• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.362-367
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• 1998

To investigate the effects of simulated acid rain(SAR) on the downward movement of mineral nutrients, SARs of different pH were applied to the soil. SAR of pH 2.0 decreased the soil pH greatly, while SAR of pH 4.0 and 6.0 did not change the soil pH to compare to that of SAR of pH 2.0. Decrease in soil pH was in the order of sandy loam > loam > clay loam. The amoumt of leached exchangeable and soluble bases from the soil due to the penetration of SAR was in the order of Ca >Mg > K. After application of 1200mm SAR of pH 2.0 in to the soil downward mean movements of the exchangeable and soluble bases was in the order of Mg > Ca > K in sandy loam and loam soil and Ca > Mg > K in clay loam soil. Downward movements of the those bases under pH 4.0 into the soil was in the order of Mg > K > Ca in sandy loam and clay loam, and K > Mg > Ca in loam soil. Available phosphorus moved slightly downward with increasing acidity of the SAR.

• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.143-147
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• 2006

This study was carried to investigate the effect of soil texture on the growth and the contents of quercetin-glycoside and lignans, and to improve the qualities of Saururus chinensis Baill. Soil texture resulted no significant effects on the number of nodes, the number of leaves, the number of branches and dry matter ratio. However, the shoot dry weight was higher in sandy loam, loam, silt loam and sand soil in that order. Although the weight of rhizomes of below 5 mm in diameter was not significantly different among soil textures, the weight of rhizomes between 5.1 and 10.9 mm and the weight of rhizomes of above 11 mm in diameter ranged $437{\sim}465\;g$ and was larger in clay loam than in other soil textures. No significance difference was showed in rhizome dry ratio ranging from 19.1 to 20.8%. The amount of quercetin-glycoside in leaves was higher in loam and sandy loam and ranged from 219.3 to 222.4 mg/100 g of quercetin-glycoside quercitrin, rutin, isoquercitrin and hyperin were higher in that order. On the other hand, quercetin-glycoside contents in stem were 14.8 mg/100 g and 12.4 mg/100 g in sandy and sandy loam, respectively, and were higher than in other soil textures of quercetin-glycoside constituents, the content of rutin was the highest. The content of lignans was increased in clay loam, loam, sandy loam, and sandy in that order of lignans, the manassatin B was the highest.

• Magazine of the Korean Society of Agricultural Engineers
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• v.27 no.1
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• pp.37-45
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• 1985

To define the amount of consumptive use of upland crops, the moisture consumption characters were investigated with different soil moisture content by soil properties(loam, sandy loam, sand) at the experimental farm of Kon-Kuk University from April 20 to July 20 1984. The results obtained are summarized as follows; 1. Total moisture consumption under bare soil condition had an order of loam> sandy loam> sand and showed an order of pF 1.5> pF2. 1> pF 2.7 by re-irrigation point and the average during the experimental period (92days) was 435. 9mm and the daily average moisture consumption was 4. 7mm. 2. The moisture consumption characters of bare soil plot obtained showed that the amount of irrigation water per one time and the days of intermission increased and, on the contrary, the times of irrigation and the total amount of irrigation water decreased by the increment of re-irrigation point in the same soil 3. Total moisture consumption of spring cabbage under open cultivation showed 528.6 rim in maximum and had an order of loam> sandy loam> sand. In the aspect of rc-irrigation point, it had an order of pFl. 5> pF 2.1> pF 2.7. In case the planning basic year was taken into account, the amount of irrigation water needed for open cultivation was 456. 3 mm and its average daily moisture consumption was 6. 2mm. 4. Total moisture consumption of summer cucumber under open cultivation showed 635. 8mm in maximum and had an order of loam> sandy loam> sand. In the aspect of re-irrigation point, it had an order of pF 1.5> pF2. 1> pF2. 7 In case the planning basic year was taken into consideration, the amount of irrigation water was 516. 9mm and its aversge daily moisture consumption was 6. 5mm. 5. The result of cabbage cultivation showed its maximum yield in loam soil when the pF values were maintained from 1,5 to 2.1 and then the evapotranspiration ratio was 1, 76 and also when the amount of irrigation water were similar, it showed effective to reduce the days of intermtission. 6. The result of cucumber cultivation showed its maximum yield in sandy loam soil when the pF value maintained from 1.5 to 1.7 and when the irrigation point maintained at pF 2,7 in sandy soil, its yield was severely decreased.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.220-225
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• 1994

This study was conducted to investigate the influence of treatment of fly ash on heavy metal contents in the grain. Rice was cultivated on the two types of paddy field, clay loam and sandy loam soil, with 0, 4, 8, 12t/10a of anthracite fly ash and bituminous coal fly ash, respectively. And soybean was cultivated on the same types of upland field with those of 0, 3, 6, 9t/10a, respectively. Also. rice and soybean were cultivated the same types of paddy and upland field with those ashes of 0, 12ton/10a and 0, 9ton/10a, yearly for three years. At the harvest time, the heavy metal contents in rice and soybean were Investigated. The results were summarized as follows : 1. Amount of application. 1) The contents of Cd in brown rice increased in the clay loam soil. Cr and Ni increased sandy loam soil with the application of anthracite fly ash. 2) The contents of Zn in rice increased in the sandy loam soil with the application of bituminous coal fly ash. 3) The contents of Cu in soybean increased with the application of anthracite and bituminous coal fly ash, but Zn, Pb, Cr and Ni increased only with the bituminous. 2. Successive application. 1) The contents of Cd in brown rice increased in the clay and sandy loam soil, however Cu, Zn, Ni, Cr and Fe increased only in sandy loam soil with the anthracite fly ash. 2) The contents of Cr in soybean were increased in the clay and sandy loam soil, but Cu, Fe increased only sandy loam soil with anthracite fly ash. 3) The contents of Cd, Zn, and Cr in brown rice increased in the clay and sandy loam soil, but those of Cu, Mn increased only in the sandy loam soil with application of bituminous. 4) The contents of Cd, Pb, and Cr in soybean increased in the sandy loam soil with the application of bituminous coal fly ash.

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

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.1
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• pp.149-158
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• 2007

To investigate the characteristics of the nitrogen mineralization of oil cakes according to changes in temperature(10, 20, $30^{\circ}C$) moisture(40, 50, 60, 70% of field capacity in loam and 50, 60, 70, 80% of field capacity in sandy loam), mineral nitrogen was measured in soil after incubation for 30 days. In addition, the mineralization in sandy loam and loam which had different soil texture were compared. According to incubating the castor seed, soybean, and rice bran cakes with soil, the higher the temperature and moisture content were, the higher the content of mineral nitrogen was observed. The content of mineral nitrogen was higher in sandy loam than loam. The content of mineral nitrogen was decreased with soil depth increasing and was also higher in sandy loam than loam.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.2
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• pp.131-135
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• 2007

This study was performed as an effort to reduce soil loss by investigating the phase of water flow according to soil texture and rainfall pattern and by determining the canopy cover subfactor in the RUSLE (revised universal soil loss equation). Red pepper was planted at the 15% sloped lysimeter of $2m{\times}5m{\times}0.5m$ ($width{\times}length{\times}depth$) with three different textured soils (loam, clay loam and sandy loam) and the relationship between amount and intensity of rainfall; soil loss and the amount of runoff; and amount of rainfall and runoff at different soil texture were measured at the experiment station of the National Institute of Agricultural Science and Technology (NIAST) during May to October of 2005. The amount of runoff increased with increasing amount of rainfall, showing difference in the relative increase rate of runoff at different soil texture. The increase rate of runoff with unit increase of rainfall for the lysimeter with red pepper was 0.44, 0.41 and 0.13 for loam, clayey loam and sandy loam, respectively. The minimum amount of rainfall for runoff was 23.53 mm for sandy loam, 10.35 mm for loam and 5.46 mm for clayey loam, respectively. The canopy cover subfactors of red pepper were 0.425, 0.459, and 0.478 for sandy loam, loam and clayey loam, respectively.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.375-383
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• 2020

BACKGROUND: Bisphenol A (BPA) is a chemical widely used in polycarbonate plastics, epoxy resins. BPA is an endocrine disruptor. Residue of BPA in agricultural environments is a major concern. The objective of this study was to understand the characteristics of the uptake and distribution of BPA and its metabolites introduced into the agricultural environment to crops, and to use it as basic data for further research on reduction of BPA in agricultural products. METHODS AND RESULTS: This study established the analysis method of BPA and its metabolites in soil and crops, and estimated the intake of BPA and its metabolites from lettuce (Lactuca sativa) grown in sandy loam and loam soil, which are representative soils in Korea. The two major metabolites of BPA were 4-hydroxyacetophenone (4-HAP) and 4-hydroxybenzoic acid (4-HBA). BPA, 4-HAP and 4-HBA have been analyzed by using liquid chromatography tandem mass spectrometry (LC-MS/MS). These substances were detected in sandy loam and loam soil, indicating that certain portions of BPA were converted to 4-HAP and 4-HBA in the soil; however, it was observed that only 4-HBA migrated to lettuce through the roots into crops. CONCLUSION: The uptake residues showed the BPA and 4-HAP were not detected in lettuces grown on sandy loam (SL) and loam (L) soil treatments that were applied with of 10 ng/g, 50 ng/kg and 500 ng/g of BPA. However, the 4-HBA was detected at the level of 7 ng/g and 11 ng/g in the lettuce grown in sandy loam and loam soil that were treated with the 500 ng/g of BPA, respectively, while the 8 ng/g of 4-HBA was measured in the lettuce cultivated in the loam that was treated with 100 ng/g of BPA. This result presents that the BPA persisting in the soil of the pot was absorbed through the lettuce roots and then distributed in the lettuce leaves at the converted form of 4-HBA, what is the oxidative metabolite of BPA.

• Journal of Biosystems Engineering
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• v.33 no.1
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• pp.7-13
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• 2008

The tillage depth control system is one of the most salient control system of tractor implements. A contact-type height sensor was developed to measure ground clearance for the tillage depth control. The height sensor was fabricated in this study, and its efficacy in a tillage depth control system was evaluated. Experiments were conducted in order to determine both static and dynamic detection characteristics of the height sensor using soil bin system on the sampled soil (sandy loam, sand, clay loam). The results of the static detection characteristics showed that in the case, sandy loam soil despite and clay loam soil at a wet basis moisture content of 30%, large measurement errors were observed a due to penetration of a plastic puck into the sampled soil. The results of the dynamic detection characteristics showed that the height sensor detected the distance from the ground of sandy loam soil despite the uneven nature of the ground surface and the changes in traveling speed $1km/h{\sim}5km/h$ at a wet basis moisture content of 10%.

• Magazine of the Korean Society of Agricultural Engineers
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• v.27 no.1
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• pp.71-76
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• 1985

The objectives of this field experiment was to determine and recommend the water requirement for harrow considering the factors of soil class and soil moisture status. Experiment was conducted at the -paddy field of the Office of Rural Development in Chungnam Province. The results of experiment were summarized as follows: 1. Continuous drought day of 10-yr return period in transplanting season was about 25 days and the water content ratios at that point were approximately 20% in clayey-loam soil and 12% in sandy-loam soil irrelevantly to the soil-depth. 2. It was recommended that harrow-water requirement for standard design were approximately 9Omm in clayey-loam soil, 110mm in loamy soil and l3Omm in sandy-loam soil.