Table 3.

Spatiotemporal variations of irrigation water quality in the Soke irrigation scheme.

		Upstream		Downstream
Parameters	Unit	November	July	November	July	CV (%)
pH	Unitless	6.6	6.5	7.1	6.9	4.1
ECw	dS m−1	0.171	0.170	0.178	0.176	2.1
Ca2+	mg l−1	5	4.7	5	5	2.9
Mg2+	mg l−1	2.6	2.7	2.5	2.6	3.2
K+	mg l−1	6.9	6.8	7.3	6.9	3.2
Na+	mg l−1	21	20	20.5	21	2.3
SAR	Unitless	10.8	10.4	10.6	10.9	2.2
SO42−	mg l−1	0.001	0.002	0.001	0.002	38.5
NO3−	mg l−1	4.4	7.4	5.3	9.2	33
PO43−	mg l−1	0.003	0.05	0.07	0.06	64.8
Fe2+,3+	mg l−1	1.3	1.2	1.5	1.4	8.3
Mn	mg l−1	0.001	0.002	0.001	0.002	23.1
B	mg l−1	0.001	0.002	0.001	0.002	26.6
Cu	mg l−1	0.001	0.001	0.001	0.001	19.2

where CV is the coefficient of variations, and SAR is the sodium adsorption ratio.