Open AccessEffects of long‐term fertilization of forest soils on potential nitrification and on the abundance and community structure of ammonia oxidizers and nitrite oxidizers
Author(s) -
Wertz Sophie,
Leigh Adam K.K.,
Grayston Sue J.
Publication year - 2012
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2011.01204.x
Subject(s) - nitrification , nitrospira , nitrobacter , biology , human fertilization , agronomy , ecology , nitrate , botany , nitrite , chemistry , nitrogen , organic chemistry
Forest fertilization in B ritish C olumbia is increasing, to alleviate timber shortfalls resulting from the mountain pine beetle epidemic. However, fertilization effects on soil microbial communities, and consequently ecosystem processes, are poorly understood. Fertilization has contrasting effects on ammonia‐oxidizing bacteria and archaea ( AOB and AOA ) in grassland and agricultural ecosystems, but there are no studies on AOB and AOA in forests. We assessed the effect of periodic (6‐yearly application 200 kg N ha −1 ) and annual ( c. 75 kg N ha −1 ) fertilization of lodgepole pine and spruce stands at five long‐term maximum productivity sites on potential nitrification ( PN ), and the abundance and diversity of AOB , AOA and N itrobacter and N itrospira ‐like nitrite‐oxidizing bacteria ( NOB ). Fertilization increased AOB and N itrobacter ‐like NOB abundances at some sites, but did not influence AOA and N itrospira ‐like NOB abundances. AOB and N itrobacter ‐like NOB abundances were correlated with PN and soil nitrate concentration; no such correlations were observed for AOA and N itrospira ‐like NOB . Autotrophic nitrification dominated (55–97%) in these forests and PN rates were enhanced for up to 2 years following periodic fertilization. More changes in community composition between control and fertilized plots were observed for AOB and N itrobacter ‐like NOB than AOA . We conclude that fertilization causes rapid shifts in the structure of AOB and N itrobacter ‐like NOB communities that dominate nitrification in these forests.