The effects of moisture content at tillage on soil strength in maize production

Figures & data

Table 1 Textural composition of surface and sub-surface soils.

Treatments	0–15 cm				15–30 cm
	Sand	Silt	Clay	Texture	Sand	Silt	Clay	Texture
	g/kg				g/kg
C	700	210	90	S L	680	250	70	SL
MC1	770	160	70	SL	740	220	40	LS
MC2	750	180	70	SL	710	230	60	SL
MC3	780	17 0	50	LS	770	200	30	LS
MC4	780	140	80	LS	710	220	70	SL

S L = Sandy Loam, LS = Loamy Sand.

Where, C = control, MC₁, MC_2, MC₃ and MC₄ are 19, 16, 14 and 13% moisture contents respectively.

Table 2 Bulk densities (g/cm³) at 0–15 cm soil depth for the early seasons of 2008 and 2009.

Treatments	Bulk density (g/cm^3)
	First cropping		Second cropping
	Db1	Db2	Db3	Db4
C	1.45a	1.45a	1.22a	1.36a
MC1	1.52a	1.56a	1.36a	1.30a
MC2	1.48a	1.47a	1.16a	1.34a
MC3	1.59a	1.55a	1.37a	1.35a
MC4	1.56a	1.40a	1.30a	1.39a
Mean	1.52	1.49	1.28	1.35

Means along the same column followed by the same alphabets are not significantly different at (P ≤ 0.05) according to Duncan’s Multiple Range Test.

Where, C = control, MC₁, MC_2, MC₃ and MC₄ are 19, 16, 14 and 13% moisture contents respectively. Db₁: Bulk density at 4th week in the first cropping season, Db₂: Bulk density at 8th week in the first cropping season. Db₃: Bulk density at 4th week in the second cropping season. Db₄: Bulk density at 8th week in the second cropping season.

Fig. 1 Effects of moisture content on soil strength.

Table 3 Effect of moisture content at tillage on soil saturated hydraulic conductivity, Ks, (cm/h).

Treatments	First season	Second season	Mean
	(cm/h)
C	21.60a	32.40a	28.80
MC1	18.00a	10.80a	15.48
MC2	10.80a	9.72a	5.40
MC3	3.60a	11.16a	7.20
MC4	21.61a	9.36a	15.84

Means within the same column followed by the same alphabets are not significantly different at P ≤ 0.05 according to Duncan’s Multiple Range Test.

Where, C = control, MC₁, MC_2, MC₃ and MC₄ are 19, 16, 14 and 13% moisture contents respectively.

Fig. 2 Effect of moisture content at tillage on average grain yield of maize for the two cropping seasons.

Table 4 Correlation matrix for selected soil physical properties and maize grain yield.

	Db1	Db2	Db3	Db4	K_1st	K_2nd	Y1st	Y2nd	CI_5	CI_10
	(g/cm^3)				(cm/h)		(t/ha)		(MPa)
Db1 (g/cm^3)	1.00
Db2 (g/cm^3)	0.26	1.00
Db3 (g/cm^3)	0.27	0.59^**	1.00
Db4 (g/cm^3)	0.10	0.27	0.22	1.00
K_1st (cm/h)	0.43	0.01	0.16	0.07	1.00
K_2nd (cm/h)	−0.24	0.24	0.14	−0.13	0.05	1.00
Yd_1st (t/ha)	−0.01	−0.26 0.03	−0.40	0.10	0.33	1.00
Yd_2nd (t/ha)	0.37	−0.19	−0.13–0.50^**	0.21	−0.12	0.41	1.00
CI_5 (MPa)	−0.26	0.31	0.07	0.39	−0.40	−0.27	−0.64^**	−0.34	1.00
CI_10 (MPa)	0.09	0.57^**	0.29	0.26	−0.05	−0.11	−0.51^**	−0.21	0.67^**	1.00

^* and ^** significant at 0.05 and 0.01 level of probability.

Where, Y 1st: Yield of the first cropping season; Y 2nd: Yield of the second cropping season; CI_5: Crust resistance for 0–5 cm soil depth; CI_10: Crust resistance for 5–10 cm soil depth; K_1st: First saturated hydraulic conductivity in the first cropping season; K_2nd: Second saturated hydraulic conductivity in the second cropping season.