Red spruce soil solution chemistry and root distribution across a cloud water deposition gradient

1992 ◽  
Vol 22 (6) ◽  
pp. 893-904 ◽  
Author(s):  
J.D. Joslin ◽  
M.H. Wolfe

The decline of red spruce (Picearubens Sarg.) at high elevations in eastern North America has been linked in time and space with exposure to acidic cloud water. To investigate the belowground effects of a cloud water deposition gradient between two mature red spruce stands on the summit of Whitetop Mountain, Virginia, the chemistries of precipitation, throughfall, and soil solution were monitored over a 2-year period, and fine-root distributions were characterized. Deposition of water, sulfate, nitrate, and ammonium in throughfall and stemflow was from 15 to 55% greater at the site with greater exposure to cloud water deposition (high cloud site), depending upon the particular ion and year. Soil solution nitrate concentrations were highly variable over time, and base cation, Al, and H ion concentrations were highly correlated with nitrate in both organic and mineral horizons at both sites. Soil solution nitrate, base cation, Al, and H ion concentrations were two to six times greater during periods of low soil moisture in the summer–autumn of 1987 and 1988 than during the remainder of the study period. In the mineral soil solutions, the high cloud site had significantly higher (p < 0.001) concentrations of nitrate and Al, and significantly lower (p < 0.05) Ca:Al and Mg:Al ratios. The high cloud stand also had shallower root systems, with fine-root biomass less than 40% of that of the low cloud stand (p < 0.05) at all depths greater than 18 cm. Soil solutions collected from below 15 cm at the high cloud site had a mean Ca:Al ratio less than 0.5 and Al concentrations that during dry periods, frequently approached or exceeded the literature values for the toxicity threshold for red spruce root growth. Restricted root development in the high cloud stand was apparently the result of this unfavorable chemical environment.

Soil Research ◽  
2001 ◽  
Vol 39 (5) ◽  
pp. 1003 ◽  
Author(s):  
M. L. Adams ◽  
M. R. Davis ◽  
K. J. Powell

The impact of land use change from grassland to conifer forest on the aluminium (Al) concentrations in soils and soil solutions was examined. Soils from grassland were compared with those from adjoining 15–19-year old forest stands at 3 contrasting pairs of sites in South Island, New Zealand. The site pairs were on a terrace [Pinus nigra/P. ponderosa, and grassland (CP)], and a hill slope [Pseudotsuga menziesii and grassland (CF)] in the Craigieburn range, Canterbury, and a hill slope in the Lammerlaw Range, Otago [P. radiata and grassland (LP)]. The sites had never been cultivated or fertilised, and for each pair the forest and grassland were similar in terms of soil and topography. The 1 M KCl exchangeable and 0.02 M CaCl 2 extractable Al levels at 0–10 cm were higher in forest than in grassland topsoil at CP and LP (P < 0.01). In soil solutions there was a trend for both ‘reactive Al’ and Al bound in labile organic complexes to be higher in forest soil at all sites, but site-pair differences were only significant at LP, and only for ‘reactive Al’. The increase in ‘reactive Al’ at this site was linked to the low pH and low base saturation. The ratios of exchangeable and soil solution Ca 2+ and Mg 2+ to ‘reactive Al’ were substantially lower in forest than grassland soils at all sites. Aluminium complexation capacity (Al-CC) values at all sites were higher in forest soil solutions than in grassland soil solutions. For the grassland and forest sites at LP, the Al-CC correlated strongly with the amount of soluble fulvic and humic matter present, as estimated from soil solution UV absorbance at 250 nm. In soils with the lowest percentage base saturation and buffering capacity (LP), afforestation of pastoral grassland with Pinus radiata significantly reduced soil pH and base cation levels, while increasing both soil and soil solution Al concentrations. Under such conditions (base saturation <20%), the increase in ‘reactive Al’ concentrations in soil solutions under fast growing conifer tree species may be sufficient to affect Mg uptake.


1991 ◽  
Vol 21 (6) ◽  
pp. 769-787 ◽  
Author(s):  
Dale W. Johnson ◽  
Helga Van Miegroet ◽  
Steven E. Lindberg ◽  
Donald E. Todd ◽  
Robert B. Harrison

Nutrient distributions, concentrations, and fluxes in two red spruce (Picearubens Sarg.) stands in the Great Smoky Mountains are described and used to evaluate various hypotheses for recent decline of this species. These forests, like others in the southern Appalachians, were relatively rich in N and low in base cation status. The combination of high atmospheric N and S deposition, little or no N or S retention, relatively high N mineralization, and extremely acid soils caused soil solutions to be dominated by NO3−, SO42−, Al, and H+. Soil solution Al in these sites (most of which was in monomeric form) occasionally reached levels noted to inhibit base cation uptake and root growth in solution culture studies. These pulses of Al were driven by pulses of NO3− and, to a lesser extent, SO42− in soil solution. However, fine roots were present at depths of up to 60 cm in the mineral soil, indicating that Al concentrations had not become consistently toxic to roots. Solution fluxes (both throughfall and soil leaching) exceeded litter-fall fluxes for all the macronutrients at both sites, a typical situation for K and S, but most unusual for N, P, Ca, and Mg. There are significant implications of these fluxes and of the apparent net uptake of N by foliage in terms of how vegetation uptake and translocation are calculated. Some new formulations are suggested, but measurement errors in systems with such a predominance of hydrologic fluxes make foliar leaching and, therefore, uptake and translocation calculations extremely uncertain. Although there are no outward signs of decline in these forests (other than balsam fir (Abiesbalsamea (L.) Mill.) mortality due to the balsam woolly adelgid (Adelgespiceae (Ratz.))), the high rates of NO3− leaching rates and the borderline soil solution Al values suggest that these systems are under stress. Whether these factors actually lead to a dieback or growth decline remains to be seen.


1989 ◽  
Vol 19 (6) ◽  
pp. 754-758 ◽  
Author(s):  
Richard M. Klein ◽  
Timothy D. Perkins ◽  
Helen L. Myers

Increased ecosystem loading with inorganic nitrogen compounds derived from anthropogenic sources has been proposed to prolong vegetative growth of spruce, rendering them more susceptible to winter injury. Severely nutrient-deficient 4-year-old red spruce (Picearubens Sarg.) seedlings and adequately fertilized seedlings were provided with synthetic cloud water lacking or containing nitrate, ammonium, or both, for a full growing season, and then exposed to normal winter chilling. Needles from these seedlings were stressed at −25 or −30 °C, and freezing injury was measured as ion leakage. Cloud water condensates had no effect on hardiness of needles of either nutrient status. Initially nutrient-sufficient seedlings transferred to nutrient-deficient conditions also exhibited no change in hardiness. Severely nutrient-deficient seedlings had needles that were significantly more sensitive to winter injury than seedlings under nutrient-sufficient conditions. Improving the nutrient status of initially nitrogen-deficient seedlings reduced their sensitivity to freezing injury. Based upon experimental results and consideration of the amounts of inorganic nitrogen reaching upper-elevation conifer forests, there is no evidence to support the hypothesis that anthropogenic nitrogen supplies significantly reduce winter hardiness of spruce foliage. It is improbable that winter injury due to elevated anthropogenic nitrogen is a causal factor in contemporary forest decline.


1992 ◽  
Vol 22 (2) ◽  
pp. 167-174 ◽  
Author(s):  
N.W. Foster ◽  
M.J. Mitchell ◽  
I.K. Morrison ◽  
J.P. Shepard

Annual nutrient fluxes within two forests exposed to acidic deposition were compared for a 1-year period. Calcium (Ca2+) was the dominant cation in throughfall and soil solutions from tolerant hardwood dominated Spodosols (Podzols) at both Huntington Forest (HF), New York, and the Turkey Lakes watershed (TLW), Ontario. There was a net annual export of Ca2+ and Mg2+ from the TLW soil, whereas base cation inputs in precipitation equaled outputs at HF. In 1986, leaching losses of base cations were five times greater at TLW than at HF. A higher percentage of the base cation reserves was leached from the soil at TLW (5%) than at HF (1%). Relative to throughfall, aluminum concentrations increased in forest-floor and mineral-soil solutions, especially at HF. The TLW soil appears more sensitive to soil acidification. Deposited atmospheric acidity, however, was small in comparison with native soil acidity (total and exchangeable) and the reserves of base cations in each soil. Soil acidity and base saturation, therefore, are likely only to change slowly.


2011 ◽  
Vol 148-149 ◽  
pp. 977-982
Author(s):  
Dao Xi Li

To examine how the dissolved CH4 in soil solution would affect the CH4 emission from rice field, fluxes of CH4 emission were measured by using a manually closed static chamber-gas chromatography method, and the dissolved CH4 in soil solution was obtained through shaking soil solutions, which were extracted from different paddy soil layers by a soil solution sampler with suction and pressure. The results show that the CH4 fluxes from rice fields and the concentration of dissolved CH4 in soil solution are both reduced significantly under the water-saving irrigation as compared to the traditional flooded irrigation. Under the water-saving irrigation, naturally receding water-layer during the early stage leads to an earlier peak of CH4 flux, but dramatically reduces the concentration of dissolved CH4 in soil solution. The maximum concentration is shifted to about 20-cm depth soil layers, and the relationship between CH4 emissions and dissolved CH4 in soil solution can be estimated using an exponential function of dissolved CH4 in soil solution at the depth of about 20 cm (R2=0.89, p4 in soil solution plays a more dominant role in CH4 emission under the water-saving irrigation than that under continuously flooded irrigation.


Tellus B ◽  
1986 ◽  
Vol 38 (5) ◽  
pp. 319-327 ◽  
Author(s):  
Gary M. Lovett ◽  
William A. Reiners

1993 ◽  
Vol 1 (1) ◽  
pp. 38-54 ◽  
Author(s):  
Volker A. Mohnen ◽  
Richard J. Vong

The chemical composition of clouds collected in the eastern United States has been intensely monitored over a 4-year period as part of the Mountain Cloud Chemistry Project. On the basis of these measurements we prepared a climatology for cloud chemistry, using simple statistical analyses tools and incorporating meteorological and cloud physical and chemical information. Five mountain stations have been established for cloud collection covering the northern and southern Appalachian Mountain range: Whiteface Mountain, New York; Mount Moosilauke, New Hampshire; Shenandoah Mountain, Virginia; Whitetop Mountain, Virginia; and Mount Mitchell, North Carolina. This review presents the major result from this 4-year measurement program. Cloud cover and cloud base over the eastern United States were deduced from the global real-time nephanalysis archives produced by the U.S. Air Force, augmented by local observations. Both active and passive cloud collectors were deployed to sample cloud water on an hourly basis, i.e., with sufficient time resolution to resolve synoptic scale phenomena. Chemical analysis of cloud water was performed by a central analytical laboratory with occasional on-site analysis to satisfy quality control procedures. Reliable methods now exist for collecting cloud-water samples in sufficient quantities for detailed chemical analysis. The chemical composition of cloud water varied significantly between sites. However, the differences in cloud-water ion concentration do not necessarily establish a geographic gradient between the sites but rather reflect differences in air-mass trajectories associated with the synoptic air-flow pattern and differences in sample location above cloud base. The dependence of cloud-water ion concentrations on synoptic weather type and observed differences in relative frequencies of warm sector, marine flow, and post-cold frontal synoptic types between northern and southern sites suggest that the north–south differences in cloud-water ion concentrations are related to cloud climatology at the northern sites. When air-mass trajectories shift from southwest to northwest, the concentrations of H+, SO42−, NO3− and NH4+ normally decrease but the southern sites continue to receive high concentrations under northwest flow. The height of cloud-water sample collection above cloud base was found to be an additional source of variability in both cloud-water chemistry and liquid-water content. Seasonal variation in cloud-water chemical composition was investigated at one site only. Sulfate levels were found to be significantly lower in supercooled clouds (i.e., during the 'cold' season) than in 'warm' clouds, but nitrate levels remained about the same.Key words: cloud chemistry, cloud frequency, air-mass trajectories, ANOVA.


Soil Research ◽  
1997 ◽  
Vol 35 (1) ◽  
pp. 183 ◽  
Author(s):  
M. J. McLaughlin ◽  
K. G. Tiller ◽  
M. K. Smart

Fifty commercial potato crops and associated soils were sampled. Soil solutions were extracted from rewetted soils by centrifugation, and solution composition was related to Cd concentrations in tubers. Soils were also extracted with 0·01 M Ca(NO3)2 and 0·01 M CaCl2 solutions, and Cd2+ activities in the extracts were calculated by difference using the stability constants for formation of CdCl2-nn species. The soils had saline solutions (>4 dS/m), and Cl- and SO2-4 in solution markedly affected the speciation of Cd in soil solution, with chloro-complexes, in particular, dominating. While low soil pH was associated with high (>25 nM) concentrations of Cd in soil solution, chloro-complexation also led to high concentrations of Cd in solution, even at neutral to alkaline soil pH values. Tuber Cd concentrations were not related to activities of Cd2+ in soil solution or to activities in dilute salt extracts of soil. Tuber Cd concentrations were related to the degree of chloro-complexation of Cd in solution. The relationship of tuber Cd concentrations to chloro-complexation in soil solution suggests that Cd species other than the free Cd2+ ion are involved in the transport through soil and uptake of Cd by plants.


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