scholarly journals Temporal and spatial variation of nitrogen transformations in nitrogen-saturated soils of a central Appalachian hardwood forest

2001 ◽  
Vol 31 (10) ◽  
pp. 1768-1785 ◽  
Author(s):  
Frank S Gilliam ◽  
Bradley M Yurish ◽  
Mary Beth Adams
Keyword(s):  
Soil Moisture ◽  
Spatial Variability ◽  
Soil Water ◽  
Spatial Patterns ◽  
N Saturation ◽  
Net N Mineralization ◽  
Nitrogen Transformations ◽  
N Dynamics ◽  
Temporal And Spatial ◽  
Nitrogen Additions

We studied temporal and spatial patterns of soil nitrogen (N) dynamics from 1993 to 1995 in three watersheds of Fernow Experimental Forest, W.V.: WS7 (24-year-old, untreated); WS4 (mature, untreated); and WS3 (24-year-old, treated with (NH4)2SO4 since 1989 at the rate of 35 kg N·ha–1·year–1). Net nitrification was 141, 114, and 115 kg N·ha–1·year–1, for WS3, WS4, and WS7, respectively, essentially 100% of net N mineralization for all watersheds. Temporal (seasonal) patterns of nitrification were significantly related to soil moisture and ambient temperature in untreated watersheds only. Spatial patterns of soil water NO3– of WS4 suggest that microenvironmental variability limits rates of N processing in some areas of this N-saturated watershed, in part by ericaceous species in the herbaceous layer. Spatial patterns of soil water NO3– in treated WS3 suggest that later stages of N saturation may result in higher concentrations with less spatial variability. Spatial variability in soil N variables was lower in treated WS3 versus untreated watersheds. Nitrogen additions have altered the response of N-processing microbes to environmental factors, becoming less sensitive to seasonal changes in soil moisture and temperature. Biotic processes responsible for regulating N dynamics may be compromised in N-saturated forest ecosystems.

scholarly journals Effects of Nitrogen on Temporal and Spatial Patterns of Nitrate in Streams and Soil Solution of a Central Hardwood Forest

ISRN Ecology ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Frank S. Gilliam ◽  
Mary Beth Adams
Keyword(s):  
Spatial Heterogeneity ◽  
Soil Water ◽  
Soil Solution ◽  
Spatial Patterns ◽  
N Availability ◽  
Temporal And Spatial Patterns ◽  
Net Mineralization ◽  
Period Data ◽  
Temporal And Spatial ◽  
Nitrogen Additions

This study examined changes in stream and soil water and their relationship to temporal and spatial patterns of in soil solution of watersheds at the Fernow Experimental Forest, West Virginia. Following tenfold increases in stream concentrations over a 13-year period (1969–1981) on untreated WS4, concentrations have declined through 2006. Following fourfold increases in stream on treatment WS3 from pretreatment levels to a 1998 maximum, concentrations have declined through 2006, despite additions of N. Concentrations of soil water were consistently lower for WS4 compared to WS3. Data for soil water on WS3 versus WS4 followed patterns of net mineralization and nitrification for these watersheds. Nitrogen additions to WS3 decreased spatial heterogeneity of N processing, which was largest in the pretreatment year and decreased significantly to a minimum by 2000-2001. Concurrently, soil water increased on WS3 from 1.3 mg -N L−1 in pretreatment 1989 to a maximum of 6.4 mg -N L−1 in 2001. Spatial heterogeneity in soil water on WS4 remained high during this period. Data suggest that temporal patterns of stream may be influenced by spatial heterogeneity of watershed processes which vary over time in response to N availability.

scholarly journals Effects of experimental freezing on soil nitrogen dynamics in soils from a net nitrification gradient in a nitrogen-saturated hardwood forest ecosystem

2010 ◽  
Vol 40 (3) ◽  
pp. 436-444 ◽  
Author(s):  
Frank S. Gilliam ◽  
Adam Cook ◽  
Salina Lyter
Keyword(s):  
N Mineralization ◽  
Soil Freezing ◽  
N Saturation ◽  
Net N Mineralization ◽  
N Dynamics ◽  
Net Nitrification ◽  
Soil Nitrogen Dynamics ◽  
Soil N Cycle ◽  
N Mineralization Potential ◽  
Fernow Experimental Forest

This study examined effects of soil freezing on N dynamics in soil along an N processing gradient within a mixed hardwood dominated watershed at Fernow Experimental Forest, West Virginia. Sites were designated as LN (low rates of N processing), ML (moderately low), MH (moderately high), and HN (high). Soils underwent three 7-day freezing treatments (0, –20, or –80 °C) in the laboratory. Responses varied between temperature treatments and along the gradient. Initial effects differed among freezing treatments for net N mineralization, but not nitrification, in soils across the gradient, generally maintained at LN < ML ≤ MH < HN for all treatments. Net N mineralization potential was higher following freezing at –20 and –80 °C than control; all were higher than at 0 °C. Net nitrification potential exhibited similar patterns. LN was an exception, with net nitrification low regardless of treatment. Freezing response of N mineralization differed greatly from that of nitrification, suggesting that soil freezing may decouple two processes of the soil N cycle that are otherwise tightly linked at our site. Results also suggest that soil freezing at temperatures commonly experienced at this site can further increase net nitrification in soils already exhibiting high nitrification from N saturation.

scholarly journals Temporal and spatial variability of soil moisture based on WSN

2013 ◽  
Vol 58 (3-4) ◽  
pp. 826-833 ◽  
Author(s):  
Man Zhang ◽  
Minzan Li ◽  
Weizhen Wang ◽  
Chunhong Liu ◽  
Hongju Gao
Keyword(s):  
Soil Moisture ◽  
Spatial Variability ◽  
Temporal And Spatial Variability ◽  
Temporal And Spatial

Heterogeneity in soil nitrogen within first-order forested catchments at the Turkey Lakes Watershed

2005 ◽  
Vol 35 (4) ◽  
pp. 797-805 ◽  
Author(s):  
Neil Foster ◽  
John Spoelstra ◽  
Paul Hazlett ◽  
Sherry Schiff ◽  
Frederick Beall ◽  
...  
Keyword(s):  
Soil Water ◽  
Organic N ◽  
Net N Mineralization ◽  
Forested Catchments ◽  
N Dynamics ◽  
Turkey Lakes Watershed ◽  
Topographic Positions ◽  
Lower Slope ◽  
Isotopic Effects

Topographic positional regulation of nitrogen (N) dynamics in soil within Canadian Shield headwaters, located in calibrated catchments containing mature, tolerant hardwood forest, was examined to determine how N pools, mineralization, nitrification, and leaching in soil relate to N export in drainage waters. A uniformly high net N mineralization and nitrification potential for surficial soil layers rich in organic N was demonstrated for ridge, upper-middle slope, and lower slope – footslope topographic positions. Results from plot-scale studies revealed that NO3– concentrations in soil water from well-drained soils were very highly variable throughout the catchments, ranging from 25 to 175 µmol·L–1, with a median of 80 µmol·L–1. The isotopic effects of denitrification were not detected in soil water collected from lower slope – footslopes, and in situ rates of N2O production from soils on lower slope – footslopes and valley bottoms were very low and highly variable. Higher N exports from soils than from streams were not explained by differences in soil water N with topographic position or denitrification in lower landscape topographic positions. Using an average soil water N value, based on the replicated plots within catchments, did not reduce the calculated substantial differences in N export between soils and streams.

Temporal and spatial variability of soil moisture in a forest succession series in Dinghushan

2021 ◽  
Vol 41 (5) ◽  
Author(s):  
刘佩伶，陈乐，刘效东，戴雨航，冯英杰，张倩媚，褚国伟，孟泽 LIU Peiling
Keyword(s):  
Soil Moisture ◽  
Spatial Variability ◽  
Forest Succession ◽  
Temporal And Spatial Variability ◽  
Temporal And Spatial ◽  
Succession Series

scholarly journals Factors Influencing Spatial Variability in Nitrogen Processing in Nitrogen-Saturated Soils

2001 ◽  
Vol 1 ◽  
pp. 505-513 ◽  
Author(s):  
Frank S. Gilliam ◽  
Frank C.C. Somerville ◽  
Frank N.L. Lyttle ◽  
Frank M.B. Adams
Keyword(s):  
Spatial Variability ◽  
N Mineralization ◽  
Forest Floor ◽  
Mineral Soil ◽  
Nitrifying Bacteria ◽  
Saturated Soils ◽  
N Saturation ◽  
Net N Mineralization ◽  
Net Nitrification ◽  
Floor Material

Nitrogen (N) saturation is an environmental concern for forests in the eastern U.S. Although several watersheds of the Fernow Experimental Forest (FEF), West Virginia exhibit symptoms of N saturation, many watersheds display a high degree of spatial variability in soil N processing. This study examined the effects of temperature on net N mineralization and nitrification in N-saturated soils from FEF, and how these effects varied between high N-processing vs. low N-processing soils collected from two watersheds, WS3 (fertilized with [NH4]2SO4) and WS4 (untreated control). Samples of forest floor material (O1 horizon) and mineral soil (to a 5-cm depth) were taken from three subplots within each of four plots that represented the extremes of highest and lowest rates of net N mineralization and nitrification (hereafter, high N and low N, respectively) of untreated WS4 and N-treated WS3: control/low N, control/high N, N-treated/low N, N-treated/high N. Forest floor material was analyzed for carbon (C), lignin, and N. Subsamples of mineral soil were extracted immediately with 1 N KCl and analyzed for NH4+ and NO3-to determine preincubation levels. Extracts were also analyzed for Mg, Ca, Al, and pH. To test the hypothesis that the lack of net nitrification observed in field incubations on the untreated/low N plot was the result of absence of nitrifier populations, we characterized the bacterial community involved in N cycling by amplification of amoA genes. Remaining soil was incubated for 28 d at three temperatures (10, 20, and 30°C), followed by 1 NKCl extraction and analysis for NH4+and NO3-. Net nitrification was essentially 100% of net N mineralization for all samples combined. Nitrification rates from lab incubations at all temperatures supported earlier observations based on field incubations. At 30°C, rates from N-treated/high N were three times those of N-treated/low N. Highest rates were found for untreated/high N (two times greater than those of N-treated/high N), whereas untreated/low N exhibited no net nitrification. However, soils exhibiting no net nitrification tested positive for presence of nitrifying bacteria, causing us to reject our initial hypothesis. We hypothesize that nitrifier populations in such soil are being inhibited by a combination of low Ca to Al ratios in mineral soil and allelopathic interactions with mycorrhizae of ericaceous species in the herbaceous layer.

Effects of fire at two frequencies on nitrogen transformations and soil chemistry in a nitrogen-enriched forest landscape

2004 ◽  
Vol 34 (3) ◽  
pp. 609-618 ◽  
Author(s):  
R EJ Boerner ◽  
J A Brinkman ◽  
Elaine Kennedy Sutherland
Keyword(s):  
Atmospheric Deposition ◽  
Soil Ph ◽  
Fire Suppression ◽  
N Deposition ◽  
Molar Ratio ◽  
Forest Site ◽  
N Saturation ◽  
Net N Mineralization ◽  
Nitrogen Transformations ◽  
N Transformations

This study reports results of the application of dormant-season prescribed fire at two frequencies (periodic (two fires in 4 years) and annual) at four southern Ohio mixed-oak (Quercus spp.) forest sites to restore the ecosystem functional properties these sites had before the onset of fire suppression and chronic atmospheric deposition. Each forest site comprised three contiguous watershed-scale treatment units: one burned in 1996 and 1999, one burned annually from 1996 through 1999, and an unburned control. Soil organic matter, available P, net N mineralization, and nitrification were not significantly changed by fire at either frequency, though values for the latter two properties increased 4- to 10-fold from the period 1995–1997 to the period 1999–2000. Fire at both frequencies resulted in increased soil pH and exchangeable Ca2+. Exchangeable Al3+ was reduced by fire at two of four sites, and the molar ratio of Ca/Al was increased by fire at three of four sites. In contrast to results in most studies of fire, N transformations and availability were not increased by fire in this N-enriched region (deposition of N averaged about 6 kg·ha–1·year–1 over the last 20 years). We hypothesize that the large observed increase in nitrification is an indication of the onset of N saturation. Although fire appears to offset the effect of atmospheric deposition in this region by increasing soil pH, Ca2+, and Ca/Al ratio and reducing available Al3+, increased NO3– fluxes through the soil from continued N deposition may negate the positive effect of fire.

Sign in / Sign up

Export Citation Format

Share Document