Extractable Al and Soil Solution Ionic Concentrations in Strongly Leached Soils from Northwest Iberia: Effects of Liming

Table 2

Values of pH, sum of bases (SB), and cation exchange capacity (CEC), and contents of clay, total organic carbon (SOC), amounts of aluminium and iron extracted by acidified ammonium oxalate (Alo and Feo), by sodium pyrophosphate (Alp and Fep), and extractable iron by dithionite-citrate-bicarbonate (Fed), and values of the Alo/Alp and SOC/Alp molar ratios in studied soils.

Pedon	Hor	Depth (cm)	pH		SB	CEC	Clay	SOC	Alo	Feo	Fed	Alp	Fep	Alo/Alp	SOC/Alp
			H2O	1 M KCl	(cmolc kg^−1)		(g kg^−1)
	Umbrisols
1	Ah1	0–20	4.6	3.8	0.75	28.70	160	63	5.28	9.60	17.21	5.17	5.40	1.02	27.42
	Ah2	20–45	4.9	4.0	0.37	31.14	130	56	6.70	8.15	17.91	6.97	5.25	0.96	18.08
2	Ah1	0–15	4.7	3.8	0.42	15.61	160	43	3.74	6.89	12.31	4.00	6.12	0.94	24.19
	Ah2	15–35	4.8	4.1	0.25	19.54	110	41	6.60	3.47	7.21	5.10	2.70	1.29	18.09
3	Ah1	0–20	4.9	3.4	0.65	20.25	140	70	4.53	2.78	4.74	4.57	2.61	0.99	34.46
	Ah2	20–40	5.0	3.9	0.47	21.92	150	65	6.06	2.81	9.50	4.90	2.67	1.24	29.85
4	Ah1	0–20	4.8	3.7	0.45	12.41	70	50	1.57	0.81	2.44	1.83	0.86	0.86	61.48
	Ah2	20–45	5.1	3.8	0.24	12.08	80	36	4.60	0.71	2.94	3.60	0.82	1.28	22.50
	Cambisols
5	Ah	0–15	4.7	4.0	0.28	15.74	160	64	5.63	5.50	15.95	4.99	3.27	1.13	28.86
	A/B	15–30	4.7	4.1	0.18	25.09	180	52	5.37	7.05	18.42	5.36	4.38	1.00	21.83
6	Ah1	0–15	4.6	3.8	0.24	23.31	140	56	7.45	6.38	18.53	5.31	3.44	1.40	23.73
	A/B	15–30	4.7	4.2	0.15	27.73	140	50	6.88	5.96	16.45	6.01	4.79	1.14	18.72
	Luvisols
7	Ah	0–15	5.2	4.0	1.31	5.60	150	8	0.35	0.65	3.90	0.51	0.60	0.69	35.29
	Bt	15–30	4.9	4.1	0.57	5.88	230	3	0.49	0.77	7.81	0.53	0.58	0.85	12.74
8	Ah	0–20	5.0	3.7	0.77	4.42	50	4	0.24	0.97	12.32	0.34	0.24	0.71	26.47
	Bt	20–35	5.3	3.8	3.18	8.75	140	3	0.41	1.71	12.47	0.59	0.40	0.69	11.44
	Regosols
9	Ah1	0–15	4.8	4.0	0.14	9.70	80	37	5.45	2.36	11.06	4.36	1.56	1.25	19.09
	Ah2	15–30	5.0	4.2	0.18	30.48	210	80	12.42	5.52	18.34	10.09	4.03	1.23	17.84
10	Ah	0–20	4.5	3.8	0.31	17.47	140	73	6.86	3.40	10.22	5.61	2.57	1.22	29.28
	C1	20–40	5.0	4.7	0.15	13.27	80	22	4.20	0.65	5.53	3.96	0.56	1.06	12.50
11	Ah	0–20	5.1	4.0	0.42	6.95	120	27	2.44	1.08	5.91	2.22	0.68	1.10	27.36
	A/C	20–45	5.1	4.3	0.07	4.58	130	6	1.85	0.41	5.64	1.20	0.41	1.54	11.25