Effect of wood ash and nitrogen fertilization on soil chemical properties, soil microbial processes, and stand growth in two coniferous stands in Finland

Abstract

The aim of our study was to investigate long-term effects of wood ash fertilization, given together with nitrogen, on soil chemical properties, soil microbiological processes related to C and N cycling, and tree growth. The study was carried out in a 31-year-old Scots pine stand and in a 45-year-old Norway spruce stand 15 years after application. The treatments were (1) a control with no ash or nutrient addition, (2) wood ash + N (WAN), and (3) a standspecific fertilization (SSF) formulated on the basis of analyses carried out on needle and soil samples taken from the stand. The SSF treatments included N, Cu and B, and in the spruce stand also P. WAN decreased acidity and increased the extractable Ca, Mg and P concentrations in the organic layer in both stands, but SSF had no effect. The microbial processes reacted more strongly to the treatments in the pine stand, whereas the growth response, although only relatively slight during the third 5-year period after fertilization, was detected only in the spruce stand. WAN increased the NH 4 -N concentrations in the organic layer compared to the control and SSF treatments on both sites. In the pine stand, amount of N in microbial biomass and both the C and net N mineralization rates were significantly higher in the WAN treatment than in the SSF treatment. On both sites net nitrification was negligible in all treatments. Soil microbial biomass, microbial respiration and N availability have been used as indices for assessing the biological activity and health of soil, and these parameters either increased or were not affected by the WAN treatment. Hence, with regard to these parameters there are justifiable grounds for applying wood ash.

Ancient waste pits with wood ash irreversibly increase crop production in Central Europe

“…To our knowledge, such long-term, still detectable, residual effects of wood ash deposition on soil chemical properties have not been reported previously. The large positive effect of wood ash application on soil pH, and concentrations of plant available Ca and Mg, are consistent with results reported by many other authors investigating the use of wood ash as fertilizer and as a liming agent in agriculture and forestry (Mandre et al 2004;Park et al 2004;Sartori et al 2007;Saarsalmi et al 2010). According to a meta-analysis of wood ash forest fertilizer experiments by Augusto et al (2008), the heterogeneity of soil We demonstrated here that the increase in plantavailable P concentration in soil due to wood ash deposition can be detected even after 800 years.…”

“…Furthermore, P compounds in the ash generally have low solubility (apatite formation; Steenari et al 1999) and therefore P can be released slowly, but over a very long time. Furthermore, no irrigation was applied and the study site is in a relatively dry and warm region where leaching of nutrients is substantially slower than in humid and cold Nordic regions, in which a rapid decrease in P and K availability after wood ash application has frequently been recorded (Saarsalmi et al 2010). The continued increased P concentration in the soil is consistent with several studies indicating that ancient human activities irreversibly increase the P concentration in the soil (Koerner et al 1997;Verheyen et al 1999;Dupouey et al 2002;Dambrine et al 2007;Holliday and Gartner 2007;Vojta 2007;Oonk et al 2009).…”

“…The concentration of nutrients in wood ash is dependent on the tree species and on the temperature of wood combustion, and the yield of ash decreases with an increase in combustion temperature because of the evaporation of various elements (Etiégni and Campbell 1991;Misra et al 1993). In wood ash, the average concentration of calcium (Ca) is 15% (ranging from 2.5 to 33%), that of potassium (K) is 2.6% (0.1 to 13%), magnesium (Mg) 1% (0.1 to 3.3%) and phosphorus (P) 0.6% (0.1 to 2.5%; see Campbell 1990;Huang et al 1992;Hytönen 2003;Patterson et al 2004;Pitman 2006;Saarsalmi et al 2010).…”

30-Year effects of wood ash and nitrogen fertilization on soil chemical properties, soil microbial processes and stand growth in a Scots pine stand

“…Wood ash includes base cations (Ca, Mg and K), P and B which are not primarily growth limiting nutrients on mineral soils except for B in eastern Finland (Saarsalmi and Tamminen, 2005). Due to large amount of Ca in ash, a decrease in soil acidity and an increase in base saturation after application of loose wood ash to forested mineral soils have been widely reported (Bramryd and Fransman, 1995;Kahl et al, 1996;Saarsalmi et al, , 2010Ludwig et al, 2002;Brunner et al, 2004;Jacobson et al, 2004).…”

Effectiveness of wood ash containing charcoal as a fertilizer for a forest plantation in a temperate region

“…Although wood ash contains low amounts of available N, it can exert a considerable influence on the N cycle, favouring N mineralization in soils rich in organic matter (Saarsalmi et al 2010). The application of ash containing charcoal has the potential to modify the N dynamics through different mechanisms, some working in opposite directions (Clough and Condron 2010).…”