. 2013 Jan 31;8(1):e55805. doi: 10.1371/journal.pone.0055805

Table 1. ANCOVA results for available nutrients in soil solution.

Variable	Source	d.f.	F-value
Nitrate	Species x Depth x Time	2	1.277^ns
	Species x Depth	2	4.140 ^*
	Species x Time	2	1.606^ns
	Depth x Time	1	30.285 ^***
	Species	2	5.027 ^**
	Depth	1	80.600 ^***
	Time	1	42.499 ^***
	Error	120
Ammonium	Species x Depth x Time	2	0.878^ns
	Species x Depth	2	1.521^ns
	Species x Time	2	0.569^ns
	Depth x Time	1	2.957^ns
	Species	2	0.322^ns
	Depth	1	15.480 ^***
	Time	1	14.675 ^***
	Error	118
Phosphate	Species x Depth x Time	2	0.075^ns
	Species x Depth	2	0.087^ns
	Species x Time	2	0.085^ns
	Depth x Time	1	2.802^ns
	Species	2	0.055^ns
	Depth	1	2.266^ns
	Time	1	40.007 ^***
	Error	117

Diversity of species (F. rubra monoculture, P. lanceolata monoculture and mixture of the two species) and soil depth were fixed factors, and time after plantation was a covariate.

P<0.05;

^**

P<0.01;

^***

P<0.001;

^ns

P>0.09. Bold shows significant effects.