A Comparison of the Short-Term Dynamics of Soil “Damage” Due to Enhanced Nitrogen Deposition As Ammonium Sulphate Or Nitric Acid
Titel:
A Comparison of the Short-Term Dynamics of Soil “Damage” Due to Enhanced Nitrogen Deposition As Ammonium Sulphate Or Nitric Acid
Auteur:
White, Catherine C. Cresser, Malcom S.
Verschenen in:
Chemistry & ecology
Paginering:
Jaargang 15 (1999) nr. 4 pagina's 291-309
Jaar:
1999-01-01
Inhoud:
An experiment has been conducted to contrast the effects of enhanced oxidised and reduced nitrogen deposition upon key chemical parameters in a Calluna moorland podzol. A 40 cm deep podzol profile, derived from granite, was reconstructed in one hundred 4.2 cm diameter cores. for 20 weeks, the cores were subjected twice weekly to simulated rainfall containing either twice ambient nitrogen deposition in Aberdeen, or further enhanced nitrogen (further 2- and 6-fold increases) as nitric acid or ammonium sulphate. to quantify the dynamics of soil change in each horizon, randomly selected cores were destructively analysed every two weeks and the soils analysed. Increased nitrogen inputs, regardless of form, substantially and immediately reduced surface soil pHwater via the mobile anion or salt effect. for the higher nitrogen treatments, the pH reduction was seen throughout the profile. Longer term soil acidification was also seen in the pHcalcium chloride results over the 20 weeks. at a given nitrogen deposition rate, the effects of ammonium sulphate and nitric acid on soil pHcalcium chloride were similar. the ammonium sulphate treatments were especially effective at reducing base saturation throughout much of the profile, the direct base cation leaching being associated with substantial ammonium accumulation. the results suggest that the direct base cation leaching caused by ammonium deposition needs to be considered when assessing atmospheric pollution “damage” to heathland soils.
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