Integrated Crop-Livestock Management Effects on Soil Quality Dynamics in a Semiarid Region: A Typology of Soil Change Over Time

Table 4

Mean values of near-surface soil properties within annually cropped and perennial grassland integrated crop-livestock systems in 2002, 2005, and 2008 [18].

Year/change	Annual crop	Perennial grassland
	Soil bulk density (Mg m^−3)
2002		1.02 ± 0.09
2005	1.07 ± 0.12	1.11 ± 0.04
2008	1.16 ± 0.12	1.07 ± 0.06
	+0.09	+0.05
	Electrical conductivity (dS m^−1)
2002	0.24 ± 0.03	0.25 ± 0.04
2005	0.30 ± 0.06	0.29 ± 0.05
2008	0.43 ± 0.12	0.38 ± 0.07
ΔEC	+0.19	+0.13
	Soil pH (−log[H^+])
2002	5.89 ± 0.21	6.46 ± 0.34
2005	6.00 ± 0.33	6.58 ± 0.27
2008	5.95 ± 0.33	6.88 ± 0.24
ΔPH	+0.05	+0.43
	Soil nitrate (mg kg^−1)
2002	6 ± 3	1 ± 1
2005	7 ± 3	1 ± 1
2008	13 ± 8	1 ± 1
ΔNO3N	+6	0
	Soil ammonium (mg kg^−1)
2002	2 ± 1	2 ± 1
2005	2 ± 1	3 ± 1
2008	6 ± 4	4 ± 1
ΔNH4N	+4	+2
	Available P (mg kg^−1)
2002	7 ± 2	9 ± 4
2005	8 ± 4	2 ± 2
2008	14 ± 5	5 ± 1
ΔP	+7	−4
	Potentially mineralizable N (mg kg^−1)
2002	62 ± 14	92 ± 20
2005	70 ± 14	109 ± 12
2008	66 ± 24	117 ± 21
ΔPMN	+4	+25
	Soil organic C (g kg^−1)
2002	29.5 ± 3.8	30.9 ± 4.2
2005	27.1 ± 3.5	26.0 ± 3.8
2008	28.1 ± 6.0	31.9 ± 4.4
ΔSOC	−1.4	+1.0
	Total N (g kg^−1)
2002	2.6 ± 0.3	2.7 ± 0.3
2005	2.4 ± 0.3	2.2 ± 0.3
2008	2.6 ± 0.5	2.8 ± 0.3
ΔTN	0.0	+0.1
	C : N ratio
2002	11.2 ± 0.4	11.4 ± 0.5
2005	11.3 ± 0.4	11.7 ± 0.4
2008	10.9 ± 0.3	11.3 ± 0.3
ΔCN	−0.3	−0.1

deviations are given for each variable in 2002, 2005, and 2008. reflects the difference in soil property between 2008 and 2002.