Applied and Environmental Soil Science

Research Article

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

Table 2

Soil NO₃-N, P, and Fe a Doak sandy loam after amending with Fe EDDHA + UAN (urea ammonium nitrate), fly ash + UAN, and composted biosolids ( per treatment). Means with the same letter are not significantly different at level.


	Fe	NO₃-N	P
Treatments	(mg kg⁻¹)	(mg kg⁻¹)	(mg kg⁻¹)

Control	4.44 d	2.3 c	9.39 d
Fe EDDHA + UAN	4.84 d	3.4 a	8.55 d
ACB DTPA	16.63 c	2.4 c	23.23 c
ACB 22.75	22.13 b	2.5 bc	30.71 b
ACB 44.5	37.09 a	3.3 ab	52.05 a
FA 22.75 + UAN	5.27 d	3.8 a	8.87 d
FA 44.5 + UAN	5.51 d	3.5 a	8.90 d
FA DTPA + UAN	6.48 d	3.7 a	8.59 d

Mean	12.80	3.1	18.79
LSD	3.28	0.82	2.56
Value	104.09	4.64	306.1
Pr	<.0001	0.0004	<.0001

Codes for biosolid treatments are referenced the following way: ACB 22.75, ACB 44.5 (for Albuquerque composted biosolids at 22.75 Mg ha⁻¹ and 44.5 Mg ha⁻¹ application rates, resp.), ACB DTPA (biosolids applied at a rate based upon its DTPA extractable, plant-available Fe; equivalent to 14 Mg ha⁻¹). Codes for fly ash plus urea ammonium nitrate fertilizer treatments are referenced as FA 22.75 + UAN, FA 44.5 + UAN, and FA DTPA + UAN (fly ash applied at a rate based upon its DTPA extractable, plant-available Fe; equivalent to 74 Mg ha⁻¹). The Fe EDDHA plus urea ammonium nitrate fertilizer treatment is referenced as Fe EDDHA + UAN.