Effects of SO2 exposure with nitrogen and sulphur fertilization on the growth of Agropyron smithii.

Published online
01 Jan 1982
Content type
Journal article
Journal title
Journal of Applied Ecology

Milchunas, D. G. & Lauenroth, W. K. & Dodd, J. L. & McNary, T. J.

Publication language
USA & Colorado


A native Montana grassland was exposed to 3-monthly median SO2 concentrations (52, 131 and 228 mu g/m3) and to N, S and N + S fertilization. Leaf area of live and dead material and litter production were measured throughout the growing season. SO2 exposures significantly increased leaf area only in the 52 mu g/m3 SO2 treatment. Av. number of leaves/plant paralleled live leaf area responses to SO2, emphasizing the balance between fertilization and toxicity rather than SO2-enhanced cell division. With N fertilization, growth increased as the level of SO2 increased, indicating that N fertilization can ameliorate the effects of SO2 pollution. Rate of senescence was more rapid and time of senescence was earlier for N-fertilized plants exposed to 228 mu g/m3 SO2 compared with those exposed to 73 or 134 mu g/m3 SO2, but only rate of senescence increased compared with the control. The rate of senescence was more rapid with N fertilization without SO2 compared with the control. No interaction between soil sulphate and SO2 conc. was observed, even though SO4-fertilizer application rates were high.

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