Pil-Joo Kim

Dynamics of Heavy Metals in Soil Amended with Oyster Shell Meal

A large amount of oyster-shell waste has been illegally disposed at oyster farm sites along the southern coast of Korea, which already created serious environmental problems. Therefore, the study was undertaken to increase the consumption of oyster shell meal as a soil amendment. The effects of oyster shell meal on dynamics of heavy metals and uptake of heavy metals by spring Chinese cabbage were evaluated in silt loam soil (in Gyeongsang National University, Jinju, Gyeongnam-do, Korea), where 0, 4, 8, 12 and 16 Mg oyster-shell meal fertilizer were added. Lime treatment (2 Mg ) was selected as a control. In the results of this study, cabbage yields were increased by increasing levels of oyster-shell meal fertilizer. With increasing levels of oyster-shell meal fertilizer, total heavy metals concentrations were not significant among treatments. However, 0.1N HCl extractable heavy metals concentration was significantly reduced due to increasing of soil pH. A lot of portion (ca. ) heavy metals fraction of all fractions was residual phase in soil after harvesting. The contents of Cu, Mo, Zn in cabbage were slightly increased by increasing levels of oyster shell meal fertilizer. However, there were no toxic symptoms of heavy metals during cultivation. Conclusively, it was estimated that oyster shell fertilizer could be a good amendment to increase productivity of crop and reduce uptake of heavy metals by crop and mobility of heavy metals in soil.

Effects of Water Management Methods on CH₄ and N₂O Emission From Rice Paddy Field

The effects of water-saving irrigation on the emissions of greenhouse gases and the prokaryotic communities in rice paddy soils were investigated through a field experiment. In the Water-Saving (WS) irrigation, the water layer was kept at 2~3 cm while it was kept at 6 cm in the Continuousiy Flooding (CF) irrigation. A plot was treated with Intermittently Drainage (ID) that is drained as fine cracks on the floor were seen after transplanting. GHGs emission amounts from WS plots were reduced by 78.1% compared to that from CF plot and by 70.7% compared to that from ID plot, meaning that WS could help contribute to mitigation of the greenhouse gas accumulation in the atmosphere.

Effect of Organic Residue Incorporation on Salt Activity in Greenhouse Soil

In Korea, salt stress is one of the major problems limiting crop production and eco-environmental quality in greenhouse soil. The objective of this study was to evaluate the effectiveness of organic residues (Chinese milk vetch, maize stalk, rice straw, and rye straw) for reducing salt activity in greenhouse soil. Organic residues was incorporated with salt-accumulated soil (EC, 3.0 dS ) at the rate of 5% (wt ) and the changes of electrical conductivity (EC) was determined weekly for 8 weeks under incubation condition at . The EC, microbial biomass carbon (MBC), and water soluble ions in soil was strongly affected by C/N ratio of organic residues. After 8 weeks incubation, the concentration of water soluble , and was significantly decreased in organic residues having high C/N ratio (maize stalk, rice straw, and rye straw) incorporated soil compared to organic residues having lower C/N ratio (Chinese milk vetch) incorporated soil. The EC value in Chinese milk vetch incorporated soil was higher than control treatment. In contrast, maize stalk, rice straw, and rye straw amended soil was highly decreased the EC value compared to control and Chinese milk vetch applied soil after 4 weeks incubation. Our results indicated that incorporation of organic residues having high C/N ratio (>30) could reduce salt activity resulting from reducing concentration of water soluble ions.

Effect of Irrigation Water Salinization on Salt Accumulation of Plastic Film House Soil around Sumjin River Estuary

The causes of salt accumulation in soils of plastic film houses nearby Sumjin river estuary in Mokdo-ri(), Hadong, Gyeongnam, Korea were investigated in 2006. With chemical properties soils and water analyzed and fertilization status monitored, the study showed that mean salt concentration of soil was much higher at EC than the Korean average (EC ) in 2000s for plastic film houses soil with exchangeable Na and water-soluble Cl , and then might result to salt damage in sensitive crop plants. Salt concentration of ground water used as main irrigation water source contained very high EC with corresponding value of . Particularly, increase of EC value was directly proportional with the increased pumping of ground water used as a water-covering system in order to protect the temperature inside plastic film houses from the early winter season. High Na and Cl portion of ions in water might had contributed to the specific ion damage in the crops. Secondly, heavy inputs of chemicals and composts significantly increased the accumulated salts in soil. Conclusively, salt accumulation might had been accelerated by use of salted-groundwater irrigation and heavy fertilization rate. To minimize this problem, ensuring good quality of irrigation water is essential as well as reducing fertilization level.

Effect of Gypsum Application on Reducing Methane (CH 4 ) Emission in a Reclaimed Coastal Paddy Soil

BACKGROUND: Gypsum() is known as an ideal amendment to improve soil quality of the reclaimed coastal land. Since gypsum has very high concentration of electron acceptor like , its application might be effective on reducing emission during rice cultivation, but its effect has not been studied well. METHODS AND RESULTS: The effect of gypsum on emission and rice growth characteristics was studied by pot test, which was packed by reclaimed paddy soils collected from Galsa, Hadong, Gyeongnam province. Chemical-grade gypsum was applied in two soils having EC 2.25 and 9.48 dS/m at rates of 0, 0.5, 1.0 and 2.0%(wt/wt). emission was characterized a week interval by closed chamber method during rice cultivation. emission rate was significantly decreased with increasing salt accumulation and gypsum application levels. With increasing gypsum application, dissolved concentration in the leachate water was significantly increased, which might have suppressed production in soil. Total flux was dramatically decreased with increasing gypsum application. In contrast, rice yield was increased with increasing gypsum application and then achieved maximum productivity at 1.0% gypsum application in two soils. CONCLUSION(s): Gypsum is a very good soil amendment to suppress emission in reclaimed coastal paddy soils, and improve rice productivity and soil properties. The optimum application level of gypsum is assumed at ca. 1% to improve soil productivity with reducing effectively emission during rice cultivation.

Determining Effect of Oyster Shell on Cadmium Extractability and Mechanism of Immobilization in Arable Soil

Abstract BACKGROUND: Oyster shell(OS) is alkaline with pH 9.8, porous, and has high concentration of CaCO 3 . It could be used as an alternative of lime fertilizer to immobilize cadmium(Cd) in heavy metal contaminated arable soil. Therefore, this study has been conducted to compare effects of calcium(Ca) materials [OS and Ca(OH) 2 ] on Cd extractability in contaminated soil and determined mechanisms of Cd immobilization with OS.METHODS AND RESULTS: Both Ca materials were added at the rates of 0, 0.1, 0.2, 0.4, and 0.8% (wt Ca wt-1) in Cd contaminated soil and the mixtures were incubated at 25℃ for 4 weeks. Both Ca materials increased pH and negative charge of soil with increasing Ca addition and decreased 1N NH 4 OAc extractable Cd concentration. 0.1 N HCl extractable Cd concentration markedly decreased with addition of OS. 1 N NH 4 OAc extractable Cd concentration was related with pH and net negative charge of soil, but not with 0.1 N HCl extractable Cd concentration. We assumed that Cd immobilization with Ca(OH)

Effect of Phosphate Fertilizer and Manure in Reducing Cadmium Phytoavailability in Radish-grown Soil

ACKGROUND: Cadmium (Cd) has long been recognized as one of most toxic elements. Application of organic amendments and phosphate fertilizers can decrease the bioavailability of heavy metals in contaminated soil. METHODS AND RESULTS: This study was conducted to evaluate effect of combined application of phosphate fertilizer and manure in reducing cadmium phytoavailability in heavy metal contaminated soil. Phosphate fertilizers [Fused and super phosphate (FSP) and (DPP)] and manure (M) were applied as single application (FSP, DPP, and M) to combined application (FSP+M and DPP+M) before radish seeding. decreased extractable Cd and plant Cd concentration, mainly due to increases in soil pH and negative charge. However, FSP increased extractable Cd and plant Cd concentration. Manure significantly increased soil pH and negative charge. Combined application of phosphate fertilizer and manure were much more effective in reducing Cd phytoavailability than a simple application of each component. Calculated solubility diagram indicated that Cd concentrations in the solution of soils amended with phosphate fertilizers and manure were undersaturated with respect to all potential Cd minerals [, , , and ]. Plant Cd concentration and extractable Cd were negatively related to soil pH and negative charge. CONCLUSION: Alleviation of Cd phytoavailability with phosphate fertilizer and manure can be attributed primarily to Cd immobilization due to the increase in soil pH and negative charge rather than Cd and phosphate precipitation. Therefore, combined application of alkaline phosphate materials and manure is effective for reducing Cd phytoavailability.

Evaluation of Fertilization Effect of Slow-Release Complex Fertilizer on Pepper Cultivation

Slow-release fertilizers (SRF) have been used to reduce nutrient loss through increasing fertilizer efficiency and to save labor. Several SRFs were developed for rice plant in Korea, but there is few for horticultural crop plants. Two slow-release complex fertilizers, 100T and 150T, which made for controlling nitrogen release time up to 100 and 150 days, respectively, were selected for the incubation test cto evaluate nitrogen (N) release rate in soil. The N of urea selected as the control was completely released within a week after application. Sixty three and 53% of total N were released from 110T and 150T of slow release fertilizers within 8th weeks after application, respectively. For pepper cultivation CF110 and CF150, new slow-release complex fertilizer, were made of mixing 40% of conventional fertilizer and 60% of 110T and 150T, respectively, based on the amount of recommended fertilizer for pepper cultivation , and were totally applied before pepper transplanting in the field as the basal fertilizer. Inorganic N concentration in soil was higher in the CF110 treatment than in the control (NPK) at all period of pepper cultivation. In the CF150 treatment concentration of inorganic N in soil was low compared to control up to 8th weeks after transplanting. However, there was no difference in plant height and nutrient content of pepper leave between CF110 treatment and the control. In comparison, plant height was significantly lower in CF150 than the control and CF110 treatments. Around 4% of fresh pepper yield was increased in CF110 compared to the control, but it was decreased to about 2% by CF150 treatment. Conclusively, CF110 form could be recommended as a slow release fertilizer for pepper cultivation.

Determination of Cadmium and Zinc Contamination Source in Arable Soil in the Vicinity of a Zinc Smelting Factory

Agricultural area in the vicinity of the smelting factory in Kyeongbuk province, the third △△ largest zinc smelting factory in the world, was contaminated by high concentration of heavy metals. However, the heavy metals source was not yet directly traced and thus, resulted to a conflict between the factory and residents within its vicinity. In order to determine the level of heavy metal contamination in the arable lands located at the north eastern part of the factory, soils were sampled systematically. To find out the major reason for the occurrence of this problem, waters and aerosols were sampled with constant intervals to the upward and downward direction from the factory and were analyzed to find out the heavy metal concent- rations. Cadmium (Cd) and zinc (Zn) of the heavy metals were highly accumulated more than the Korean warning criteria (Cd 1.5, Zn 300 mg kg -1 ) with mean values 1.7 and 407 mg kg -1 , respectively, at the surface soils (0-20 cm), and heavy metal concentration significantly decreased with increasing soil depth. In addition, the concentration of both metals slightly decreased with increasing distance from the factory to the surface soils. Cadmium and Zn were detected in the upward stream water with low concentration and concentrations increased significantly in the downstream after passing across the factory. Aerosol samples also showed traces of Cd and Zn which could be attributed to the contamination of the water system and the surface soils. Conclusively, Cd and Zn emitted from the smelting factory moved with the aerosol in the atmosphere △△ and thus, contaminated the agricultural areas and the water system within its vicinity.

Evaluation of Bioavailability of Phosphorus Accumulated in Arable Soils

Abstract BACKGROUND: Soil utilization pattern can be the main factor affecting soil physico-chemical properties, especially in soil phosphorus (P). Understanding the distribution and bioavailability of P is important for developing management to minimize P release from arable soils to environment. This study was conducted to evaluate the potential bioavailability of soil organic P by using phosphatase hydrolysis method. METHODS AND RESULTS : Twenty-four soils from onion-rice double cropping and 30 soils from plastic film house were selected from Changyeong and Daegok in Gyeongnam province, respectively. The P accumulation pattern (total P, inorganic P, organic P, residual P) and water soluble P were characterized. Commercial phosphatase enzymes were used to classify water-extractable molybdate unreactive P from arable soils into compounds that could be hydrolysed by (i) alkaline phosphomonoesterase (comprising labile orthophosphate monoesters), (ii) a combination of alkaline phosphomonoesterase and phosphodiesterase (comprising labile orthophosphate monoesters and diesters), and (ⅲ) phytase (including inositol hexakisphosphate). Available P was highly accumulated with 616 and 1,208 mg/kg in double cropping system and plastic film house, respectively. Dissolved reactive P (DRP) and dissolved unreactive P (DUP) had similar trends with available P, showing 24 and 109 mg/kg in double cropping and 37 and 159 mg/kg in plastic film house, respectively, indicating that important role of dissolved organic P in the environments had been underestimated. From the result of phosphatase hydrolysis, about 39% and 66% of DUP was evaluated as bioavailable in double cropping and plastic film house, respectively. CONCLUSION(S) : Orthophosphate monoester and orthophosphate diester accounted for high portion of dissolved organic P in arable soils, indicating that these organic P forms give important impacts on bioavailability of P released from P accumulated soils. Key Words: Bioavailability, Phosphatase hydrolysis, Soil phosphorusResearch Article Open Access