Nitrogen leaching and ectomycorrhizal nitrogen retention capacity in a Norway spruce forest fertilized with nitrogen and phosphorus

• To estimate the production of external ectomycorrhizal mycelia (EMM) in Norway spruce forests with varying nitrogen (N) and phosphorus (P) levels, and to relate this to the N retention capacity of ectomycorrhizal fungi (EMF) and N leaching. Seasonal changes in EMF production (in ingrowth mesh bags) and soil water N (in suction lysimeters) were analyzed after fertilization with N or N combined with P. The EMF N retention capacity was estimated by the addition of isotopically labeled N to the mesh bags. No relationship was found between the seasonal variation in EMF growth and N leakage from the soil. However, in the mesh bags, the total assimilation of N-15 by EMF was almost halved by N fertilization, while twice as much N-15 leached through. We found a high specific N assimilation capacity per unit weight of EMF mycelia. This was unaffected by N fertilization, but the total assimilation of N by EMF was drastically reduced due to reduced production of EMM. However, N-retaining processes other than N assimilation by EMF must be taken into account to explain the losses of N after fertilization.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Skogsvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Forest Science (hsv//eng)

Nyckelord

leaching

Nitrogen retention

Phosphorus

Ectomycorrhiza

Nitrogen

Mycelium

Norway spruce

Forestry and Wood Technology

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