N, P, and K Budgets and Changes in Selected Topsoil Nutrients over 10 Years in a Long-Term Experiment with Conventional and Organic Crop Rotations

Table 8

Measured changes in selected chemical properties in topsoil (0–25 cm) for the last decade.

Cropping system/year	CA1	CA2	OA	CM	OM1	OM2
	Ignition loss (g 100 g^−1)
1999	6.83	6.88	7.05	7.30	6.98	7.13
2009	6.13	6.70	6.30	6.78	6.50	6.63
Change (2009–1999)	−0.70	−0.18	−0.75	−0.53	−0.48	−0.50
𝑃 value^1	0.054^n.s.	0.608^n.s.	0.204^n.s.	0.152^n.s.	0.265^n.s.	0.088^n.s.
	P-AL (mg 100 g^−1)
1996	5.38	4.00	4.25	4.00	3.75	3.88
2009	7.10	8.23	3.13	6.00	3.00	3.65
Change (2009–1996)	1.73	4.23	−1.13	2.00	−0.75	−0.23
𝑃 value	0.029	0.015	0.036	0.001	0.102^n.s.	0.409^n.s.
	K-AL (mg 100 g^−1)
1996	6.75	6.75	6.13	7.13	6.13	6.00
2009	6.73	12.0	6.35	9.63	6.30	5.55
Change (2009–1996)	−0.03	5.28	0.23	2.50	0.18	−0.45
𝑃 value	0.942^n.s.	0.043	0.362^n.s.	0.022	0.188^n.s.	0.517^n.s.
	K-HNO3 (mg 100 g^−1)
1996	31.1	28.3	30.9	28.6	29.1	26.0
2009	47.8	58.5	39.3	55.5	39.0	35.3
Change (2009−1996)	16.6	30.3	8.38	26.9	9.88	9.25
𝑃 value	0.012	0.007	0.010	0.003	0.001	0.037

¹Level of significance for the pairwise 𝑡-test of differences. Nonsignificance at the 5% level is denoted^n.s.