Mineral Nutrition of Copper‐tolerant Browntop on Metal‐contaminated Mine Spoil

Abstract

AbstractHeavy metal‐tolerant populations of browntop (Agrostis tenuis Sibth.) have been developed on a commercial scale in Britain for largescale restoration of abandoned metalliferous spoils. This study was carried out to clarify those aspects of the mineral nutrition of copper tolerant browntop which optimize its use in reclamation work.The effects of factorial combinations of 0, 50, and 100 kg/ha of nitrogen (N), phosphorus (P), potassium (K), and calcium (Ca as calcium carbonate) on shoot productivity of browntop on a copper‐contaminated mine spoil were examined in a glasshouse experiment. Shoots were harvested after 12 weeks and regrowth after a further 10 weeks.Significant responses at both harvests were obtained to Ca addition, and to 50 and 100 kg/ha N, whilst response to P was significant only up to 50 kg/ha. There was no response to added K.In the absence of P, N did not increase yield. Addition of 50 kg/ha P produced significantly increased yield in the 50 and 100 kg/ha N treatment at both harvests, whilst addition of 100 kg/ha P produced a further significant response at both harvests. Ca × P interaction was negative, but only significant at harvest 2.Addition of P and Ca reduced shoot metal concentrations at both harvests, whilst N addition did so only at harvest 1.The effects of nutrient addition and their differential effects at harvests 1 and 2 reflect the physical and chemical properties of the mine spoil, in particular leaching, heavy metal nutrient complexing, and its acid regeneration potential due to pyrite weathering.