• Journal of Korea Soil Environment Society
• /
• v.4 no.1
• /
• pp.75-83
• /
• 1999

The purpose of this study is to investigate the chemical characteristics of the leachate for the open(illegal) dumping waste. In this study, the open dumping waste were mixed with 0, 5, 10, 15% of bentonite in each Iysimeter as a rate of weight. The simulation was evaluated by CODcr, ${NO_3}^-$, ${SO_4}^{2-}$, $Cl^-$ and heavy metals in leachate. As a result, the mixed waste with bentonite in all Iysimeters showed the reduction of CODcr and heavy metals were hardly detected. The removal rate of ${NO_3}^-$, ${SO_4}^{2-}$, $Cl^-$ was increased with the mixing rate of bentonite.

• Journal of Korea Water Resources Association
• /
• v.40 no.1 s.174
• /
• pp.73-88
• /
• 2007

The goal of this research is to develop and apply the generalized regression neural networks model(GRNNM) embedding genetic algorithm(GA) for the estimation and calculation of the pan evaporation(PE), which is missed or ungaged and of the alfalfa reference evapotranspiration ($ET_r$), which is not measured in South Korea. Since the observed data of the alfalfa 37. using Iysimeter have not been measured for a long time in South Korea, the Penman-Monteith(PM) method is used to estimate the observed alfalfa $ET_r$. In this research, we develop the COMBINE-GRNNM-GA(Type-1) model for the calculation of the optimal PE and the alfalfa $ET_r$. The suggested COMBINE-GRNNM-GA(Type-1) model is evaluated through training, testing, and reproduction processes. The COMBINE-GRNNM-GA(Type-1) model can evaluate the suggested climatic variables and also construct the reliable data for the PE and the alfalfa $ET_r$. We think that the constructive data could be used as the reference data for irrigation and drainage networks system in South Korea.

• Korean Journal of Soil Science and Fertilizer
• /
• v.38 no.3
• /
• pp.127-133
• /
• 2005

The measurement technique using laser distometer to estimate soil erosion on sloped upland was assessed for its possibility for application. This technique was practiced in lysimeter installed in Chuncheon and Pyeongchang in 2001. The lysimeter installed at Chuncheon has 12% slope, 10 m slope length, 2 m width, and soil texture was sandy loam, while the lysimeter installed at Pyeongchang showed 23% slope, 15 m slope length, 5 m width, and sandy loam soil. Change of surface soil height was monitored using laser distance meter before and after rainy season on same spots. The Investigated periods in Chuncheon and Pyeongchang were from 22 June to 22 September and from July to October, respectively. Precipitation in Chuncheon and Pyeongchang in this period was 892.2 and 931.9 mm, respectively. Rainfall over 60% of annual precipitation was concentrated on July and August in Chuncheon and September and October in Pyeongchang, respectively. By monitoring the change of surface soil height using laser distance meter before and after rainy season, eroded soil surface in up-down fallow field in Chuncheon was 0.874 cm, while eroded soil surface in slant furrow field in Pyeongchang was 1.127 cm, which correspond to 79.5 and $98.0MT\;ha^{-1}$. Soil erosion increased as furrow length increased. Amounts of estimated soil loss using laser distance meter was 0.98-1.18 times higher compared to the estimated values through Iysimeter experiment, which implies possibility for application to monitor soil loss particularly in up-down and slant furrowed field. However, in the lysimeter with contoured tillage, amount of estimated soil loss using laser distance meter was approximately a half compared to that from lysimeter experiment, which implies inadequacy of distance meter application in contour- tillage field. The great soil loss difference between distance meter and lysimeter might be caused by disruption of some of the contoured furrows in lysimeter. The measurement technique using distometer in this study could be useful to estimate soil loss especially in up-down and slant-tillage fields.

• Applied Biological Chemistry
• /
• v.44 no.2
• /
• pp.97-102
• /
• 2001

Cheju island depends on a hydrogeologically vulnerable aquifer system as its principle source of drinking water. Most of golf courses are located in the area which is important for the ground water recharge, and pesticides are applied to golf courses often at relatively high rates. Therefore, turf pesticides in golf course should be applied without adversely impacting ground water. In this experiment, downward movement of pesticides was monitored in model greens of golf course, where different adsorbents were layered in 3-cm thickness at 35-cm depth, and effect of the adsorption layer on the leaching loss of pesticides was investigated. Major leachings were observed in the periods of heavy rain and very limited leaching was observed under artificial irrigation. Fenitrothion and triadimefon, which have relatively short persistence and high adsorption coefficient, were found in the leachate in low concentrations only at the first rainfall event, around 20 days after the pesticide application. However, diniconazole, which has a relatively long half-life (97 days), was detected in the leachate during the whole period of experiment and concentration was much higher than those of the other pesticides. Maximum leachate concentrations were 1.9, 10.3, and 84.5 ${\mu}l^{-1}$ for fenitrothion, triadimefon, and diniconazole, respectively. Therefore, in golf course green which allows rapid water percolation and has extremely low adsorption capacity, persistence in soil could be more important factor in determination of leaching potential of pesticides. Total quantity of pesticides leached from the model green was <0.2% for fenitrothion and triadimefon and 1.8% for diniconazole. Adsorption layers significantly reduced pesticide leaching, and active carbon and Orpar were more effective than zeolite. In the model green having adsorption layer of active carbon or Orpar, leaching loss of pesticides was reduced below 0.01% of the initial application.