TY - JOUR

T1 - Long-Term Change in the Biogeochemical Cycling of Atmospheric Selenium: Deposition to Plants and Soil.

AU - Haygarth, P. M.

AU - Cooke, A. I.

AU - Jones, K. C.

AU - Harrison, A. F.

AU - Johnston, A. E.

PY - 1993

Y1 - 1993

N2 - Retrospective analysis of archived soil and herbage samples from Rothamsted Experimental Station, southeast England, has determined the long-term changes in selenium deposition over the last century. Three out of four soils (those under permanent grassland, or growing wheat and barley) accumulated Se at a rate of circa 0.15% yr−1 (rate based on Se concentration, normalized to the earliest date circa 100 years earlier), with a net flux in the order 60–90 μg m−2 yr−1. The increase in soil growing root crops was smaller, with an increase of only 0.07% yr−1, possibly reflecting larger volatilization losses from this soil. Herbage samples were sensitive to changes in air composition. In the earlier half of the twentieth century there was an increase in the selenium content of herbage, probably from increased atmospheric deposition following increased use of fossil fuels. However, following the Clean Air Act (1956) the atmospheric loading of Se at this UK site appears to have declined, with contemporary Se concentrations in herbage considerably lower than they were in the 1970s, probably reflecting a change in fossil fuel usage from coal to oil and gas. The atmosphere has been a significant source of Se to plants and therefore grazing livestock. If the decline in the atmospheric input of selenium to herbage continues, selenium deficiency in livestock may become more prevalent in areas where soil concentrations are marginal.

AB - Retrospective analysis of archived soil and herbage samples from Rothamsted Experimental Station, southeast England, has determined the long-term changes in selenium deposition over the last century. Three out of four soils (those under permanent grassland, or growing wheat and barley) accumulated Se at a rate of circa 0.15% yr−1 (rate based on Se concentration, normalized to the earliest date circa 100 years earlier), with a net flux in the order 60–90 μg m−2 yr−1. The increase in soil growing root crops was smaller, with an increase of only 0.07% yr−1, possibly reflecting larger volatilization losses from this soil. Herbage samples were sensitive to changes in air composition. In the earlier half of the twentieth century there was an increase in the selenium content of herbage, probably from increased atmospheric deposition following increased use of fossil fuels. However, following the Clean Air Act (1956) the atmospheric loading of Se at this UK site appears to have declined, with contemporary Se concentrations in herbage considerably lower than they were in the 1970s, probably reflecting a change in fossil fuel usage from coal to oil and gas. The atmosphere has been a significant source of Se to plants and therefore grazing livestock. If the decline in the atmospheric input of selenium to herbage continues, selenium deficiency in livestock may become more prevalent in areas where soil concentrations are marginal.

U2 - 10.1029/93JD01023

DO - 10.1029/93JD01023

M3 - Journal article

VL - 98

SP - 16769

EP - 16776

JO - Journal of Geophysical Research: Atmospheres

JF - Journal of Geophysical Research: Atmospheres

SN - 0747-7309

IS - D9

ER -