Growth and Cadmium Phytoextraction by Swiss Chard, Maize, Rice, Noccaea caerulescens, and Alyssum murale in Ph Adjusted Biosolids Amended Soils.

Past applications of biosolids to soils at some locations added higher Cd levels than presently permitted. Cadmium phytoextraction would alleviate current land use constraints. Unamended farm soil, and biosolids amended farm and mine soils were obtained from a Fulton Co., IL biosolids management facility. Soils contained 0.16, 22.8, 45.3 mg Cd kg–1and 43.1, 482, 812 mg Zn kg–1respectively with initial pH 6.0, 6.1, 6.4. In greenhouse studies, Swiss chard(Beta vulgaris var. cicla), a Cd-accumulator maize (inbred B37Zea mays) and a southern France Cd-hyperaccumulator genotype ofNoccaea caerulescenswere tested for Cd accumulation and phytoextraction. Soil pH was adjusted from ∼5.5–7.0. Additionally 100 rice (Oryza sativa) genotypes and the Ni-hyperaccumulator Alyssum murale were screened for potential phytoextraction use. Chard suffered phytotoxicity at low pH and accumulated up to 90 mg Cd kg–1on the biosolids amended mine soil. The maize inbred accumulated up to 45 mg Cd kg–1with only mild phytotoxicity symptoms during early growth at pH > 6.0.N. caerulescensdid not exhibit phytotoxicity symptoms at any pH, and accumulated up to 235 mg Cd kg–1in 3 months. ReharvestedN. caerulescensaccumulated up to 900 mg Cd kg–1after 10 months. Neither Alyssum nor 90% of rice genotypes survived acceptably. BothN. caerulescensand B37 maize show promise for Cd phytoextraction in IL and require field evaluation; both plants could be utilized for nearly continuous Cd removal. Other maize inbreds may offer higher Cd phytoextraction at lower pH, and mono-cross hybrids higher shoot biomass yields. Further, maize grown only for biomass Cd maximum removal could be double-cropped. [ABSTRACT FROM PUBLISHER]