Short-term effects of nutrient compensation following whole-tree harvesting on soil and soil water chemistry in a young Norway spruce stand

Abstract

A growing demand for bioenergy from conventional forestry in Sweden will increase the need of nutrient compensation, that preferably should be made relatively shortly after harvesting and have no undesired side-effects. This study compared the effects of granulated wood ash (Ash), N-free, dolomite-based fertiliser (Vitality) and the green fraction of harvest residues (Residues) on the podsolic soil and soil solution of a young Norway spruce (Picea abies (L.) Karst) stand in SW Sweden. The treatments were applied three years after clear-felling and whole-tree harvesting. The soil solution was repeatedly sampled in the rooting zone 2-5 years after treatment. The soil study was performed 4 years after the Ash treatment and 3 years after Residues treatment and the last Vitality treatment (the Vitality treatment was applied on two occasions over 2 years). The Vitality treatment increased base saturation and effective CEC in the humus layer in relation to the other treatments, and also increased Ca and K concentrations in the soil solution. The Ash treatment resulted in higher exchangeable K concentration than Vitality in the litter layer, and Residues increased K concentrations in the soil water. No treatment influenced the KCl-exchangeable nitrate concentrations in the soil or the nitrate levels in the soil water. The results indicate that granulated wood ash could be used for long-term nutrient compensation without undesired short-term side-effects.

Spot mounding and granulated wood ash increase inorganic N availability and alter key components of the soil food web in clear-cut Norway spruce forests

“…Our result that granulated ash did not increase soil pH is in agreement with other studies using granulated ash (Rosenberg et al, 2010;Wang et al, 2010) but in contrast to studies using loose or hardened ash (Arvidsson and Lundkvist, 2003;Jokinen et al, 2006;Perkiömäki and Fritze, 2002;Saarsalmi et al, 2001). The low solubility of granulated ash (Nieminen et al, 2005) is one possible reason for the absence of a wood-ash effect on pH in our experiment.…”

“…In contrast to our results, granulated wood ash did not affect the N concentration of spruce needles (Wang et al, 2007) or the NH 4 -N concentration in organic soil (Wang et al, 2007) when wood-ash fertilization was applied 2 years and the response measured 6 years after the seedlings were planted. Different temporal scale may explain the differences between our results and those of Wang et al (2007Wang et al ( , 2010. Our results also conflict with studies showing N concentration of spruce needles to be unaffected by self-hardened ash in 1-4-year-old (Arvidsson and Lundkvist, 2002), by granulated wood ash in 35-65 year-old Norway spruce stands (Jacobson, 2003) and by loose ash in a short-term pot experiment (Nieminen, 2009b), but the ash form and study sites in these studies are not directly comparable with ours.…”

“…The productivity of wood-ash fertilization could be increased if the fertilization was integrated with the establishment of plantations. However, existing reports on the effects of post-harvest wood-ash fertilization (Wang et al, 2007(Wang et al, , 2010 do not cover all ecosystem components. In particular, studies on the interaction of wood ash fertilization and site preparation are lacking.…”

Risk analysis of effects of whole-tree harvesting on site productivity

“…Further, the selection of mitigation measures requires site-specific diagnosis and selection of mitigation treatments (Carter et al, 2006). In addition, the preferred mitigation method depends on the element in question (Wang et al, 2010). This decision-making is even more difficult if several risks of site productivity decline occur on the site simultaneously.…”

Bioenergy grown on contaminated land – a sustainable bioenergy contributor?

“…The nutrient removal can be partly compensated by returning the ashes or other residual products from the energy conversion process [79,80]. The use of branches and tops may even reduce the nutrient leaching and acidification [81] but it may also disturb the kinetics of the natural biogeochemical cycles of many elements if added to naturally acid forest soils [82].…”