Journal Article Soil 7440-44-0 Carbon N762921K75 Nitrogen extracellular enzymes Research Support, U.S. Gov't, Non-P.H.S. arbuscular mycorrhizal fungi microbial community nitrogen fertilization plant-microbial interactions N acquisition strategies Research Support, Non-U.S. Gov't below ground carbon allocation belowground carbon allocation carbon cycling ectomycorrhizal fungi experimental N addition metatranscriptomics microbial activity nitrogen mineralization optimal allocation theory plant biomass allocation reduced precipitation soil respiration temperate forest terrestrial carbon sink water stress