Soil Phosphorus Dynamics of Wheat-Based Cropping Systems in the Semiarid Region of Argentina

Table 3

Soil organic (Po), inorganic (Pi), and total extractable phosphorus (Pte) in the fine and coarse fraction of different cropping systems (CS).

Year	CS	Fine fraction			Coarse fraction
		mg kg^−1			mg kg^−1
		Po	Pi	Pte	Po	Pi	Pte
0	Ref	60.0	178.0	329.0	129.0	149.0	199.0
9	WG	72.1^b ns	199.8^a*	221.5^b**	5.6^a**	95.2^a**	98.1^a**
	WW	50.0^c ns	98.4^b**	149.7^c**	2.1^a**	73.6^b**	80.2^b**
	WL	88.1^a*	200.8^a*	331.4^a ns	1.2^a**	89.7^a**	85.9^b**
10	WG	127.8^a	149.6^a	305.7^a	6.1^a	81.5^a	91.0^a
	WW	72.2^b	93.8^b	256.3^b	3.3^a	65.2^b	87.8^a
	WL	101.6^a	144.3^a	263.2^ab	5.7^a	86.2^a	76.5^b
11	WG	75.4^a	143.4^a	264.0^a	17.5^a	74.1^b	86.2^a
	WW	75.4^a	121.0^b	239.5^ab	6.8^a	55.3^c	77.3^b
	WL	77.6^a	151.5^a	207.9^b	8.9^a	94.1^a	81.8^ab
12	WG	84.8^a	133.9^b	259.2^a	1.6^a	84.2^a	83.8^a
	WW	57.9^b	150.7^ab	256.6^ab	8.6^a	83.0^a	108.5^b
	WL	89.3^a	161.6^a	199.0^b	4.3^a	88.7^a	81.1^a

, and ns indicate statistical differences , and not significant, respectively, between each treatment sampled in year 9 and reference soil. For each P form different letters indicate differences among treatments in each year.