Taek Keun Oh

Soil Organic Carbon of Soil Series from 2003 to 2010 in Korea

Soil organic carbon (SOC) of soil series is necessary to calculate soil C sequestration due to IPCC default categorized by climate regions and by soil types. The 3,400 thousand data were downloaded from agricultural soil information system and analyzed to get averages of soil order, soil series, and textual family for the three different soil management practices in Korea. The SOC content was 13.3±5.38 g kg -1 in paddy field, 13.7±7.19 g kg -1 in upland field, and 15.2±8.22 g kg -1 in orchard soil, respectively. As SOC in orchard was 10% greater than that in upland, orchard must be managed with applying compost. The SOCs of inceptisols, which was largely distributed in Korea, were 13.6±5.48 g kg -1 in paddy field, 14.1±7.38 g kg -1 in upland field, and 15.3±8.20 g kg -1 in orchard soil, respectively. The SOCs of alfisols were 13.6±4.96 g kg -1 in paddy field, 13.7±6.99 g kg -1 in upland field, and 15.6±8.59 g kg -1 in orchard soil, respectively. The SOCs of entisols were 11.7±5.16 g kg -1 in paddy field, 12.8±7.05 g kg -1 in upland field, and 13.7±7.81 g kg -1 in orchard soil, respectively. The SOCs of ultisols were 12.7±4.79 g kg -1 in paddy field, 12.7±6.22 g kg -1 in upland field, and 16.3±8.49 g kg -1 in orchard soil, respectively. The fact that soils containing greater clay content in textual family had also more SOC content revealed that SOC could be also dependent on some soil properties as well as soil order. Because SOC differences among soil series representing same textual family were greater than those among textual family, SOC differences should be mainly affected by management practices such as compost application.

Characterization of the pyrolytic solid derived from used disposable diapers

This paper confirms through physical and chemical analyses the possibility to reuse the solid pyrolytic residue derived from used disposable diapers (UDD), heated at different temperatures ranging from 500, 700 and 900°C as a soil amendment. With an increasing pyrolytic temperature, the pH, electrical conductivity, available P2O5, exchangeable K+ and cation exchange capacity tended to increase; however, total-N and exchangeable Ca2+ and Mg2+ decreased. The pyrolytic diaper solid produced at 500°C had a high volatile matter (60.22%) and low ash content (19.10%), which can negatively affect crop growth and productivity when added to soil. Heavy metal concentrations were less than the maximum allowable limits according to Japan standards. The surface of the pyrolytic diaper solid was coarse, porous and heterogeneous with higher temperatures. Hydrogen-containing functional groups, such as OH, C‒H, N‒H and CH2, decreased with increasing pyrolytic temperature. Based on these results, we concluded that the pyrolytic product derived from UDD at higher temperatures offers a potentially effective soil amendment option.