Effects of water and nutrient applications in a Scots pine stand to tree growth and nutrient cycling

Abstract

In a Scots pine forest stand, demineralized water and a complete set of nutrients with water were applied to the soil by means of frequent irrigation for four years in order to eliminate water and nutrient shortage of the trees. Apart from this optimization, dissolved (NH4)2SO4 was irrigated at a rate of 120 kg N ha-1 y-l to create a situation of N excess. Effect of treatments on tree growth and chemical composition of soil water and vegetation were monitored. From the first treatment year onwards basal area growth increased by ca. 35% as a result of the increased water supply. Nutrient applications increased K and P concentrations in pine needles immediately, but growth was enhanced only in the fourth treatment year and coincided with an improved K supply. Most of the applied P and K was retained in the soil, and only 6% was recovered in the vegetation. Tree nutrient status did not respond on Ca and Mg applications, whereas Ca and Mg seepage losses were increased with ca. 5 kg ha-1 y -t . The applied NH4 was mostly retained in the 0 -20 cm surface soil and caused a drastic increase of A1 in soil solution. Tree growth was stimulated initially by extra NH4, but was hampered after three years obviously because of a decreased P nutrition. The applied base cations were absorped to the soil and the accompanying anions were leached, thus temporarily increasing the acidification of the soil solution.

Effects of high nitrogen load on growth, photosynthesis and nutrient status of Cryptomeria japonica and Pinus densiflora seedlings

“…Several studies have reported that soil acidification is caused by high load by NH 4 + -N, but not by NO 3 --N ( Rollwagen and Zasoski 1988;Wilson and Skeffington 1994a;De Visser and Van Breemen 1995). Several studies have reported that soil acidification is caused by high load by NH 4 + -N, but not by NO 3 --N ( Rollwagen and Zasoski 1988;Wilson and Skeffington 1994a;De Visser and Van Breemen 1995).…”

Reappraisal of drying and wetting effects on C and N mineralization and fluxes in soils

“…The few field studies on this topic mostly simulated reduced rainfall (Hanson et al, 2003;Davidson et al, 2004;Yahdjian et al, 2006;Sotta et al, 2007) or single, extreme drought periods followed either by natural wetting or artificial wetting (Borken et al, 1999(Borken et al, , 2006Emmett et al, 2004). Other approaches are the experimental increase in precipitation that allows the evaluation of natural drought events (Bloem et al, 1992;Matson et al, 1992;De Visser & van Breemen, 1995;Hanson et al, 2003) or the analysis of field observations (e.g. Jarvis et al, 2007).…”

Nitrate leaching in coniferous forest ecosystems: The European Field‐Scale Manipulation Experiments NITREX (Nitrogen Saturation Experiments) and EXMAN (Experimental Manipulation of Forest Ecosystems)

“…increased the nitrate concentration in soil water. For instance, at Harderwijk the mean flux-weighted nitrate concentration increased from 173 mmolc m -3 in the control plot to 398 mmolc m -3 in the irrigated plot [De Visser and Van Breemen, 1995]. This increase can only be explained by an increase in net mineralization, especially because the dilution effect by the increased water availability would have decreased the concentration.…”