title: Foliage litter quality and annual net N mineralization: comparison across North American forest sites.
abstract: The feedback between plant litterfall and nutrient cycling processes plays a major role in the regulation of nutrient availability and net primary production in terrestrial ecosystems. While several studies have examined site-specific feedbacks between litter chemistry and nitrogen (N) availability, little is known about the interaction between climate, litter chemistry, and N availability across different ecosystems. We assembled data from several studies spanning a wide range of vegetation, soils, and climatic regimes to examine the relationship between aboveground litter chemistry and annual net N mineralization. Net N mineralization declined strongly and non-linearly as the litter lignin:N ratio increased in forest ecosystems (r2= 0.74, P < 0.01). Net N mineralization decreased linearly as litter lignin concentration increased, but the relationship was significant (r2= 0.63, P < 0.01) only for tree species. Litterfall quantity, N concentration, and N content correlated poorly with net N mineralization across this range of sites (r2< 0.03, P = 0.17-0.26). The relationship between the litter lignin:N ratio and net N mineralization from forest floor and mineral soil was similar. The litter lignin:N ratio explained more of the variation in net N mineralization than climatic factors over a wide range of forest age classes, suggesting that litter quality (lignin:N ratio) may exert more than a proximal control over net N mineralization by influencing soil organic matter quality throughout the soil profile independent of climate.
authors.affiliation: Department of Forest Sciences, Colorado State University, Fort Collins, CO, USA Rocky Mountain Forest and Range Experiment Station, U.S. Forest Service, Fort Collins, CO, USA, , , , , , US.
authors.forename: Neal A
authors.initials: NA
authors.lastname: Scott
authors.affiliation: Department of Forest Sciences, Colorado State University, Fort Collins, CO, USA Rocky Mountain Forest and Range Experiment Station, U.S. Forest Service, Fort Collins, CO, USA, , , , , , US.
authors.forename: Dan
authors.initials: D
authors.lastname: Binkley
keywords: Climate; Forests and grasslands; Key words Litter quality; Lignin:N ratio; Nitrogen mineralization