Low stream nitrate concentrations associated with oak forests on the Allegheny high plateau of Pennsylvania

Lewis, Gregory P.; Likens, Gene E.

doi:10.1029/2000wr900101

Cited by 27 publications

(15 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The forest drained by Walker Branch is dominated by oaks and streams draining oak forests have been reported to be particularly low in nitrate (Lewis and Likens 2000;Lovett et al 2000). However, Lewis and Likens (2000) argue that the low nitrate concentrations of oak forest streams are likely due to soil physical characteristics or land use history rather than the direct effect of oaks on nitrate losses.…”

Section: Discussionmentioning

confidence: 97%

The importance of in-stream uptake for regulating stream concentrations and outputs of N and P from a forested watershed: evidence from long-term chemistry records for Walker Branch Watershed

2004

View full text Add to dashboard Cite

Long-term, weekly measurements of streamwater nitrogen and phosphorus concentrations in the West Fork of Walker Branch, a 1st order forested stream in eastern Tennessee, were used to assess the importance of in-stream processes for controlling stream concentrations and watershed exports. Over the period from 1991 to 2002, there was a slight declining trend in watershed export of dissolved inorganic N via streamflow, despite relatively high and constant wet N deposition rates (5 kg/ha/y). The watershed retains >90% of N deposition inputs. Concentrations of NO 3 À and soluble reactive phosphorus (SRP) showed distinct seasonal patterns with autumn and early spring minima and summer maxima. An end-member mixing analysis indicated that these seasonal concentration patterns were largely a result of seasonal variations in in-stream uptake processes, with net uptake of NO 3 À and SRP having the greatest impact on streamwater concentrations in November (reductions of 29 lg N/l and 2.5 lg P/l, respectively). This was likely a result of high rates of uptake by microbes colonizing new inputs of leaf detritus. For NO 3 À there was a secondary peak in net uptake in March and April (about 9 lg N/l) resulting from increased uptake by stream algae and bryophytes. Summer was a period of net release of NO 3 À to streamwater (peaking at 9 lg N/l in July) and minimal net effects on SRP concentrations. On average, in-stream processes resulted in removal of about 20% of the NO 3 À and 30% of the SRP entering the stream from the catchment annually. This study, as well as other recent work, suggests that in-stream processes are important buffers on stream nutrient concentrations and exports reducing the effects of changes in inputs and retention in terrestrial portions of watersheds.

show abstract

Section: Discussionmentioning

confidence: 97%

The importance of in-stream uptake for regulating stream concentrations and outputs of N and P from a forested watershed: evidence from long-term chemistry records for Walker Branch Watershed

2004

View full text Add to dashboard Cite

show abstract

“…Low resorption and high litter N of northern red oak was surprising given the high resorption efficiency of chestnut oak and the findings that streams draining watersheds dominated by oak forests generally have lower NO 3 À concentrations than streams in watersheds without oaks (Lovett et al 2000). For example, NO 3 À concentrations in watersheds dominated or codominated by northern red oak in Pennsylvania were 3-7 times less than those dominated by non-oak species (Lewis and Likens 2000). A similar pattern was observed in the Catskill Mountains of New York where streams that drained oak-dominated watersheds had the lowest NO 3 À concentrations, compared to streams that drained watersheds without oaks (Lovett et al 2000).…”

Section: Nitrogen Resorption From Foliagementioning

confidence: 91%

Symptoms of nitrogen saturation in an aggrading forested watershed in western Maryland

et al. 2007

View full text Add to dashboard Cite

The objective of this study was to evaluate the nitrogen (N) biogeochemistry of an 18-22 year old forested watershed in western Maryland. We hypothesized that this watershed should not exhibit symptoms of N saturation. This watershed was a strong source of nitrate (NO 3 À ) to the stream in all years, with a mean annual export of 9.5 kg N ha À1 year À1 and a range of 4.4-18.4 kg N ha À1 year À1 . During the 2001 and 2002 water years, wet deposition of inorganic N was 9.0 kg N ha À1 year À1 and 6.3 kg N ha À1 year À1 , respectively. Watershed N export rates in 2001 and 2002 water years were 4.2 kg N ha À1 year À1 and 5.3 kg N ha À1 year À1 , respectively. During the wetter water years of 2003 and 2004, the watershed exported 15.0 kg N ha À1 year À1 and 18.4 kg N ha À1 year À1 , rates that exceeded annual wet deposition of N by a factor of two (7.5 kg N ha À1 year À1 in 2003) and three (5.5 kg N ha À1 year À1 in 2004). Consistent with the high rates of N export, were high concentrations (2.1-3.3%) of N in foliage, wood (0.3%) and fine roots, low C:N ratios in the forest floor (17-24) and mineral soil (14), high percentages (83-96%) of the amount of mineralized N that was nitrified and elevated N concentrations (up to 3 mg N l À1 ) in soil solution. Although this watershed contained a young aggrading forest, it exhibited several symptoms of N saturation commonly observed in more mature forests.

show abstract

“…Species differences in nitrifi cation rates may be important in determining how effectively forests can either retain atmospheric N deposition or leach N into surface waters. For instance, sugar maple stands are often associated with high rates of net nitrifi cation and nitrate leaching and low N retention (Lovett and Mitchell 2004) while red oak stands often have low rates of net nitrifi cation and nitrate leaching and high N retention (Lewis andLikens 2000, Lovett et al, 2004). This study indicates that the species differences in net nitrifi cation rates are also evident in gross nitrifi cation rates and that the differences are not due to microbial NO 3 − consumption.…”

Section: Discussion Species Effects On Gross and Net Nitrogen Transfomentioning

confidence: 99%

The Influence of Tree Species, Nitrogen Fertilization, and Soil C to N ratio on Gross Soil Nitrogen Transformations

Christenson

Lovett

Weathers

et al. 2009

Soil Science Soc of Amer J

View full text Add to dashboard Cite

To investigate controls on gross N transformations in forest soils, a 15N pool dilution technique was used on soils of single‐species plots of five major tree species (red oak [Quercus rubra L.], sugar maple[Acer saccharum Marsh.], hemlock [Tsuga canadensis (L.) Carr], beech [Fagus grandifolia Ehrh.] and yellow birch [Betula alleghaniensis Britton]) in the Catskill Mountains of New York State. Catskill forest soils had high rates of gross mineralization and NH4+ consumption, indicating rapid NH4+ cycling, a pattern not captured by net N mineralization assays. Sugar maple had the highest rates of gross mineralization and NH4+ consumption. Rates of gross nitrification were similar to rates of net nitrification for all species. Sugar maple had the highest gross nitrification rates, while hemlock and red oak had the lowest rates. There were no significant species differences in NO3− consumption. Fertilization of the plots did not significantly alter N cycling rates with the exception of yellow birch, where N fertilization decreased NO3− consumption. We observed a significant negative relationship between net nitrification and soil C/N ratio in both organic and mineral horizons, but our results indicate that the mechanism underlying that relationship was different in the two horizons. In the mineral horizon, limitation of net nitrification in soils of high C/N ratio probably resulted from low gross NH4+ production. In organic horizons, low NH4+ production was not a significant factor and higher NO3− consumption explained some of the pattern. Understanding the roles individual tree species as well as excess N input play in regulation of the N cycle will improve forest management and prediction of forest responses to elevated N deposition.

show abstract

Low stream nitrate concentrations associated with oak forests on the Allegheny high plateau of Pennsylvania

Cited by 27 publications

References 16 publications

The importance of in-stream uptake for regulating stream concentrations and outputs of N and P from a forested watershed: evidence from long-term chemistry records for Walker Branch Watershed

The importance of in-stream uptake for regulating stream concentrations and outputs of N and P from a forested watershed: evidence from long-term chemistry records for Walker Branch Watershed

Symptoms of nitrogen saturation in an aggrading forested watershed in western Maryland

The Influence of Tree Species, Nitrogen Fertilization, and Soil C to N ratio on Gross Soil Nitrogen Transformations

Contact Info

Product

Resources

About