Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 8, 1997
Publication Date: N/A
Interpretive Summary: The quantities of flue gas desulfurization (FGD) residues generated by scrubbing the flue gases of coal fired power plants is becoming an ever increasing burden on society. Most of the alfalfa grown in the US is produced on soils deficient in boron (B) a major ingredient of FGD residues. We tested the feasibility of using this waste material in a beneficially and environmentally benign manner for growing alfalfa on a marginally B deficient soil. Our results demonstrated that FGD residue is a readily available B source for alfalfa production, particularly late in the growing season when native soil B availability decreases. It was also shown that residue-borne B did not leach below 6 inches. This information will be used by farmers, consultants, and utility companies to establish managements system to beneficially utilize FGD residue for alfalfa production. State and federal regulator officials will use this information directly as they establish rules and guidelines of applying this waste material onto agricultural lands.
Technical Abstract: Very little literature documents the fate of flue gas desulfurization (FGD) residues under field conditions when applied at agronomic rates. The objective of this study was to document the availability of FGD residue- borne boron (B) for alfalfa (Medicago sativa L.) uptake when applied to marginally B deficient soils. The FGD residue was applied at rates of 0, 0.46 and 3.74 Mg ha**-1 (0.038 and 3.1 kg B ha**-1, respectively) on a sil loam soil immediately prior to alfalfa seeding. Soil pH increased temporarily, but returned to background levels by the end of the first growing season. Alfalfa yields were unaffected by these rates of residue applications. Shoot B concentrations decreased as the growing season proceeded for the control treatment, but second and third cuttings of alfalfa produced on residue amended soil had increased B levels demonstrating that FGD residue was a readily available B source, particularly later in the growing season when native soil B availability decreased. Residue-borne B did not leach below 0.15 m.