Fly Ash and Composted Biosolids as a Source of Fe for Hybrid Poplar: A Greenhouse Study

Table 4

Correlation matrix for 2005 Greenhouse Study showing growth versus soil and foliar parameter. Note: correlation coefficients (𝑟 values) are followed by 𝑃 values; **indicates significance 𝑃<.05; ***indicates significance 𝑃<.001.

	Leaf area	Leaf Wt.	Stem Wt.	Root Wt.	Stem Lnth.	Stem Dia.
Fe soil	−0.08	0.09	0.42***	−0.11	0.33**	0.11
	0.5197	0.4885	0.0006	0.3987	0.0068	0.4026
NO3-N	−0.15	−0.21	−0.45***	−0.08	−0.46***	−0.28**
	0.2364	0.0983	0.0002	0.5246	0.0001	0.0234
pH	−0.04	−0.16	−0.54***	−0.18	−0.41***	−0.14
	0.7443	0.1990	<0.0001	0.1481	0.0007	0.2756
SAR	0.16	−0.04	−0.35**	−0.14	−0.26**	−0.16
	0.2213	0.7499	0.0047	0.2592	0.0389	0.1945
EC	−0.14	0.08	0.24	−0.23	0.27**	−0.04
	0.2900	0.5548	0.052	0.0656	0.0279	0.7498
B leaves	0.21	−0.08	−0.20	0.14	−0.44***	0.03
	0.0982	0.5331	0.1198	0.2605	0.0003	0.7922