Gross nitrogen transformations in harvested and mature aspen-conifer mixed forest soils from the Boreal Plain

Carmosini, Nadia; Devito, K. J.; Prepas, E. E.

doi:10.1016/s0038-0717(02)00172-4

Cited by 39 publications

(37 citation statements)

References 14 publications

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“…Many studies on gross N turnover in high-latitude forest and tundra ecosystems have shown that NH 4 + production seldom exceeds gross N consumption (all processes consuming NH 4 + ) (e.g., Davidson et al 1992;Fisk et al 1998;Fisk and Fahey 2001;Perakis and Hedin 2001;Carmosini et al 2002;Booth et al 2005). This was also found here in the DS and SH, but not in the TH forest type.…”

Section: Discussionsupporting

confidence: 66%

“…The rates of gross N mineralization found in the three forest types (Table 3, Fig. 1) encompassed the variations within Arctic (Fisk et al 1998), temperate, and boreal soils worldwide (Merila¨et al 2002;Fisk and Fahey 2001;Carmosini et al 2002;Perakis and Hedin 2001;Davidson et al 1992;Booth et al 2005). Rates of gross nitrification in the TH forest type were among the higher reported (Booth et al 2005).…”

Section: Discussionmentioning

confidence: 84%

“…Some studies, e.g., Chapin et al (1988) found net N mineralization rates below estimates of plant uptake. This prompted measurements of gross N mineralization and nitrification rates (e.g., Davidson et al 1991Davidson et al , 1992Hart et al 1994a;Stark and Hart 1997;Fisk and Fahey 2001;Carmosini et al 2002;Merila¨et al 2002). The finding of discrepancies between net N mineralization and plant N uptake also stimulated research on uptake of organic N sources (Chapin et al 1993;Kielland 1994;Na¨sholm et al 1998).…”

Section: Introductionmentioning

confidence: 99%

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Contrasting patterns of soil N-cycling in model ecosystems of Fennoscandian boreal forests

et al. 2005

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The low plant productivity of boreal forests in general has been attributed to low soil N supply and low temperatures. Exceptionally high productivity occurs in toe-slope positions, and has been ascribed to influx of N from surrounding areas and higher rates of soil N turnover in situ. Despite large apparent natural variations in forest productivity, rates of gross soil N mineralization and gross nitrification have never been compared in Fennoscandian boreal forests of contrasting productivity. We report contrasting patterns of soil N turnover in three model ecosystems, representing the range in soil C-to-N ratios (19-41) in Fennoscandian boreal forests and differences in forest productivity by a factor close to 3. Gross N mineralization was seven times higher when soil, microbial, and plant C-to-N ratios were the lowest compared to the highest. This process, nitrification and potential denitrification correlated with inorganic, total and microbial biomass N, but not microbial C. There was a constant ratio between soil and microbial C-to-N ratio of 3.7+/-0.2, across wide ratios of soil C-to-N and fungi-to-bacteria. Soil N-cycling should be controlled by the supplies of C and N to the microbes. In accordance with plant allocation theory, we discuss the possibility that the high fungal biomass at high soil C-to-N ratio reflects a particularly high supply of plant photosynthates, substrates of high-quality C, to mycorrhizal fungi. Methods to study soil N turnover and N retention should be developed to take into account the impact of mycorrhizal fungi on soil N-cycling.

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Section: Discussionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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Contrasting patterns of soil N-cycling in model ecosystems of Fennoscandian boreal forests

et al. 2005

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“…However, 15 years after harvest the uncut stands in this study had higher net mineralization rates than the harvested sites. Forest harvesting has increased, decreased or resulted in no change to forest floor and mineral soil horizon ammonification and nitrification rates when compared to unharvested boreal stands (Gordon and Van Cleve, 1983;Walley et al, 1996;Smith et al, 1998Smith et al, , 2000Simard et al, 2001;Carmosini et al, 2002Carmosini et al, , 2003. The results from these studies agree with the main conclusion of Grenon et al (2004) in their examination of forest floor N dynamics in coniferous ecosystems in British Columbia.…”

Section: Introductionsupporting

confidence: 74%

Impact of harvesting and logging slash on nitrogen and carbon dynamics in soils from upland spruce forests in northeastern Ontario

Hazlett

Gordon

Voroney

et al. 2007

Soil Biology and Biochemistry

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The potential impact of timber harvesting in the boreal forest on aquatic ecosystem water quality and productivity depends in part on the production of nutrients within the soil of the harvested catchment. Nitrogen supplied by organic matter decomposition is of particular interest because of the important role that N plays in biotic processes in surface waters, and in forest nutrition in general. Logging slash quality and input to the forest floor has the potential to influence N availability after harvest on clearcut sites. Net production of organic and inorganic-N and microbial biomass C and N concentrations were determined during a 90-day laboratory incubation at constant temperature and moisture. Incubated soils included F horizon and shallow mineral soil horizons (0-5 cm) from unharvested and full-tree harvested (2 and 12 growing seasons since harvest) boreal forest sites at the Esker Lakes Research Area (ELRA), in northeastern Ontario, Canada. In an ancillary experiment, black spruce foliage was added to unharvested forest floor material after 30 days during a 90-day laboratory incubation to simulate the influence of logging slash from full-tree harvesting on C and N dynamics. Twelve-year old clearcut F horizon material released on average 75 and 5 times more NO À 3 -N and 3 and 2 times as much inorganic-N than soil collected from unharvested and 2-year-old clearcuts, respectively. This increase in NO À 3 -N accumulation during the incubation was accompanied by decreases in both exchangeable NH þ 4 -N and microbial biomass C and N levels. Net daily changes in microbial biomass N were significantly related to organic and inorganic-N accumulation or loss within the F horizon. Mineral soil release of inorganic-N was lower than release from the forest floor. Nitrate-nitrogen accumulation was lower, and NH þ 4 -N accumulation was higher in mineral soil from unharvested sites when compared to 12-year-old clearcuts. Calculated harvest response ratios indicated that incubated mineral soil from the 12-year-old clearcut sites released significantly greater amounts of NO À 3 -N than 2-year-old clearcuts. Incorporation of black spruce needles into F horizon material reduced the production of organic and inorganic-N and increased microbial biomass N. Laboratory incubations of F horizon and shallow mineral soil from 12-year-old clearcuts suggested that these boreal soils have the capacity for increased inorganic-N production compared to uncut stands several years after harvesting. This has the potential to increase N availability to growing boreal forest plantations and increase N leaching due to greater NO À 3 -N levels in the forest soil. r

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“…Measurements of tree harvesting effects on gross ammonification, gross nitrification and gross immobilization rates in mineral soils of forest ecosystems are scarce and mostly limited to measurements at single points in time in clear cut stands (Pedersen et al 1999;Carmosini et al 2002;Westbrook and Devito 2004). However, Grenon et al (2004), after finding temporal variability of temperature sensitivity of gross NH 4 + transformation in the forest floor of two clear cut sites, emphasized the necessity of multiple sampling dates for drawing conclusions on ecosystem functioning.…”

Section: Measurements and Errorsmentioning

confidence: 99%

Effects of forest management on soil N cycling in beech forests stocking on calcareous soils

Dannenmann¹,

Gasché²,

Ledebuhr³

et al. 2006

Plant Soil

106

114

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The effects of forest management (thinning) on gross and net N conversion, the balance of inorganic N production and consumption, inorganic N concentrations and on soil microbial biomass in the Ah layer were studied in situ during eight intensive field measuring campaigns in the years 2002-2004 at three beech (Fagus sylvatica L.) forest sites. At all sites adjacent thinning plots (''T'') and untreated control plots (''C'') were established. Since the sites are characterized either by cool-moist microclimate (NE site and NW site) or by warm-dry microclimate (SW site) and thinning took place in the year 1999 at the NE and SW sites and in the year 2003 at the NW site the experimental design allowed to evaluate (1) short-term effects (years 1-2) of thinning at the NW site and (2) medium-term effects (years 4-6) of thinning under different microclimate at the SW and NE site. Microbial biomass N was consistently higher at the thinning plots of all sites during most of the field campaigns and was overall significantly higher at the SWT and NWT plots as compared to the corresponding untreated control plots. The size of the microbial biomass N pool was found to correlate positively with both gross ammonification and gross nitrification as well as with extractable soil NO 3 -concentrations. At the SW site neither gross ammonification, gross nitrification, gross ammonium (NH 4 + ) immobilization and gross nitrate (NO 3 -) immobilization nor net ammonification, net nitrification and extractable NH 4 + and NO 3 -contents were significantly different between control and thinning plot. At the NET plot lower gross ammonification and gross NH 4 + immobilization in conjunction with constant nitrification rates coincided with higher net nitrification and significantly higher extractable NO 3 -concentrations. Thus, the medium-term effects of thinning varied with different microclimate. The most striking thinning effects were found at the newly thinned NW site, where gross ammonification and gross NH 4 + immobilization were dramatically higher immediately after thinning. However, they subsequently tended to decrease in favor of gross nitrification, which was significantly higher at the NWT plot as compared to the NWC plot during all field campaigns after thinning except for April 2004. This increase in gross nitrification at the NWT plot (1.73 mg N kg -1 sdw day -1 versus 0.48 mg N kg -1 sdw day -1 at the NWC plot) coincided with significantly higher extractable NO 3 -concentrations (4.59 mg N kg -1 sdw at the NWT plot versus Ó Springer Science+Business Media B.V. 2006 0.96 mg N kg -1 sdw at the NWC plot). Pronounced differences in relative N retention (the ratio of gross NH 4 + immobilization + gross NO 3 -immobilization to gross ammonification + gross nitrification) were found across the six research plots investigated and could be positively correlated to the soil C/N ratio (R = 0.94; p = 0.005).In sum, the results obtained in this study show that (1) thinning can lead to a shift in the balance of microbial inorganic N production ...

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Gross nitrogen transformations in harvested and mature aspen-conifer mixed forest soils from the Boreal Plain

Cited by 39 publications

References 14 publications

Contrasting patterns of soil N-cycling in model ecosystems of Fennoscandian boreal forests

Contrasting patterns of soil N-cycling in model ecosystems of Fennoscandian boreal forests

Impact of harvesting and logging slash on nitrogen and carbon dynamics in soils from upland spruce forests in northeastern Ontario

Effects of forest management on soil N cycling in beech forests stocking on calcareous soils

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