Soil nitrogen affects phosphorus recycling: foliar resorption and plant–soil feedbacks in a northern hardwood forest

Abstract

Previous studies have attempted to link foliar resorption of nitrogen and phosphorus to their. respective availabilities in soil, with mixed results. Based on resource optimization theory, we hypothesized that the foliar resorption of one element could be driven by the availability of another element. We tested various measures of soil N and P as predictors of N and P resorption in six tree species in 18 plots across six stands at the Bartlett Experimental Forest, New Hampshire, USA. Phosphorus resorption efficiency (P < 0.01) and proficiency (P = 0.01) increased with soil N content. to 30 cm depth, suggesting that trees conserve P based on the availability of soil N. Phosphorus resorption also increased with soil P content, which is difficult to explain basdd on single-element limitation, butfollows from the correlation between soil N and soil P. The expected single-element relationships were evident only in the 0 horizon: P resorption was high where resin-available P was low in the Oe (P < 0.01 for efficiency, P < 0.001 for proficiency) and N resorption was high where potential N mineralization in the Oa was low (P < 0.01 for efficiency and 0.11 for proficiency). Since leaf litter is a principal source of N and P to the 0 horizon, low nutrient availability there could be a result rather than a cause of high resorption. The striking effect of soil N content on foliar P resorption is the first evidence of multiple-element control on nutrient resorption to be reported from an unmanipulated ecosystem.

Phosphorus limitation of aboveground production in northern hardwood forests

“…Increased RBAI in response to N addition were consistent with pre‐treatment observations of high N resorption by white birch foliage in young stands (See et al. ). Thus, white birch appeared to be limited primarily by N at age 20–25 yr and by P at age 30–40 yr, suggesting the possibility of a shift in nutrient limitation early in succession, which provides tentative support for predictions of the MEL model of N limitation in early stages of recovery post‐harvest (Rastetter et al.…”

“…While it may be surprising that a species with conservative traits such as beech showed the strongest response to P addition in mature forests, this pattern is consistent with pre‐treatment observations of greater P conservation by beech via foliar resorption compared to other species in mature stands (See et al. ).…”

Resource stoichiometry and the biogeochemical consequences of nitrogen deposition in a mixed deciduous forest

“…, See et al. ), and thus the onset of P limitation may be delayed in forests where most of the P demand is met by this recycling pathway.…”

Increasing temperature reduces the coupling between available nitrogen and phosphorus in soils of Chinese grasslands

“…Some data showed that increased N inputs led to increases in both foliar N and P39, and the increasing uptake of N encouraged the absorption and utilization of soil P, resulting in a loss of soil P114041. Moreover, enriched soil N availability generally reduces plant N resorption while P resorption could be less affected (or even promoted)3942, leading to more N relative to P being returned to the soil through plant litter production. Meanwhile, plant litter P was difficult to breakdown because it existed in the form of phospholipid and phytate which must be processes by specialized enzymes and are affected by multiple factors43.…”