Sammanfattning

Soil microorganisms are considered C-limited, while plant productivity is frequently N-limited. Large stores of organic C in boreal forest soils are attributed to negative effects of low temperature, soil acidity and plant residue recalcitrance upon microbial activity. We examined microbial activity, biomass and community composition along a natural 90-m-long soil N supply gradient, where plant species composition varies profoundly, forest productivity three-fold and soil pH by three units. There was, however, no significant variation in soil respiration in the field across the gradient. Neither did microbial biomass C determined by fumigation-extraction vary, while other estimates of activity and biomass showed a weak increase with increasing N supply and soil pH. Simultaneously, a phospholipid fatty acid attributed mainly to mycorrhizal fungi declined drastically, while bacterial biomass increased. We hypothesize that low N supply and plant productivity, and hence low litter C supply to saprotrophs is associated with a high plant C supply to mycorrhizal fungi, while the reverse occurs under high N supply. This should mean that effects of N availability on C supply to these functional groups of microbes acts in opposing directions

Nyckelord

boreal forest; carbon supply; microbioal biomass; mycorrhizal fungi; nitrogen availability; saprotrophs; soil sampling; soil pH

Publicerad i

New Phytologist
2003, Volym: 160, nummer: 1, sidor: 225-238
Utgivare: BLACKWELL PUBLISHING LTD

SLU författare

• Högberg, Mona N

  • Institutionen för skogens ekologi och skötsel, Sveriges lantbruksuniversitet
    

• Nordgren, Anders

  • Institutionen för skogsekologi, Sveriges lantbruksuniversitet
    

• Högberg, Peter

  • Institutionen för skogsekologi, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Miljö- och naturvårdsvetenskap


Publikationens identifierare

DOI: https://doi.org/10.1046/j.1469-8137.2003.00867.x

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/114