The influence of defoliation intensity, season and leaf age on radiocaesium concentration in Agrostis Capillaris

Salt, C.A., Kay, J.W. and Woolsey, J.M. (1997) The influence of defoliation intensity, season and leaf age on radiocaesium concentration in Agrostis Capillaris. Journal of Applied Ecology, 34(5), pp. 1177-1189. (doi:10.2307/2405230)

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Abstract

1. The effects of defoliation intensity, time of year and leaf age on the appearance of '37Cs in shoots of Agrostis capillaris were studied in a pot experiment using topsoil from a peaty podzol, artificially contaminated with '37Cs. Grazing was simulated by frequent clipping to establish swards 3 and 6cm tall. Above-ground biomass was harvested on 10 dates from June to December and separated into five categories of leaf age. 2. Significant differences in growth rate and '37Cs activity concentrations were mea sured between swards clipped to different heights. These differences were not con sistent over time, but did indicate that during the main growing season 137Cs in actively growing tissues was higher in the less intensively defoliated plants. 3. The effects of season and leaf age were pronounced, with activity concentrations of 137Cs increasing rapidly in all living tissues from mid-July onwards and generally stabilizing during autumn; this occurred sooner in actively growing than in fully mature and dying tissues. In autumn, mature and dying tissues had higher con tamination compared to younger tissues; the opposite was the case in summer. Dead leaves always had the lowest '37Cs activity concentrations, up to five times lower than green leaves. Over the winter, a 29% decrease in contamination of plant biomass was measured. 4. The '37Cs activity concentrations in plant material clipped to maintain constant sward height were considerably higher than those in the remaining standing biomass. Since the clippings are the part of the sward most likely to be consumed by grazing animals, animals in the field would be ingesting the most contaminated part of the sward. 5. Seasonal patterns of 37Cs contamination of vegetation are discussed in relation to climatic, soil and plant intrinsic factors.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Kay, Dr James
Authors: Salt, C.A., Kay, J.W., and Woolsey, J.M.
College/School:College of Science and Engineering > School of Mathematics and Statistics > Statistics
Journal Name:Journal of Applied Ecology
Publisher:British Ecological Society
ISSN:0021-8901
ISSN (Online):1365-2664

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