Soil Nitrogen Dynamics
233
In calcareous soils nitrate can make a larger contribution to the mineral N
nutrition of holm oak than in our silicate soils. For instance, in the holm oak
forest at Puechabon near Montpellier (southern France), the net N mineralization was 28-70 kg N ha- I year-I, and 57% of it was nitrified (Merzouki et al.
1990).
In summary, the mesic Montseny site had a substantially higher availability of soil N than its xeric counterpart at Prades. As we will see in Chapter 18,
this difference has at most a moderate effect on the respective forest nutrient
cycles. Despite the differences in N availability, the losses of nitrate leached
out to streams were very low at both sites, revealing that both ecosystems
keep the tight N cycle characteristic of undisturbed forests. A root trenching
experiment in the Montseny site clearly demonstrated the major role that N
uptake by tree roots has in maintaining this tight cycle in holm oak forests
(Bonilla and Roda 1989, 1990). Disturbances such as clear-cutting and burning (Chap. 22) may increase nitrate leaching from the soil in holm oak forests
(Sect. 22.6), though nutrient uptake by regrowing vegetation contributes to
limit nitrogen losses.
References
Attiwill PM, Leeper GW (1987) Forest soils and nutrient cycles. Melbourne University Press.
Carlton, Victoria
Avila A (1988) Balan.;: d'aigua i nutrients en una conca d'alzinar del Montseny. Estudis i Monografies 13, Diputaci6 de Barcelona, Barcelona
Avila A, Bonilla D, Roda F, Pinol J, Neal C (1995) Soilwater chemistry in a holm-oak (Quercus
i/ex) forest: inferences on biogeochemical processes for a montane Mediterranean area.
J HydroI166:15-35
Berg B, Ekbohm G (1983) Nitrogen immobilization in decomposing needle litter at variable carbon:nitrogen ratios. Ecology 64:63-67
Binkley D, Matson P (1983) Ion exchange resin bag method for assessing forest soil nitrogen
availability. Soil Sci Soc Am J 47:1050-1052
Bonilla D, Roda F (1989) Dimimica del nitr6geno en el suelo de un encinar montano: respuesta
a una perturbaci6n experimental. Options Medit Ser Semin 3:187.190
Bonilla D, Roda F (1990) Nitrogen cycling responses to disturbance: trenching experiments in
an evergreen oak forest. In: Harrison AF, Ineson P, Heal OW (eds) Nutrient cycling in terrestrial ecosystems. Elsevier, London, pp 179-189
Bonilla D, Roda F (1992) Soil nitrogen dynamics in a holm oak forest. Vegetatio 991100:247-257
Casals P, Romanya J, Cortina J, Fons J, Bode M, Vallejo VR (1995) Nitrogen supply rate in Scots
pine (Pinus sylvestris L.) forests of contrasting slope aspect. Plant Soil 169:67-73
Cole DW, Rapp M (1981) Elemental cycling in forest ecosystems. In: Reichle DE (ed) Dynamic
properties of forest ecosystems. Cambridge University Press, Cambridge, pp 341-409
Cortina J, Romanya J, Vallejo V R (1995) Nitrogen and phosphorus leaching from the forest
floor of a mature Pinus radiata stand. Geoderma 66:321-330
Davidson EA, Hart SC, Firestone MK (1992) Internal cycling of nitrate in soils of a mature coniferous forest. Ecology 73: 1148-1156
DeBano LF, Eberlein GE, Dunn PH (1979) Effects of burning on chaparral soils: I. Soil nitrogen.
Soil Sci Soc Am J 43:504-509
233
In calcareous soils nitrate can make a larger contribution to the mineral N
nutrition of holm oak than in our silicate soils. For instance, in the holm oak
forest at Puechabon near Montpellier (southern France), the net N mineralization was 28-70 kg N ha- I year-I, and 57% of it was nitrified (Merzouki et al.
1990).
In summary, the mesic Montseny site had a substantially higher availability of soil N than its xeric counterpart at Prades. As we will see in Chapter 18,
this difference has at most a moderate effect on the respective forest nutrient
cycles. Despite the differences in N availability, the losses of nitrate leached
out to streams were very low at both sites, revealing that both ecosystems
keep the tight N cycle characteristic of undisturbed forests. A root trenching
experiment in the Montseny site clearly demonstrated the major role that N
uptake by tree roots has in maintaining this tight cycle in holm oak forests
(Bonilla and Roda 1989, 1990). Disturbances such as clear-cutting and burning (Chap. 22) may increase nitrate leaching from the soil in holm oak forests
(Sect. 22.6), though nutrient uptake by regrowing vegetation contributes to
limit nitrogen losses.
References
Attiwill PM, Leeper GW (1987) Forest soils and nutrient cycles. Melbourne University Press.
Carlton, Victoria
Avila A (1988) Balan.;: d'aigua i nutrients en una conca d'alzinar del Montseny. Estudis i Monografies 13, Diputaci6 de Barcelona, Barcelona
Avila A, Bonilla D, Roda F, Pinol J, Neal C (1995) Soilwater chemistry in a holm-oak (Quercus
i/ex) forest: inferences on biogeochemical processes for a montane Mediterranean area.
J HydroI166:15-35
Berg B, Ekbohm G (1983) Nitrogen immobilization in decomposing needle litter at variable carbon:nitrogen ratios. Ecology 64:63-67
Binkley D, Matson P (1983) Ion exchange resin bag method for assessing forest soil nitrogen
availability. Soil Sci Soc Am J 47:1050-1052
Bonilla D, Roda F (1989) Dimimica del nitr6geno en el suelo de un encinar montano: respuesta
a una perturbaci6n experimental. Options Medit Ser Semin 3:187.190
Bonilla D, Roda F (1990) Nitrogen cycling responses to disturbance: trenching experiments in
an evergreen oak forest. In: Harrison AF, Ineson P, Heal OW (eds) Nutrient cycling in terrestrial ecosystems. Elsevier, London, pp 179-189
Bonilla D, Roda F (1992) Soil nitrogen dynamics in a holm oak forest. Vegetatio 991100:247-257
Casals P, Romanya J, Cortina J, Fons J, Bode M, Vallejo VR (1995) Nitrogen supply rate in Scots
pine (Pinus sylvestris L.) forests of contrasting slope aspect. Plant Soil 169:67-73
Cole DW, Rapp M (1981) Elemental cycling in forest ecosystems. In: Reichle DE (ed) Dynamic
properties of forest ecosystems. Cambridge University Press, Cambridge, pp 341-409
Cortina J, Romanya J, Vallejo V R (1995) Nitrogen and phosphorus leaching from the forest
floor of a mature Pinus radiata stand. Geoderma 66:321-330
Davidson EA, Hart SC, Firestone MK (1992) Internal cycling of nitrate in soils of a mature coniferous forest. Ecology 73: 1148-1156
DeBano LF, Eberlein GE, Dunn PH (1979) Effects of burning on chaparral soils: I. Soil nitrogen.
Soil Sci Soc Am J 43:504-509