Table 1.

The information on the sampling site.

Sampling Site	Sampling Number	Land Use Type	Main Plant	Longitude	Latitude	Interval (cm)	Depth (cm)	Visible Characteristic of Soil
TS1	22	Agricultural land	Rice	101°58′34″	14°56′32″	10	0–210	Gray, clay
TS2	10	Woodland	Oak	104°56′14″	14°33′05″	5	0–18	Humus layer
							18–45	Brown, red, sand
TS3	20	Abandoned agricultural land	Once planted rice	105°10′48″	15°09′00″	5	0–12	Black, humus layer, a few roots
							12–47	Pale yellow
							47–100	Pale yellow, iron rust
							>100	Fe-Mn nodule
TS4	97	Abandoned agricultural land	Once planted rice	104°55′12″	15°04′12″	2	0–20	Gray-black, humus layer
							20–30	Gray, silty sand
							30–40	White, silty sand
							40–65	Yellow soil, silty sand
							65–100	Yellow, a little iron rust
							100–112	Yellow, much Fe-Mn nodule
TS5	81	Agricultural land	Rice	104°24′00″	14°58′48″	5	0–80	Pale yellow, a little roots
							80–105	Gray, iron rust
							105–160	Gray-green, a little Fe-Mn nodule
							160–205	Fe-Mn nodule
							205–290	Gray-green, clay
TS6	10	Woodland	Teak (Tetona grandis), ceiba (Bombax anceps)	104°30′36″	15°11′59″	5	0–45	A thick fallen leaves layer above the soil