Phosphorus leaching risk from black soil increased due to conversion of arid agricultural land to paddy land in northeast China

Chemical and Biological Technologies in Agriculture

Table 2 Soil TP, Olsen-P and leachable P distribution with profile depth under arid agricultural soils and paddy soils

Land use	Profile depth	TP	Olsen-P	Leachable P
Land use	(cm)	(mg kg⁻¹)
Arid agricultural soils	0–20	1423.9 ± 656.3a^†	85.3 ± 53.4a**	2.80 ± 3.87a**
	20–40	1081.0 ± 361.5ab	45.7 ± 41.8b**	0.78 ± 1.10b**
	40–60	870.1 ± 547.9b	30.1 ± 22.0c	0.38 ± 0.83bc*
Paddy soils	0–20	949.1 ± 291.3a	34.1 ± 10.2a**	0.10 ± 1.56a**
	20–40	783.6 ± 196.1a	19.6 ± 9.4b**	0.03 ± 0.03b**
	40–60	557.5 ± 103.9b	25.4 ± 7.0c	0.08 ± 0.05a*
Analysis of variance (P value)
Land use		0.003	< 0.001	< 0.001
Profile depth		0.007	< 0.001	< 0.001
Land use × profile depth		0.788	< 0.001	< 0.001

^†Means ± SD followed by a different lowercase letter indicate significant difference from different profile depth in the same land use
*, **indicate significant difference in the same soil depth between arid agricultural soils and paddy soils at p < 0.05 and p < 0.01, respectively