Tillage Effects on Spatiotemporal Variability of Particulate Organic Matter

Table 3

Effect of standard tillage and no-till on particulate organic matter (POM)-C (BACI^† analysis). All the POM-C fractions were log transformed.

Fraction	Source	DF	Sum of squares	Mean square	𝐹 value	Pr > 𝐹
>1000 𝜇m	Field	1	1.042	1.042	12.94	0.001
	Time	2	1.274	0.637	8.80	0.000
	Field × time	2	0.678	0.339	4.69	0.011
	Location (field)	70	5.639	0.081	1.11	0.294
	Residual	140	10.135	0.072
	Contrast‡
	𝑇0−𝑇1	1			9.30	0.003
	𝑇0−𝑇2	1			1.67	0.199
	Overall means	1			6.28	0.013
250–1000 𝜇m	Field	1	0.832	0.832	37.86	<0.0001
	Time	2	0.351	0.175	10.32	<0.0001
	Field × time	2	0.584	0.292	17.19	<0.0001
	Location (field)	70	1.539	0.022	1.29	0.100
	Residual	140	2.379	0.017
	Contrast
	𝑇0−𝑇1	1			27.71	<0.0001
	𝑇0−𝑇2	1			23.70	<0.0001
	Overall means	1			34.22	<0.0001
53–250 𝜇m	Field	1	0.048	0.048	4.03	0.0487
	Time	2	0.145	0.073	15.97	<0.0001
	Field × time	2	0.260	0.130	28.63	<0.0001
	Location (field)	70	0.831	0.012	2.61	<0.0001
	Residual	140	0.636	0.005
	Contrast
	𝑇0−𝑇1	1			48.79	<0.0001
	𝑇0−𝑇2	1			36.15	<0.0001
	Overall means	1			56.31	<0.0001

^†BACI: Before-After and Control-Impact model.
^‡Difference in the interaction of field and time between August 2003 (𝑇₀), April (𝑇₁), and October 2004 (𝑇₂).