A decennial control of N-cycle in the Belgian Ardenne forest ecosystems

Abstract

As a rule, N-supply of mature Ardenne forest ecosystems is satisfactory. Mineralization rates of soil organic matter are generally high and nitrogen is not a frequent nor an important growth limiting factor. Light N-deficiency is likely to depend on unsatisfactory root absorbing power in very acid soils with dysmoder humus. For other major elements, especially for Mg, Ca and P, near optimal nutrition is rarely observed.During the late sixties, fertilizer experiments have shown that nutrition equilibrium of stands growing on acid soils, poor in exchangeable Mg, is very sensitive to artificial NH4-addition. Mg-deficiency symptoms have been induced. The present continuing atmospheric NH 4 input is believed to produce similar but lasting nutritional stress which might be accentuated by additional acidity generated during nitrification of excess NH 4. Evolving Mg deficiency leads to trees' death and developing forest decline is likely to enhance N-output under NO3-form.Awaiting adequate air purification, fertilizing should restore nutrition equilibrium in order to save damaged stands, to slow down soil acidification and to incorporate excess atmospheric N-input into improved biomass production.

Regional scale effects of base cation fertilization on Norway spruce and European beech stands situated on acid brown soils: soil and foliar chemistry

“…The foliar yellowing of Norway spruce associated with forest dieback was identified as a symptom of magnesium deficiency [9,37]. It has been postulated that these deficiencies could be reinforced by acid and nitrogen inputs from the atmosphere, which accelerate the processes of soil acidification and cation leaching [35]. In South Belgium, several studies demonstrated that besides the well known cases of low concentrations in phosphorous and calcium, magnesium was also at a critical level in 70% of the sampled soils [17].…”

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

“…Soil acidification due to atmospheric pollution, and subsequent nutritional deficiencies, appeared to be a major cause of the observed decrease in forest health. This was especially confirmed for Norway spruce growing on naturally poor acidic soils of the Belgian Ardenne [35,36]. For Q. robur and Q. petraea, many studies revealed that the decline should be considered as a complex-causal phenomenon [15,16,23].…”

Responses of European forest ecosystems to 21st century climate: assessing changes in interannual variability and fire intensity

“…In densely populated countries such as the Netherlands, Germany or Belgium, the forests are often restricted to the most infertile soils. In those conditions, nitrogen deposition induces soil base cation depletion and tree nutritional imbalances (De Vries 1988, Schulze 1989, Weissen et al 1990). Otherwise, in regions where water deficit gets worse, rising CO2 concentration offsets the effects of increasing summer drought.…”