Table 2.

Chemical characteristics of the soil samples

		Hiyoriyama	Amamiya
pH	-	5.9	6.1
Electrical conductivity	dS/m	0.23	0.02
Total organic carbon	g/kg	3	2.4
Total nitrogen	g/kg	0.2	0.2
Ammonium nitrogen (NH3)	mg/kg	19.9	15.9
Nitrate nitrogen (NO${}_3^{-}$)	mg/kg	6.2	84.5
Nitrite nitrogen (NO${}_2^{-}$)	mg/kg	<0.05	<0.05
Effective phosphate (PO${}_4^{3-}$)	mg/kg	12	40
Exchangeable K +	cmol(+)/kg	0.34	0.36
Exchangeable Ca 2+	cmol(+)/kg	6.19	4.32
Exchangeable Mg 2+	cmol(+)/kg	0.44	0.94
Exchangeable Na +	cmol(+)/kg	0.42	0.10
Exchangeable Mn 2+	mg/kg	1.52	3.07
Available iron (Fe)	mg/kg	142	10.4
Cl −	mg/kg	15.7	12.4
Sulfate (SO${}_4^{2-}$)	mg/kg	379	2
Cd a	mg/l	<0.001	<0.001
Cr(VI) a	mg/l	<0.005	<0.005
Total mercury (Hg) a	mg/l	<0.0005	<0.0005
Alkyl mercury (Hg) a	mg/l	<0.0005	<0.0005
Pb a	mg/l	<0.004	<0.004
As a	mg/l	<0.001	0.001
B a	mg/l	<0.1	<0.1
Cd b	mg/kg	<15	<15
Cr(VI) b	mg/kg	<25	<25
Hg b	mg/kg	<1.5	<1.5
Pb b	mg/kg	<15	<15
As b	mg/kg	<15	<15
B b	mg/kg	<400	<400
Cu b	mg/kg	<10	<10
Zn b	mg/kg	100	49
Ni b	mg/kg	<30	<30

^aElution amount of chemicals by water

^bTotal amount of chemicals contained in the soil sample