Severely nitrogen deficient pole-stage Corsican pine growing on coastal send dunes were treated over three years with ammonium sulphate, at rates totalling to 0, 252, 504, 1007 and 1510 kg of nitrogen per ha. Over this period the net primary production by the trees rose from 23,000 kg per ha in the untreated plots to a maximum of 47,000 kg per ha in those plots given 1007 kg fertilizer nitrogen per ha. In all treatments root tissues accounted for about 20% and crown tissues for more than 50% of the net primary production, whereas the proportion directed to the stem increased with treatment from 15% to 30%. Nutrient uptake was assessed as the increased quantity accumulated within the trees plus the quantity released through both litter-fall and recreation. Relative to the untreated controls the fastest growing trees showed marked increases in mean annual uptake per ha of nitrogen (16 to 143 kg), phosphorus (4 to 9 kg) and potassium (19 to 57 kg), whereas the mean annual uptake of sodium decreased (45 to 33 kg) and that of both calcium and magnesium remained virtually unchanged ( about 38 and 10 kg respectively). Retention of fertilizer nitrogen occurred in both the tree crop and the soil organic layers but the mineral soil showed no detectable increase in nitrogen content with treatment. The recovery of fertilizer nitrogen in the ecosystem after three years represented, with increasing treatment rate, 100%, 75%, 55% and 45% of the quantity applied over this period.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:635927 |
| Date | January 1969 |
| Creators | Miller, Hugh Graham |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU602337 |
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