Korean soils are classified officially by Soil Taxonomy. Soils in Korea were classified into 7 orders, 14 suborders, 27 great groups, and 390 soil series. The dominant soils in Korea were Inceptisols and Entisols, and Alfisols, Ultisols, Andisols, Mollisols, and Histosols were distributed to a small extent. This study was conducted to reclassify Korean soils based on the second edition of Soil Taxonomy: A Basic System of Soil Classification for Making and Interpreting Soil Surveys. Morphological properties of typifying pedons of 405 soils were investigated and physio-chemical properties were analyzed according to Soil Survey Laboratory Methods Manual of USDA. Alfisols of 44 soils were reclassified; 16 soils were reclassified as Ultisols and 3 soils as Mollisols. Forty Andisols were reclassified; 3 soils were reclassified as other orders. Sixty-four Entisols soils were reclassified; 11 soils were reclassified as Inceptisols, 4 soils as Mollisols, and 3 soils as Andisols. Two hundreds and ten Inceptisols soils were reclassified; 39 soils were reclassified as Alfisols, 21 soils as Ultisols, 13 soils as Mollisols, and 2 soils as Andisols. Twenty-one Inceptisols soils, 16 Alfisols soils, and one Andisols soil were reclassified as Ultisols. As a result of reclassification of Korean soils, Korean soils are now classified into 7 orders, 17 suborders, 39 great groups, 85 subgroups, and 405 soil series. Alfisols and Ultisols are increased remarkably. Sixty Inceptisols soils are reclassified as Alfisols or Ultisols; 44 soils including 30 paddy soils are distributed on fluvio-marine plains, alluvial plaines, local valleys, alluvial fans, and mountain foot slopes. Soils distributed on rolling to hilly areas are mainly developed as Ultisols and some are as Alfisols. Also soils distributed on diluvial terrace are mainly developed as Ultisols and some are as Alfisols. Only two Mollisols soils were developed to a small extent. But 15 soils in Jeju Island and Ulreung Island, 3 soils in limestone areas, and 5 soils in coastal areas are classified as Mollisols. Inceptisols occupied 76.6% and Entisols occupied 12.9% of the whole country. Ultisols and Alfisols occupied only 5.0% and 3.8% respectively. Many soils deveped on rolling to hilly, diluvial terraces, local valleys, mountain foot slopes, etc. are reclassified as Ultisols and Alfisols. As a result Ultisols occupy 12.9% and Alfisols occupy 8.8% of the whole country.
Land suitability assessment for apples and pears was conducted with soil and climate information in South Korea. In doing so, we intended to preserve land and increase the productivity by providing valuable information regarding where more suitable areas for apples or pears are located. We used soil classification driven by soil environmental information system developed by National Institute of Agricultural Science, RDA, and also used climate classification in digital agro-climate map database for which is made by National Institute of Horticultural and Herbal Science. We combined both soil and climate classification results using a most-limiting characteristic method. The combined results showed very similar patterns with the results by classification based on soil information. Such results seem to come from the fact that the classification results by soil relatively lower than those by climate information. The results by soil classification seem to be too downgraded and checking if the final classification ranges in soil are reasonably made is strongly required. Although the most limiting characteristic method had been used widely in land suitability assessment, adapting the method based on results by soil and climate can be influenced by one downgraded factor. Therefore, alternative ways should be carefully considered for increasing the accuracy.
This study was conducted to redetermine the rainfall erosion factor (R factor) in USLE for the estimation of soil loss at Korea. The redetermined R factor may be applied more precisely to interpret the changes of regional/yearly/seasonal patterns, including the amount of rainfall and the kinetic energy of rainfall, in Korea. This study calculated the R factors based on 60-minute precipitation data from 60 sites covering the whole country for 30 years from 1981 to 2010. As a result, the annual mean rainfall was 4,147 MJ mm ha -1 yr -1 hr -1 in Korea. Coastal regions of Jeonnam and Gyeongnam, northwest regions of Gyeonggi, and Seoul had the greater values of R factor compared to other regions. The annual mean R factors for every decade were 3,988, 4,085, and 4,370 MJ mm ha -1 yr -1 hr -1 in 1981~1990, 1991~2000, and 2001~2010, respectively. Generally, the R factors had an increasing tendency over and over pest decades. The ratios of summer R factor to total annual mean R factor were 69.8% (1981~1990), 73.7% (1991~2000), and 74.2% (2001~2010). We found that the absolute values and the relative ratios of summer rainfall are gradually increased.
The Saemangeum reclaimed land has many exposed areas due to the lack of vegetation, and then fugitive dust may be generated by strong winds. To reduce such fugitive dust, barley and reed were tested by various soil management practices (sowing time, irrigation water salt concentration, fertilizer type, fertilizer application method). Summarizing the results are as follows; Wind speeds in the Saemangeum Gwanghwal area in Gimje tend to increase in January -April, decrease in May -August, and slightly increase again in September -December. In particular, strong winds in this area concentrated on March -April. Therefor, it is important to cover the soil surface in March -April. In the first period (April.24 -May.6, 2020) of collecting fugitive dust according to the salt concentration of irrigation water during barley cultivation, 0 dS m -1 and 3 dS m -1 treatment were statistically significant than 6 dS m -1 treatments. However, there was statistically no significant in the 2 nd periods (May.12 -June.28, 2020) and 3 rd periods (June.28 -July.17, 2020) due to the weak wind speed. The effect of reducing fugitive dust by sowing period of barley was statistically significant in the first periods (April.24 -June.6) compared to June and August when the sowing in February, April, October, and December. The 2 nd periods (April.12 -June.28) and 3 rd periods (June.28 -July.17) were also statistically significant compared to the sowing in June and August. And, crop growth by fertilizer type, ammonium sulfate fertilizer treatments (ammonium sulfate, fused super phosphate, potassium sulfate) with sulfate root was better than that of urea treatment (urea, fused phosphate, potassium chloride), even if there was no statistical significance. Between the fertilizer treatment methods in the second periods, soil/soil (basal dressing/top dressing) and soil/foliar had statistically significant compared to foliar/foliar. The effect of reducing fugitive dust between fertilizer types and treating fertilizer methods in reeds was statistically not significant.
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