. Even though a livestock facility had enclosed, it affects groundwater quality for a long time. The chemical property of contaminant source is various according to animal species in surface water, but not in groundwater since some solutes are removed by reactions during an inflow to subsurface.

• Journal of Plant Biology
• /
• v.6 no.3
• /
• pp.1-5
• /
• 1963

Determination of the chemical properties in some forest soils and the naked soil developed on granite in the mountains of the vicinity of Seoul, Korea are presented in this study. The soil under the broad leaved forests has a higher nutrient indicated by available nitrogen, nitrate nitrogen, and phosphorus contents, compared with that under the needle leved forests. On the contrary the content of organic matter and base exchange capacity in the needle forest soils is higher than in the broad leaved forest soils. The significant difference between two horizons of each soil appeared only to be in the content of the available phosphorus, and that of the needle and the broad leaved forest soils, and the naked soils was the nitrate nitrogen and organic matter content among the several chemical properties.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2001.10a
• /
• pp.479-483
• /
• 2001

This Study was carried out to know the soil properties and the quality of shallow groundwater in the plastic film house fields around mid-Korea. This study was conducted at 11 sites in Suweon, Pyungtaek, Yongin, and Chunchen on May, June, July and August in 1999. The the average concentration of nitrate-nitrogen was 19.1 mg/L, it reached almost to the limiting level, 20 mg/L. Moreover about 36.4% of survey sites exceeded limiting level to agricultural groundwater quality. And Sulfur concentrations also at some sites exceeded to agricultural groundwater quality limit level (50 mg/L), which could make damage to the crop. Nitrate-nitrogen, which is one of the most important factors in the groundwater quality, It has highly positive correlation with any other ion in groundwater. This result showed that groundwater quality management practices should be taken for the agricultural production as well as for environment at the plastic film house areas.