Effect of variable-retention harvesting on soil nitrogen availability in boreal mixedwood forests

2006 ◽  
Vol 36 (11) ◽  
pp. 3029-3038 ◽  
Author(s):  
Lucie Jerabkova ◽  
Cindy E Prescott ◽  
Barbara E Kishchuk
Keyword(s):  
Nitrogen Availability ◽  
Nutrient Dynamics ◽  
Organic N ◽  
N Availability ◽  
Net N Mineralization ◽  
Mixed Stands ◽  
Clear Cut ◽  
Clear Cutting ◽  
Variable Retention ◽  
Microbial N

Clear-cut harvesting of forests may be associated with increased availability and losses of nitrogen (N), and variable-retention (VR) harvesting has been proposed as an environmentally acceptable alternative to clear-cutting. In boreal forests, however, harvesting has often not led to significant increases in N availability and it is thus important to assess whether variable retention practices are necessary and justifiable in such forests with respect to nutrient dynamics. We compared N availability in clear-cut and VR-harvested stands in the boreal mixedwood forest of northwestern Alberta. We measured soil concentrations of nitrate, ammonium, soluble organic N, and microbial N in uncut, 50% and 20% retention, and clearcuts of deciduous-dominated, coniferous-dominated, and mixed stands 4 years after harvesting. There was little apparent effect of harvesting on N availability in all forest types. Nitrate, ammonium, and microbial N concentrations and net N mineralization and nitrification rates were similar in clearcuts and uncut forests and there was no threshold effect of harvesting on N availability. Soluble organic N concentrations were lower in coniferous and mixed clearcuts than in uncut stands on only one occasion. Clear-cut harvesting in itself does not appear to lead to long-lasting increased N availability and losses in boreal mixedwoods. Adoption of VR harvesting in these ecosystems may not be justified on the grounds of reducing changes in N availability when compared with clear-cutting.

Nitrogen availability in soil and forest floor of contrasting types of boreal mixedwood forests

2006 ◽  
Vol 36 (1) ◽  
pp. 112-122 ◽  
Author(s):  
Lucie Jerabkova ◽  
Cindy E Prescott ◽  
Barbara E Kishchuk
Keyword(s):  
Boreal Forests ◽  
Forest Floor ◽  
Nitrogen Availability ◽  
Mineral Soil ◽  
N Availability ◽  
Net N Mineralization ◽  
Deciduous Species ◽  
Mixed Stands ◽  
Mixedwood Forests ◽  
The North

Boreal mixedwood forests with varying proportions of coniferous and deciduous species are found throughout the North American continent. Maintenance of a deciduous component within boreal forests is currently favoured, as deciduous species are believed to promote faster nutrient turnover and higher nutrient availability. Results of comparisons of deciduous and coniferous forests are, however, inconsistent in supporting this generalization. We compared indices of soil nitrogen (N) availability in the forest floor and mineral soil of deciduous, mixed, and coniferous stands of boreal mixedwood forest in northwestern Alberta. Deciduous stands had higher N availability, reflected by higher pools of NH4-N and inorganic N in the forest floor. Forest floors of deciduous stands also tended to have higher concentrations of microbial N but did not have higher levels of NO3-N or higher rates of net nitrification. Mixed stands showed the highest rates of net N mineralization. Soil N availability was more closely related to litter N content than to litter decomposition rate. The variation among the forest types is likely attributable to vegetation, as topography is fairly uniform, stands do not differ in soil texture, and N-availability indices correlated directly with the proportion of deciduous trees.

scholarly journals Reviews and syntheses: measuring ecosystem nitrogen status – a comparison of proxies

2016 ◽  
Vol 13 (18) ◽  
pp. 5395-5403 ◽  
Author(s):  
Maya Almaraz ◽  
Stephen Porder
Keyword(s):  
N Mineralization ◽  
Nitrogen Availability ◽  
N Availability ◽  
Net N Mineralization ◽  
Tropical Regions ◽  
Net Nitrification ◽  
Kendall’S Τ ◽  
Soil Δ15n ◽  
N Status

Abstract. There are many proxies used to measure nitrogen (N) availability in watersheds, but the degree to which they do (or do not) correlate within a watershed has not been systematically addressed. We surveyed the literature for intact forest or grassland watersheds globally, in which several metrics of nitrogen availability have been measured. Our metrics included the following: foliar δ15N, soil δ15N, net nitrification, net N mineralization, and the ratio of dissolved inorganic to organic nitrogen (DIN : DON) in soil solution and streams. We were particularly interested in whether terrestrial and stream based proxies for N availability were correlated where they were measured in the same place. Not surprisingly, the strongest correlation (Kendall's τ) was between net nitrification and N mineralization (τ  =  0.71, p < 0.0001). Net nitrification and N mineralization were each correlated with foliar and soil δ15N (p < 0.05). Foliar and soil δ15N were more tightly correlated in tropical sites (τ  =  0.68, p < 0.0001), than in temperate sites (τ  =  0.23, p  =  0.02). The only significant correlations between terrestrial- and water-based metrics were those of net nitrification (τ  =  0.48, p  =  0.01) and N mineralization (τ  =  0.69, p  =  0.0001) with stream DIN : DON. The relationship between stream DIN : DON with both net nitrification and N mineralization was significant only in temperate, but not tropical regions. To our surprise, we did not find a significant correlation between soil δ15N and stream DIN : DON, despite the fact that both have been used to infer spatially or temporally integrated N status. Given that both soil δ15N and stream DIN : DON are used to infer long-term N status, their lack of correlation in watersheds merits further investigation.

scholarly journals Nitrogen Availability in Biochar-Amended Soils with Excessive Compost Application

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 444 ◽  
Author(s):  
Chen-Chi Tsai ◽  
Yu-Fang Chang
Keyword(s):  
N Mineralization ◽  
Nitrogen Availability ◽  
Agricultural Soils ◽  
Inorganic Nitrogen ◽  
Clay Content ◽  
N Availability ◽  
Net N Mineralization ◽  
Mineral N ◽  
Mineralization Potential ◽  
The Impact

Adding biochar to excessive compost amendments may affect compost mineralization rate and nitrogen (N) availability. The objective of this 371-day incubation study was to evaluate the effects of four proportions of woody biochar (0%, 0.5%, 1.0%, and 2.0%) from lead tree (Leucaena leucocephala (Lam.) de. Wit) biochar produced at 750 °C through dynamic mineral N and N mineralization rates in three rural soils (one Oxisol and two Inceptisols). In each treatment, 5% poultry–livestock manure compost was added to serve as an excessive application. The results indicated that the biochar decreased available total inorganic nitrogen (TIN) (NO3−-N+NH4+-N) by on average 6%, 9% and 19% for 0.5%, 1.0% and 2.0% treatments, respectively. The soil type strongly influenced the impact of the biochar addition on the soil nitrogen mineralization potential, especially the soil pH and clay content. This study showed that the co-application of biochar and excessive compost benefited the agricultural soils by improving NO3−-N retention in agroecosystems. The application of biochar to these soils to combine it with excessive compost appeared to be an effective method of utilizing these soil amendments, as it diminished the net N mineralization potential and reduced the nitrate loss of the excessive added compost.

Larch litter and nitrogen availability in mixed larch–spruce stands. I. Nutrient withdrawal, redistribution, and leaching loss from larch foliage at senescence

1986 ◽  
Vol 16 (2) ◽  
pp. 321-326 ◽  
Author(s):  
J. C. Carlyle ◽  
D. C. Malcolm
Keyword(s):  
Nitrogen Availability ◽  
Field Measurements ◽  
N Availability ◽  
Mixed Stands ◽  
Available N ◽  
Low Field ◽  
Large N ◽  
Spruce Stands ◽  
And Storage ◽  
N Status

The growth and N status of Sitka spruce on deep peat sites low in available N is improved in the presence of larch. It has been suggested that larch stimulates N mineralization because of high N concentrations in its litter and the large N input resulting from its annual litter fall. However, while larch foliar N concentrations were shown to be high, marked withdrawal and storage in other tree components resulted in a relative and absolute impoverishment of the litter. P and K could be leached from senescing foliage in relatively large amounts, but the potential loss of N was low. Field measurements of throughfall substantiated this finding. Larch seemed extremely conservative in its use of N, suggesting that larch litter does not directly enhance N availability in mixed stands.

Evaluation of three insitu soil nitrogen availability assays

1989 ◽  
Vol 19 (2) ◽  
pp. 185-191 ◽  
Author(s):  
Stephen C. Hart ◽  
Mary K. Firestone
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Nitrogen Availability ◽  
Mineral Soil ◽  
N Availability ◽  
Net N Mineralization ◽  
Old Growth ◽  
The Core ◽  
Young Growth

Three indices of nitrogen (N) availability were compared in the field over a 1-year period in an old-growth and a young-growth mixed-conifer forest. The indices utilized were ion exchange resin (IER) bags, buried bags, and a core-IER method employing intact soil cores enclosed in tubes capped at both ends by IER bags. The results from all three methods indicated that in the surface mineral soil, N availability was higher in the young-growth stand than in the old-growth stand. However, seasonal patterns of N availability were generally not well correlated among the methods (correlation coefficients ranged from 0.32 to 0.62). For a given amount of net N mineralized in buried bags, more N accumulated on IER bags placed in the young-growth stand than in those placed in the old-growth stand. This was the result of greater net nitrification in the young-growth stand coupled with the greater mobility of [Formula: see text] relative to [Formula: see text] in soil. Ten-month estimates of net N mineralization measured by the core-IER and buried-bag methods were similar in the young-growth stand (about 42 mg•kg soil−1), but the core-IER estimate was almost twice that of the buried-bag estimate in the old-growth stand (31.7 and 16.8 mg•kg soil−1, respectively). The different sensitivities of the core-IER and buried-bag methods to changes in soil moisture and leaching probably account for much of the difference in their N availability estimates. Results from the core-IER method did reflect the effects of leaching; however, soil water content within the core did not follow changes in soil water content effectively. Because of the greater labor involved in using the core-IER method, its use may be most efficacious in high-precipitation environments, or when in-field soil incubations must be conducted for extended periods of time.

scholarly journals Dispersed Variable-Retention Harvesting Mitigates N Losses on Harvested Sites in Conjunction With Changes in Soil Microbial Community Structure

2021 ◽  
Vol 3 ◽  
Author(s):  
Carolyn Churchland ◽  
Per Bengtson ◽  
Cindy E. Prescott ◽  
Sue J. Grayston
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Soil Microbial ◽  
Clear Cut ◽  
Clear Cutting ◽  
Variable Retention ◽  
Dispersed Retention ◽  
Variable Retention Harvesting

As an alternative to clear-cutting, variable-retention harvesting is now standard forest management practice on the coast of British Columbia and in temperate forests globally, due to the benefits associated with maintaining mature forest species and forest structural diversity. Although there is some evidence that variable-retention harvesting, particularly single-tree (dispersed) retention will mitigate the impacts of clear-cutting on soil microbial communities and nutrient cycling, findings have been inconsistent. We examined microbial community structure (phospholipid-fatty acid), and nutrient availability (PRSTM probes) in a large (aggregated) retention patch and over three harvesting treatments: dispersed retention, clear-cut and clear-cut edge 2 years after harvest. Unlike previous studies, we did not observe elevated nitrate in the harvested areas, instead ammonium was elevated. Availability of N and other nutrients were surprisingly similar between the dispersed-retention treatment and the retention patch. The microbial community, however, was different in the clear-cut and dispersed-retention treatments, mostly due to significantly lower abundance of fungi combined with an increase in bacteria, specifically Gram-negative bacteria. This was accompanied by lower δ13CPDB value of the Gram-negative PLFA's in these treatments, suggesting the decline in mycorrhizal fungal abundance may have allowed the dominant Gram-negative bacteria to access more of the recently photosynthesized C. This shift in the microbial community composition in the dispersed-retention treatment did not appear to have a major impact on microbial functioning and nutrient availability, indicating that this harvesting practice is more effective at maintaining generic microbial functions/processes. However, as Mn levels were twice as high in the retention patch compared to the harvested treatments, indicating the other “narrow” processes (i.e., those performed by a small number of specialized microorganisms), such as lignin degradation, catalyzed by Mn peroxidase, which concomitantly removes Mn from solution, may be more sensitive to harvesting regimes. The effect of harvesting on such narrow nutrient cycling processes requires further investigation.

scholarly journals Nitrogen Availability from High-nitrogen-containing Organic Fertilizers

2006 ◽  
Vol 16 (1) ◽  
pp. 39-42 ◽  
Author(s):  
T.K. Hartz ◽  
P.R. Johnstone
Keyword(s):  
Blood Meal ◽  
Nitrogen Availability ◽  
Organic Fertilizers ◽  
Organic N ◽  
N Availability ◽  
Vegetable Production ◽  
Feather Meal ◽  
Available N ◽  
Organic Vegetable Production ◽  
Seabird Guano

Limited soil nitrogen (N) availability is a common problem in organic vegetable production that often necessitates in-season fertilization. The rate of net nitrogen mineralization (Nmin) from four organic fertilizers (seabird guano, hydrolyzed fish powder, feather meal, and blood meal) containing between 11.7% and 15.8% N was compared in a laboratory incubation. The fertilizers were mixed with soil from a field under organic management and incubated aerobically at constant moisture at 10, 15, 20, and 25 °C. Nmin was determined on samples extracted after 1, 2, 4, and 8 weeks. Rapid Nmin was observed from all fertilizers at all temperatures; within 2 weeks between 47% and 60% of organic N had been mineralized. Temperature had only modest effects, with 8-week Nmin averaging 56% and 66% across fertilizers at 10 and 25 °C, respectively. Across temperatures, 8-week Nmin averaged 60%, 61%, 62%, and 66% for feather meal, seabird guano, fish powder, and blood meal, respectively. Cost per unit of available N (mineralized N + initial inorganic N) varied widely among fertilizers, with feather meal the least and fish powder the most expensive.

scholarly journals Water and nitrogen processes along a typical water flowpath and streamwater exports from a forested catchment and changes after clear-cutting: a modelling study

2005 ◽  
Vol 9 (6) ◽  
pp. 657-674 ◽  
Author(s):  
A. Laurén ◽  
L. Finér ◽  
H. Koivusalo ◽  
T. Kokkonen ◽  
T. Karvonen ◽  
...  
Keyword(s):  
Buffer Zone ◽  
Organic N ◽  
Ground Vegetation ◽  
Spring Flood ◽  
Total N ◽  
Clear Cut ◽  
Clear Cutting ◽  
N Fluxes ◽  
Before And After ◽  
Eastern Finland

Abstract. A two dimensional model, FEMMA, to describe water and nitrogen (N) fluxes within and from a forested first-order catchment (Kangasvaara in Eastern Finland) was constructed by linking the most significant processes affecting the fluxes of water, ammonium, nitrate and dissolved organic nitrogen along a hillslope from the water divide to the stream. The hillslope represents the average flowpath of water in the catchment and the model was used to estimate the N fluxes for a catchment in eastern Finland before and after clear-cutting. The simulated results were in reasonable agreement with the nitrate, dissolved organic N and dissolved total N measurements from the study catchment and with other results in the literature. According to the simulations, the major sinks of N after clear-cutting were immobilisation by soil microbes, uptake by ground vegetation and sorption to soil. These sinks increased downslope from the clear-cut area, indicating the importance of an uncut buffer zone between the stream and the clear-cut area in reducing N exports. The buffer zone retained 76% of the N flux coming from the clear-cut area. Nitrification was a key process in controlling the N export after clear-cutting and N increases were mainly as nitrate. Most of the annual N export took place during the spring flood, when uptake of N by plants was minimal.

Nitrogen mineralization and nitrification in upland and peatland forest soils in two Canadian Shield catchments

1999 ◽  
Vol 29 (11) ◽  
pp. 1793-1804 ◽  
Author(s):  
Kevin J Devito ◽  
Cherie J Westbrook ◽  
Sherry L Schiff
Keyword(s):  
Forest Soils ◽  
N Mineralization ◽  
Organic N ◽  
Net N Mineralization ◽  
Forest Stands ◽  
Mixed Stands ◽  
N Transformations ◽  
Total N ◽  
Soil C ◽  
Net Mineralization

Net mineralization and nitrification in surface forest soils were measured in upland forest stands and valley peatlands using in situ soil incubations at two headwater catchments of Harp Lake, Ontario from July 1995 to October 1996. No difference in either net N mineralization or nitrification was observed between the two adjacent catchments despite differences in catchment N export. Annual rates of net N mineralization in surface 10 cm were higher in forest soils of the deciduous (11.5 ± 3.1 g/m2; mean ± SE) and conifer-mixed (conifer-hardwoods) (13.9 ± 2.3 g/m2) stands than in peatland soils (1.6 ± 0.6 g/m2). Mean annual nitrification rates were higher in deciduous soils (6.6 ± 0.7 g N/m2) than in mixed stands (1.9 ± 0.6 g N/m2) and peatland soils (0.1 ± 0.2 g N/m2). Annual net N mineralization and nitrification were correlated with variations in soil C and N content and moisture associated with different forest stands. Frequent winter incubations indicate that net mineralization and nitrification under snow cover in upland surface soils can contribute as much as 49 and 23% of the annual net production, respectively. The importance of forest vegetation patterns, winter N transformations, and dissolved organic N pools to total N and NO3- cycling and leaching in these catchments is discussed.

AVAILABILITY OF NITROGEN FROM THREE MANURES TO CORN IN THE FIELD

1986 ◽  
Vol 66 (4) ◽  
pp. 713-720 ◽  
Author(s):  
E. G. BEAUCHAMP
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Cattle Manure ◽  
N Immobilization ◽  
Organic N ◽  
Yield Response ◽  
N Availability ◽  
Net N Mineralization ◽  
Yield Data ◽  
Total N

Three manures were compared with urea as sources of nitrogen for corn (Zea mays L.) on a different field site in each of 3 yr. The manures and their average [Formula: see text]–N:total N ratios were as follows: liquid poultry manure (LPM), 0.89; liquid dairy cattle manure (LCM), 0.53; and solid beef cattle manure (SBM), 0.09. The manures were applied at rates of 100, 200 and 300 kg total N ha−1. An additional LCM treatment of 600 kg total N ha−1 was also included. For comparison with the manures as N sources, urea was applied at rates of 50, 100 and 150 kg N ha−1. The yield response data were examined on the basis of a previously suggested model which predicted that all of the [Formula: see text]–N and part (e.g., 10–20%) of the organic N in manures are available for crop growth in the field. Regression analyses of paired yield data sets of urea and LCM or urea and LPM indicated that only 75–80% of the [Formula: see text]–N fraction applied in these manures was equivalent to urea-N. Thus, it was concluded that the model did not take into account net N immobilization and possibly N losses through denitrification following application. It was concluded also that N release from the organic N fraction of SBM differed substantially from that for the other manures. This conclusion was supported by greenhouse data which indicated that net N immobilization occurred for the first crop shortly after SBM was applied but this was followed by net N mineralization for a second crop as manure decomposition continued. Soil NO3− concentrations in mid-June generally increased with the urea, LPM and LCM sources of N at the higher rates of application in the field. Lower soil NO3− concentrations with SBM reflected the lower availability of N. Key words: Corn, manure N availability, Zea mays L.

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