Impacts of different prescribed fire frequencies on selected soil chemical properties in a semi-arid savannah thornveld

Figures & data

Figure 1. Experimental layout at the University of Fort Hare Research Farm

Table 1. Mean values (mg kg⁻¹) of selected micronutrients and C, N, C:N ratio and P in various burning treatments

Treatment	Zn	Mn	Cu	C (%)	N (%)	C:N ratio	P (mg L^−1)
No burn (control)	1.00 (0.59)^c	44.17 (13.29)^a	2.31 (0.63)^b	1.79 (0.27)^ab	0.21 (0.02)^a	8.53 (0.47)^c	5.00 (1.13)^ab
Sexennial	4.10 (2.31)^a	27.10 (24.36)^a	2.60 (1.20)^b	1.75 (0.32)^ab	0.20 (0.03)^b	8.67 (0.63)^c	4.20 (1.26)^b
Quadrennial	2.74 (1.92)^b	43.50 (29.46)^a	4.23 (1.22)^a	2.01 (0.26)^a	0.20 (0.01)^b	10.11 (1.47)^a	3.83 (0.83)^b
Triennial	3.15 (1.84)^a	36.09(27.47)^a	5.06 (1.95)^a	1.95 (0.20)^a	0.21 (0.02)^a	9.54 (0.61)^ab	6.08 (1.31)^a
Biennial	3.01 (2.49)^ab	41.30 (21.46)^a	2.33 (0.86)^b	1.91 (0.20)^a	0.19 (0.02)^b	9.81 (0.53)^b	5.00 (1.54)^ab
Annual	0.67 (0.35)^c	45.08 (11.40)^a	2.25 (0.33)^b	1.56 (0.28)^b	0.17 (0.02)^b	8.77 (0.70)^bc	4.64 (1.15)^ab
Pr > F	0.000	0.460	0.000	0.001	0.009	0.000	0.001

Mean values followed by different letters within a column were significantly (P < 0.05) different according to Tukey’s HSD and (± sd).

Table 2. Mean values of pH and base cations of various burning treatments

Treatment	pH (KCl)	K (mg kg^−1)	Ca (mg kg^−1)	Mg (mg kg^−1)	Na (mg kg^−1)
No burn (control)	4.77 (0.23)^b	205.00 (69.50)^a	836.46 (70.95)^c	168.67 (18.60)^b	17.18 (5.46)^a
Sexennial	5.11 (0.16)^a	189.86 (94.89)^a	869.00 (99.35)^bc	181.30 (37.25)^b	14.13 (2.27)^a
Quadrennial	5.26 (0.18)^a	218.09 (98.19)^a	986.50 (117.03)^a	194.83 (20.97)^ab	15.19 (4.78)^a
Triennial	5.12 (0.29)^a	233.09 (46.99)^a	949.18 (46.99)^ab	204.08 (30.77)^a	13.69 (0.94)^a
Biennial	5.24 (0.11)^a	211.20 (32.33)^a	918.00 (70.90)^b	181.60 (22.00)^ab	13.11 (1.92)^a
Annual	5.29 (0.12)^a	192.67(26.68)^a	907.42 (82.14)^b	171.67 (16.21)^b	15.07 (5.74)^a
Pr > F	0.000	0.633	0.003	0.008	0.181

Mean values followed by different letters are significantly (P < 0.05) different according to Tukey’s HSD and (± sd).

Table 3. Pearson correlation matrix between various soil chemical properties

Variables	C	N	C:N	P	pH	K	Ca	Mg	Na	Zn	Mn	Cu
C	1
N	0.75**	1
C:N	0.71**	0.06	1
P	0.24*	0.31**	0.01	1
pH	0.04	−0.15	0.22	−0.11	1
K	0.107	0.04	0.11	0.15	0.02	1
Ca	0.49**	0.42**	0.29*	0.36**	0.42**	0.12	1
Mg	0.44**	0.36**	0.28*	0.33**	0.50**	0.01	0.61**	1
Na	−0.14	0.06	−0.29*	−0.08	−0.11	0.11	−0.04	0.09	1
Zn	0.20	0.08	0.22	0.02	0.21	0.16	0.18	0.25*	−0.14	1
Mn	−0.14	−0.07	−0.12	−0.03	−0.06	0.08	0.13	−0.14	0.08	0.01	1
Cu	0.23*	0.11	0.25*	0.12	−0.12	0.05	0.22	0.11	−0.10	0.29*	0.32**	1

**Significant at P < 0.01; *Significant at P < 0.05.