Title: Physicochemical Properties of Topsoil Used for River Improvement and Non-Improvement Areas
Abstract: This study was carried out to evaluate the physicochemical properties and perform a feasibility analysis of planting material composed of topsoil from river improvement and non-improvement areas. The results showed that the physicochemical properties of topsoil from river improvement areas were on the average sandy loam~loamy sand in soil texture, 5.6~6.8 in pH, 0.01~0.06 dS/m in EC, 0.9~2.1% in OM, 0.02~0.12% in T-N, 8~14 <TEX>$cmol^+/kg$</TEX> in CEC, 0.01~0.08 <TEX>$cmol^+/kg$</TEX> in Ex. <TEX>$K^+$</TEX>, 2.55~11.11 <TEX>$cmol^+/kg$</TEX> in Ex. <TEX>$Ca^{2+}$</TEX>, 0.34~2.06 <TEX>$cmol^+/kg$</TEX> in Ex. <TEX>$Mg^{2+}$</TEX>, and 3~396 mg/kg in Av. <TEX>$P_2O_5$</TEX>. And non-improvement areas showed on average sandy clay loam~sand in soil texture, 5.7~6.7 in pH, 0.02~0.08 dS/m in EC, 0.9~4.4% in OM, 0.02~0.23% in T-N, 7~18 <TEX>$cmol^+/kg$</TEX> in CEC, 0.01~0.08 <TEX>$cmol^+/kg$</TEX> in Ex. <TEX>$K^+$</TEX>, 3.81~12.67 <TEX>$cmol^+/kg$</TEX> in Ex. <TEX>$Ca^{2+}$</TEX>, 0.60~1.95 <TEX>$cmol^+/kg$</TEX> in Ex. <TEX>$Mg^{2+}$</TEX>, and 3~171 mg/kg in Av. <TEX>$P_2O_5$</TEX>. Meanwhile, the results of an applied valuation of topsoil- based planting were as follows. Ex. <TEX>$K^+$</TEX> levels were low grade in all survey areas. OM was low grade in 12 improvement areas and 11 non-improvement areas. Av. <TEX>$P_2O_5$</TEX> levels were low grade in 10 improvement areas and 10 non-improvement areas. T-N was low grade in six improvement areas and four non-improvement areas. Ex. <TEX>$Mg^{2+}$</TEX> levels were low grade in two improvement areas.