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Harvest residue management and fertilisation effects on soil carbon and nitrogen in a 15-year-old Pinus radiata plantation forest.
- Source :
- Forest Ecology & Management; Aug2011, Vol. 262 Issue 3, p339-347, 9p
- Publication Year :
- 2011
-
Abstract
- Abstract: Growing interest in the use of planted forests for bioenergy production could lead to an increase in the quantities of harvest residues extracted. We analysed the change in C and N stocks in the forest floor (LFH horizon) and C and N concentrations in the mineral soil (to a depth of 0.3m) between pre-harvest and mid-rotation (stand age 15years) measurements at a trial site situated in a Pinus radiata plantation forest in the central North Island, New Zealand. The impacts of three harvest residue management treatments: residue plus forest floor removal (FF), residue removal (whole-tree harvesting; WT), and residue retention (stem-only harvesting; SO) were investigated with and without the mean annual application of 190kgNha<superscript>−1</superscript> year<superscript>−1</superscript> of urea-N fertiliser (plus minor additions of P, B and Mg). Stocks of C and N in the forest floor were significantly decreased under FF and WT treatments whereas C stocks and mass of the forest floor were significantly increased under the SO treatment over the 15-year period. Averaged across all harvesting treatments, fertilisation prevented the significant declines in mass and C and N stocks of the forest floor which occurred in unfertilised plots. The C:N ratio of the top 0.1m of mineral soil was significantly increased under the FF treatment corresponding to a significant reduction in N concentration over the period. However, averaged across all harvesting treatments, fertilisation prevented the significant increase in C:N ratio of the top 0.1m of mineral soil and significantly decreased the C:N ratio of the 0–0.3m depth range. Results indicate that residue extraction for bioenergy production is likely to reduce C and N stocks in the forest floor through to mid-rotation and possibly beyond unless fertiliser is applied. Forest floors should be retained to avoid adverse impacts on topsoil fertility (i.e., increased C:N ratio). Based on the rate of recovery of the forest floor under the FF treatment, stocks of C and N in the forest floor were projected to reach pre-harvest levels at stand age 18–20. While adverse effects of residue extraction may be mitigated by the application of urea-N fertiliser, it should be noted that, in this experiment, fertiliser was applied at a high rate. Assessment of the sustainability of harvest residue extraction over multiple rotations will require long-term monitoring. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 03781127
- Volume :
- 262
- Issue :
- 3
- Database :
- Supplemental Index
- Journal :
- Forest Ecology & Management
- Publication Type :
- Academic Journal
- Accession number :
- 61174711
- Full Text :
- https://doi.org/10.1016/j.foreco.2011.03.040