Response of four turfgrass cultivars to limestone and biosolids-compost amendment of a zinc and cadmium contaminated soil at Palmerton, Pennsylvania

Revegetation treatments (NPK fertilizer, limestone plus NPK fertilizer, or composted iron-rich limed biosolids) were evaluated on severely Zn phytotoxic soils near a former smelter, Soils contained 15 500 mg Zn and 158 mg Cd kg(-1) and initial soil pH was 6,0. Zinc resistant Merlin' red fescue (Festuca rubra L,) was compared with 'Bonanza' and 'Kentucky-31' tall fescue (Festuca arundinacea Schreb.) and 'Touchdown' Kentucky bluegrass (Poa pratensis L.) for leaf phytotoxicity symptoms, rapidity of achieving cover, persistence of cover, and metal accumulation. Biosolids compost more strongly reduced soluble Zn and Cd, resulting in effective remediation of Zn phytotoxicity that persisted for the 4 yr of this test. 'Merlin' red fescue showed remarkable exclusion of Zn and Cd (201-446 mg kg-l Zn and 0.9-2.7 mg kg(-1) Cd in dry shoots from treated plots) but grew slowly and made poor lawns. 'Kentocky-31' fall fescue plants grew rapidly and reached almost 100% cover within 3 mo in compost treatment plots, but the Zn exceeded phytotoxic threshold levels (>500 mg Zn kg(-1)). 'Bonanza' tall fescue and 'Touchdown' Kentucky bluegrass had good growth performance and contained lower concentrations of Zn and Cd than 'Kentucky-31' tall fescue on biosolids-compost amended treatments and were more suitable as a lawn and/or revegetation crop. After the first year of the study, the commercial turfgrasses survived only on the biosolids-compost plots. The combination of calcareous soil pH and higher organic matter, Fe, and phosphate levels of biosolids-compost amended plots improved the overall success of vegetation establishment and allowed important turfgrasses to revegetate highly Zn-contaminated soils.