Nitrogen mineralization and H+ transfers in a Scots pine (Pinus sylvestris L.) forest soil as affected by liming

Abstract

H + production due to N uptake in a mature Scots pine stand subjected to high NH + deposition was previously estimated to amount to approx. 2.2 kmol ha-x y -1. The question whether H + transfers related to N mineralization (ammonification and nitrification) offset or corroborate this proton production is investigated in the present research. To determine N mineralization, soil cores were used of which both ends were closed with layers of ion exchange resin (IER) to prevent influx and efflux of ions. The effect of liming on N mineralization and the resulting H + production was investigated in 7 incubation periods of each ca. 8 wk. Because of its high mobility NO3 accumulated in both IER layers at the expense of that in the incubated forest floor and mineral soil. Net N mineralization in the soil cores as a whole amounted to 40 and 77 kg N ha-l in 384 d in the control and limed plots, respectively. In both treatments ca. 65% of mineralized N was nitrified. H + production due to N mineralization amounted to approx. 1.2 kmol ha-l y -1 in the control and limed plots. Liming reduced the amount of C in the forest floor, but not forest floor mass, because of an increased mixing with mineral particles.

Is tree growth in boreal coniferous stands on mineral soils affected by the addition of wood ash?

“…Nevertheless, the growth results obtained from this study are consistent with earlier studies on wood ash additions (Jacobson 2001(Jacobson , 2003Saarsalmi et al 2004, Moilanen et al 2013. The theory, based on experiences from forest liming, is that the addition of an alkaline compound may influence the supply of inorganic N that is available for tree growth (Persson et al 1989;Arnold et al 1994;Huber et al 2006). Whether the effect is an increase or a decrease in growth is influenced by the pre-treatment N-status of the soil (Persson et al 1991;Booth et al 2005;Pitman 2006).…”

Influence of Tree Roots on Nitrogen Mineralization

“…When using the field incubation methods (Raison et al 1987) to assess N mineralization in the field, several studies (Aber et al 1985, Persson et al 2000, Jussy et al 2000 found high, and probably exaggerated, N mineralization fluxes compared with classical estimates (N in the annual biomass increment plus N in root and leaf litter) at sites with high nitrification, while values were more consistent at poorly nitrifying sites. This may be related to the fact that nitrate formation in the rhizosphere and leaching may be exaggerated when measurements are made several weeks after roots are cut (Arnold et al 1994). …”

Impact of dolomite lime on the ground vegetation and on potential net N transformations in Norway spruce (Picea abies (L.) Karst.) and sessile oak (Quercus petraea (Matt.) Lieb.) stands in the Belgian Ardenne

“…[13]. In contrast, increased net N mineralisation without an increase in the proportion of N nitrified was reported for a sandy Scots pine soil [3]. Kreutzer [21] also found increased nitrification, but located in the mineral layer and linked to increased mineralisation.…”