Seasonal partitioning of resource use and constraints on the growth of soil microbes and a forage grass in a grazed Arctic salt-marsh

Hargreaves, Sarah K.Horrigan, Emma J.Jefferies, Robert L.2012-12-292012-12-292009Plant Soil 322 (2009) :279–291http://hdl.handle.net/10315/20472Seasonal growth responses of plants and soil microorganisms to additions of nitrogen (N), phosphorus (P) and carbon (C) were examined in goose-grazed and exclosed plots in an Arctic salt marsh. Plants showed strong growth responses to N and NP additions but not to P. Nitrogen levels in the shoots and roots of Puccinellia phryganodes declined as summer progressed. Microbial biomass was low in spring in spite of N and P additions, likely due to C limitation, but values rose in autumn, independent of nutrient treatment, as dissolved organic carbon (DOC) increased. Glucose addition (C source) elicited a transitory increase in microbial biomass. Multiple plant defoliations by geese had a negative effect on microbial biomass, in spite of the presence of DOC and added N and P, possibly because hypersalinity restricted growth. Plants appear to limit soil inputs of C in summer and compete effectively for resources in contrast to autumn, indicating a temporal partitioning of resources.enmicrobial carbonplant carbonmicrobial and plant carbonnitrogenphosphorusseasonal biomass changesbiomassfertilizerfertilizer additionPuccinellia phryganodesLesser snow geeseLesser snow gooseGrazingHudson Bay coastHudson BaySeasonal partitioning of resource use and constraints on the growth of soil microbes and a forage grass in a grazed Arctic salt-marshArticlehttp://www.springer.com/life+sciences/plant+sciences/journal/11104www.springerlink.comhttp://rd.springer.com/article/10.1007/s11104-009-9915-2