The maintenance of grassland on smelter wastes in the Lower Swansea Valley. II. Copper smelter waste
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Published source details
Goodman G.T. & Gemmell R.P. (1978) The maintenance of grassland on smelter wastes in the Lower Swansea Valley. II. Copper smelter waste. Journal of Applied Ecology, 15, 875-883.
Published source details Goodman G.T. & Gemmell R.P. (1978) The maintenance of grassland on smelter wastes in the Lower Swansea Valley. II. Copper smelter waste. Journal of Applied Ecology, 15, 875-883.
Summary
Large-scale reclamation trials, using applications of organic materials and pulverized fuel ash, combined with sowing of grasses, aimed at establishment and maintenance on copper smelter waste were set up in the Lower Swansea Valley, Glamorgan (south Wales) in 1965 and monitored until 1970.
Reclamation trials were established in 1965 on copper smelter waste. Separate 0.1 ha areas were treated with ground limestone (at 1,000 kg/ ha) plus either 5 cm sewage sludge, 5 cm screened domestic refuse, pulverised fuel ash (PFA) or not amended further. One of two seed mixtures were sown:
i) common bent-grass Agrostis (capillaris) tenuis, red fescue Festuca rubra, or a more species-rich grass mix was sown on smelter waste treated with sewage sludge, refuse or no amendment;
ii) a grass mixture was sown on waste that had received 7.5, 15 or 22.5 cm of PFA.
After sowing, maintenance treatments (1966 and after) applied were:
i) Annual NPK fertilizer (20 :10:10) at 600 kg/ha, or initial fertilizer only;
ii) Cut once (autumn), or cut twice (June and autumn), and cut grass removed to prevent smothering of the underlying sward;
iii) Soil sprinkling to introduce micro-organisms (spring 1968), or no soil sprinkling.
Yield and species composition: Shoot dry matter production was measured in 96, 4.6 x 0.9 m strips (2 replicates per treatment) in 1966, and 384, 1 x 1 m quadrats (4 replicates per treatment) in 1968 and 1969. Species composition in 1967 and 1969 was determined from herbage samples cut from 0.25 x 0.25 m quadrats (4 replicates per treatment).
Soil analysis: Soil samples were analysed for plant-available copper, zinc, lead, copper, nickel; iron, calcium, magnesium, potassium and phosphate.
Grass growth on most of the treatments declined markedly in 1968 and 1969. Annual applications of fertilizer failed to prevent declines, which were attributed to the recurrence of copper toxicity.
The most successful long term treatment was the 22.5 cm deep covering of PFA, followed by annual NPK fertilizer application. Initial applications of 5 cm layers of sewage sludge, or domestic refuse, or 7.5 and 15 cm layers of PFA, initially gave satisfactory grass cover but failed in the longer term.
Grass sward yield on the 22.5 cm of PFA was maintained during the study period (1966-69), when fertilized annually and cut once each year. This indicates that copper toxicity was completely suppressed by this treatment.
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