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 phytotox ic 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 (Fest uca rubra L,) was compared with 'Bonanza' and 'Kentucky-31' tall fescue (Fe stuca arundinacea Schreb.) and 'Touchdown' Kentucky bluegrass (Poa pratensi s L.) for leaf phytotoxicity symptoms, rapidity of achieving cover, persist ence of cover, and metal accumulation. Biosolids compost more strongly redu ced soluble Zn and Cd, resulting in effective remediation of Zn phytotoxici ty that persisted for the 4 yr of this test. 'Merlin' red fescue showed rem arkable 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. 'Ke ntocky-31' fall fescue plants grew rapidly and reached almost 100% cover wi thin 3 mo in compost treatment plots, but the Zn exceeded phytotoxic thresh old levels (>500 mg Zn kg(-1)). 'Bonanza' tall fescue and 'Touchdown' Kentu cky bluegrass had good growth performance and contained lower concentration s 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 t he biosolids-compost plots. The combination of calcareous soil pH and highe r organic matter, Fe, and phosphate levels of biosolids-compost amended plo ts improved the overall success of vegetation establishment and allowed imp ortant turfgrasses to revegetate highly Zn-contaminated soils.