Comparison of medium-term organic and inorganic fertiliser application on leaf nutrient concentration and yield of maize in rural agriculture in the Mbizana area, Eastern Cape province, South Africa

Figures & data

Table 1:  Pre-trial chemical and physical properties of the experimental soil

Depth (cm)	pH		CEC (cmolc kg^-1)	Extractable acidity^a (cmolc kg^-1)	Acid saturation (%)	Organic C ^b (%)	Total N (%)	P^c (mg kg^-1)	K (cmolc kg^-1)	Ca (cmolc kg^-1)	Mg (cmolc kg^-1)	Na (cmolc kg^-1)	Sand (%)	Silt (%)	Clay (%)
	H2O	KCI
0-30	5.31	4.38	15.75	1.70	45.4	3.85	0.13	4.4	0.14	0.59	1.21	0.10	9.6	52.8	37.6
30-60	5.51	4.56	8.48	0.60	49. 7	1.13	0.05	4.4	0.05	0.18	0.30	0.10	11.3	36.0	52.7
^a 1 M KCl extractable acidity (H+Al)
^b Walkley-Black method
^c Bray 1 extraction

Figure 1:  Fertiliser effects on leaf nutrient concentration and maize grain yield in each growing season. (a) Nitrogen, (b) phosphorus, (c) potassium, (d) calcium, (e) zinc and (f) grain yield

Table 2:  Statistical parameters for plant properties

Source of variation	F ratios and probabilities (p)
	Maize leaf elements
	N	P	K	Ca	Mg	Cu	Fe	Mn	Zn	Grain yield
Season (S)	28.5^***	12.1^**	6.1^*	24.0^***	13.6^***	24.1^***	54.4^***	17.8^***	22.4^***	22.5^***
Treatment (T)	97.7^***	84.0^***	105.6^***	12.2^***	46.3^***	28.2^***	0.5^ns	20.0^***	13.3^***	68.8^***
S×T	22.0^***	6.0^***	4.3^**	2.6^*	3.7^*	6.2^***	0.7^ns	5.1^***	3.0^**	2.5^*
Treatment	Treatment means
	N(g kg^-1)	P(g kg^-1)	K(g kg^-1)	Ca(g kg^-1)	Mg(g kg^-1)	Cu(g kg^-1)	Fe(g kg^-1)	Mn(g kg^-1)	Zn(g kg^-1)	Grain yield(g kg^-1)
CM	21.51^b	2.19^ab	14.84^b	3.75^a	4.85^b	8.5^a	188^a	44.3^b	21.2^ab	2.905^a
CM+N	23.11^a	2.31^a	15.48^b	3.62^a	4.37^b	8.9^a	208^a	48.1^ab	23.5^a	3.104^a
Ftrad	17.43^c	1.39^c	10.93^c	3.90^a	6.0^a	6.3^b	225^a	34.9^c	18.8^b	1.303^b
Frec	23.96^a	2.13^b	16.60^a	3.21^b	3.92^c	9.0^a	208^a	52.2^a	18.5^b	2.880^a
LSD (p = 0.01)	1.15	0.18	0.94	0.33	0.52	0.9	86	6.5	2.5	0.407
Respective treatment column means followed by different letters are significantly different ^* p = 0.05, ^** p = 0.01, ^*** p = 0.001, ns = not significant