• Korean Journal of Soil Science and Fertilizer
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• v.22 no.2
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• pp.86-92
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• 1989

This experiment was conducted to find out the effect of soil improvement on the changes of soil physical properties and the silage yield of corn in the newly-reclaimed sloped land. Corn (Suweon 19) was cultivated under the six different treatments at Songjeong loam, 20 percent slope, during 1985 to 1987 and various soil physical properties and silage yield were investigated. Growing Degree Days of corn during the growing season were $820.6^{\circ}C$ in 1985, $810.2^{\circ}C$ in 1986, and $812.4^{\circ}C$ in 1987. The changes of soil bulk density were high variances by different treatments in 1st year, but sluggish in 2nd year. In 3rd year, the control plot was the highest, but the integrated improvement plot was the lowest than the other plots. Soil hardness was reduced in subsoiling and integrated improvement plot with deep plowing, and water stable aggregates and air permeability were higher in these plots. Moisture retention was no differences between treatments. Dry matter yield of corn was decreased in the 2nd year than the 1st year, but increased in the 3rd year. Increasing ratio of yield was in the order of integrated improvement > subsoiling > lime > phosphate > compost > control plot. Correlation among the dry matter yield and soil physical properties were significant at 1%, but moisture retention of soil was not significant at 5%.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.2
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• pp.105-110
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• 1994

Field experiment was carried out to obtain the basic information on the soil improvement with different improved methods on job's tears yield and soil properties in the newly-reclaimed land from 1985 to 1988. Job's tears yield, soil properties and annual changes of soil were investigated and analyzed. Soil bulk density and hardness of topsoil decreased from 1st year to 3rd year, but those increased in 4th year. Soil pH of topsoil had no differences in different soil depths and cultivated years. Average yield of job's tears in the integrated improvement plot was 2.16ton/ha. That was increased by 49% than the control plot. Crop yield was greatest in order of integrated improvement>subsoiling>phosphate>lime>compost>control plot. Correlation coefficients of job's tears yield with soil pH and organic matter content were higher significantly. Also those of subsoil were higher than topsoil. Ratios of annual changes of soil bulk density and hardness showed significant highly with job's tears yield. Also that soil pH was significant at 5 % level in the topsoil.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.189-194
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• 1994

This experiment was conducted to obtain basic information on the improved methods of soil physico-chemical properties and sweet potato yield cultivated on a newly-reclaimed land, a Songjeong loam soil. The crop was cultivated under the six different treatments for 4years since 1985 in the field conditions. Annual changes of soil properties and sweet potato yield were investigated and analyzed. Soil bulk density increased from the second year, and also soil hardness of topsoil increased, but that of subsoil had not tendency. Average yield of sweet potato for 4years in the integrated improvement plot was 32.68ton/ha, which is increased by 59% in comparison to that of the control plot. Crop yield was in order of integrated improvement>phosphate>subsoiling>lime>compost>control plots. The soil properties of the topsoil which showed high correlation coefficient to sweet potato yield were bulk density, hardness and cation exchange capacity(CEC), and those of the subsoil were bulk density, soil moisture and CEC. Ratios of changes of soil properties except organic matter content showed high significancy to sweet potato yield. Soil physico-chemical properties of the 4th year without soil conditioners application were worse than those of 3rd year.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.330-348
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• 2007

Soil problems and agricultural water management of the reclaimed land in Korea were reviewed through research results conducted in RDA and ADC. According to the Korean Soil Classification and Soil Survey(NIAST, 2002), the 5 soil orders with the 45 soil series were distributed on the fluvio-marine or marine deposit of the west and south coastal plains. Yeompo, Munpo, Hasa, Gwangwhal, and Poseung soil series were most commonly distributed soil on the fluvio-marine deposits, associated with tideland of the sea coast. Former 4 soils were Entisols, and the latest one was the Inceptisols. Buyong soil associated with Poseung series was an Alfisols. Extent of Myeongji soil, a Molisols, and Yongho soil, a Histosol, were minor. Salinity control and management problems were closely related with high water table and low percolation rate due to plow-pan layer developed during the leaching process in the silty textured soil. For evaluation of field salinity, use of an electromagnetic inductance, EM38, with GPS was helpful to understand salinity status and field variability. Deep plowing, subsoiling and drainage improvement by tile drainage might be effective in paddy with plow-pan. New technology such as variable rate fertilization might save fertilizers and thus reduce environmental impact of agriculture on water quality. Water quality of agricultural water resources in reclaimed land was less adequate than that of inland water resources. Proper crop management is necessary depended upon quality for crop growth as well as to match with water quality target.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.197-204
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• 1989

To evaluate the effect of soil improvement on the chemical properties and corn silage yield, this experiment was carried out in the newly-reclaimed sloped land. Corn (Suwon 19) was cultivated under the six different treatments including integrated improvement plot at Songjeong loam, 20 percent slope, from 1985 to 1987 and various soil chemical properties and silage yield were investigated. pH of topsoil was above 5.0 except for control and phosphate plot, but lime and integrated improvement plots were above 5.0 in subsoil. The contents of organic matter of topsoil were above 2.0% except control and subsoiling plot. Except control, the range of cation exchange capacity was 7.4-7.8 me/100g in topsoil, 7.0-7.7 me/100g in subsoil. Soil bacteria density of root zone was the highest in integrated improvement than the other treatments, and it was higher at the harvesting stage than the heading stage. Mean density of microorganism was $61.3{\times}10^5$ in bacteria, $21.5{\times}10^4$ in fungi and actinomycetes was B/F ratio was 28.5 and B/A ratio was 2.9. Vertical root distribution of total and 10cm depth below was more in the integrated improvement and subsoi ling plot than the other plots. Total nitrogen (T-N) content was higher in integrated improvement plot, and phosphate content of leaves was higher in compost and integrated improvement plot, but stem and grain were not different. Potassium content of the plant was higher in integra ted improvement plot. Correlation between dry matter yield and T-N was more significant than the other elements. And the contents of phosphate, calcium and magnesium were significant at 5%, but potassium was not.