COMPARISON OF NITROGEN MINERALIZATION IN FOREST FLOOR MATERIALS USING AEROBIC AND ANAEROBIC INCUBATION AND BIOASSAY TECHNIQUES

1990 ◽  
Vol 70 (1) ◽  
pp. 73-81 ◽  
Author(s):  
J. W. FYLES ◽  
I. H. FYLES ◽  
M. C. FELLER
Keyword(s):  
Nitrogen Mineralization ◽  
N Mineralization ◽  
Forest Floor ◽  
N Uptake ◽  
Morphological Characteristics ◽  
Site Quality ◽  
Order Kinetic ◽  
Forest Floors ◽  
Highly Correlated ◽  
Aerobic And Anaerobic

Nitrogen mineralization in five forest floors of differing morphological characteristics was compared using a greenhouse plant bioassay and laboratory aerobic and anaerobic incubations. Forest floors dominated by F materials mineralized more N and had higher k values than those dominated by H. Plant N uptake in the bioassay was highly correlated with N mineralized during the laboratory incubations across all forest floors but was 50–80% lower than predictions based on first-order kinetic parameters derived from the aerobic incubation. The relationship between bioassay plant uptake and predicted N mineralization differed among forest floors, indicating that the effect of plants on dynamics of the mineralizable N pool differs among organic matter types. Differences in N mineralization characteristics between forest floor materials suggest that forest floor morphology may provide a basis for assessing site quality. Key words: Nitrogen, anaerobic mineralization, aerobic mineralization, bioassay, forest floor

Nitrogen availability in forest floors of three tree species on the same site: the role of litter quality

2000 ◽  
Vol 30 (11) ◽  
pp. 1698-1706 ◽  
Author(s):  
K D Thomas ◽  
C E Prescott
Keyword(s):  
Nitrogen Mineralization ◽  
Tree Species ◽  
N Mineralization ◽  
Forest Floor ◽  
Lodgepole Pine ◽  
Douglas Fir ◽  
Net N Mineralization ◽  
N Concentration ◽  
Paper Birch ◽  
Forest Floors

Forest floor samples from a 25-year-old plantation of three tree species (Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), and paper birch (Betula papyrifera Marsh.)) growing on the same site were incubated (aerobically) in the laboratory for 29 days. Rates of N mineralization in the forest floors of Douglas-fir (165.1 µg/g) was significantly greater than either birch (72.9 µg/g) or lodgepole pine (51.2 µg/g). Douglas-fir forest floors also had the highest N concentration, lowest C/N ratio, and highest NH4-N concentrations, followed by paper birch and lodgepole pine. Douglas-fir forest floors also mineralized more N per unit of either N or C than the other species. There were no differences in rates of CO2-C mineralization in forest floors among the three species. Nitrogen mineralization rates were positively correlated with the N concentration of the forest floor (r2 = 0.81) and also with the C/N and NH4-N concentration of the forest floor. Nitrogen concentration, C/N, and lignin/N of foliar litter were poor predictors of N mineralization rates resulting from Douglas-fir litter having the lowest N concentrations in litter but the highest rates of net N mineralization in the forest floor. Nitrogen mineralization in the forest floor was negatively correlated (r2 = 0.67) with the lignin concentration in foliar litter. Douglas-fir litter had low lignin concentrations, which may allow more of the mineralized N to remain in inorganic forms rather than being bound in humus. Our results suggest that a component of Douglas-fir might improve N availability in coniferous forest floors.

The use of laboratory measurements to predict nitrogen mineralization and nitrification in Pinus radiata plantations after harvesting

1998 ◽  
Vol 28 (8) ◽  
pp. 1213-1221 ◽  
Author(s):  
J Clive Carlyle ◽  
EK Sadanandan Nambiar ◽  
Mark W Bligh
Keyword(s):  
Nitrogen Mineralization ◽  
Pinus Radiata ◽  
N Mineralization ◽  
Forest Floor ◽  
Mineral Soil ◽  
Net N Mineralization ◽  
Laboratory Measurements ◽  
Aerobic Incubation ◽  
Highly Correlated ◽  
Sequential Coring

We tested whether laboratory estimates of net N mineralization and nitrification (subsequently termed N mineralization and nitrification) could be used to predict these processes in the field after harvesting nine Pinus radiata D. Don. plantations. Laboratory rates of N mineralization and nitrification were measured by aerobic incubation (20°C) of intact cores. Annual rates of these processes in the field were measured using a sequential coring procedure. Rates of N mineralization in the laboratory were 1.1-6.6 and 0.019-0.525mg·kg-1·day-1 for forest floor and mineral soil, respectively (nitrification accounted for 6-71 and 8-93% of N mineralization). Annual N mineralization by forest floor in the field was 5.2-23.9kg·ha-1·year-1and was not correlated with N mineralized in the laboratory. Annual N mineralization in mineral soil in the field was 16-74kg·ha-1·year-1and was highly correlated (r2 = 0.97) with N mineralized in the laboratory. Annual nitrification in forest floor in the field ranged from 3 to 45% of annual N mineralization, and in mineral soil from 4 to 27%, both were correlated with relative nitrification measured in the laboratory.

Bioassay of forest floor nitrogen supply for plant growth

1986 ◽  
Vol 16 (6) ◽  
pp. 1320-1326 ◽  
Author(s):  
K. Van Cleve ◽  
O. W. Heal ◽  
D. Roberts
Keyword(s):  
Forest Floor ◽  
Black Spruce ◽  
Nitrogen Concentration ◽  
N Uptake ◽  
Mineral Soil ◽  
Forest Types ◽  
N Supply ◽  
Paper Birch ◽  
Forest Floors ◽  
P Supply

Using a bioassay approach, this paper considers the nitrogen-supplying power of forest floors from examples of the major forest types in interior Alaska. Yield and net N uptake by paper birch seedlings grown in standardized mixtures of quartz sand and forest floor organic matter, and separate incubation estimates of N mineralization and nitrification for the forest floors, were employed to evaluate potential N supply. Black spruce and floodplain white spruce forest floors supplied only one-fifth the amount of N taken up by seedlings growing in other forest floors. Incubation estimates showed these forest floors yielded 4 and 15 times less extractable N, respectively, than the more fertile birch forest floors. In comparison with earlier estimates of P supply from these same forest floors, the upland types showed greater deficiency of N whereas floodplain types showed greater deficiency of P in control of seedling yield. The latter condition is attributed to the highly calcareous nature of the floodplain mineral soil, the consequent potential for P fixation, and hence greater potential deficiency of the element compared with N in mineralizing forest floors. Nitrogen concentration of the forest floors was the best predictor of bioassay response.

Nutrient concentrations and nitrogen mineralization in forest floors of single species conifer plantations in coastal British Columbia

2000 ◽  
Vol 30 (9) ◽  
pp. 1341-1352 ◽  
Author(s):  
C E Prescott ◽  
L Vesterdal ◽  
J Pratt ◽  
K H Venner ◽  
L M de Montigny ◽  
...  
Keyword(s):  
Nitrogen Mineralization ◽  
Tree Species ◽  
N Mineralization ◽  
Single Species ◽  
Douglas Fir ◽  
Picea Sitchensis ◽  
Slope Position ◽  
Nutrient Concentrations ◽  
Net N Mineralization ◽  
Forest Floors

We examined the extent to which nutrient concentrations and C and N mineralization rates in forests floors under different tree species are predictable from the chemistry of foliar litter and its rate of decomposition. We studied replicated single species plantations of western redcedar (Thuja plicata Donn ex D. Don), western hemlock (Tsuga heterophylla (Raf.) Sarg.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and Sitka spruce (Picea sitchensis (Bong.) Carr.) at four locations. Nutrient concentrations in forest floors correlated poorly with litter nutrient concentrations; the only significant relationships were for Ca and K. Nitrogen mineralization correlated weakly with forest floor C/N ratio, and differed more among sites than among species. None of the litter chemistry parameters were related to net N mineralization rates. Decomposition was fastest in hemlock litter, intermediate in Douglas-fir litter and lowest in cedar litter. Litter also decomposed more rapidly on hemlock forest floors than on cedar forest floors. Rates of N mineralization in the forest floors were not related to rates of decomposition of foliar litter. Differences among sites in N mineralization rates were related to the understory vegetation composition, particularly the amount of the ericaceous shrub salal, which in turn was related to slope position. These site factors appeared to override the effect of tree species on rates of N mineralization.

Nitrogen mineralization characteristics of forest floor organic matter on slash-burned sites in coastal British Columbia

1991 ◽  
Vol 21 (2) ◽  
pp. 235-241
Author(s):  
J. W. Fyles ◽  
I. H. Fyles ◽  
M. C. Feller
Keyword(s):  
Organic Matter ◽  
Nitrogen Mineralization ◽  
N Mineralization ◽  
Forest Floor ◽  
Soil Survey ◽  
Total N ◽  
Potentially Mineralizable N ◽  
N Fertility ◽  
Low K ◽  
Floor Material

Nitrogen mineralization characteristics of the dominant types of organic matter in the forest floor of slash-burned sites were measured using a 26-week aerobic incubation. Six classes of forest floor material were distinguished on the basis of morphology and N mineralization characteristics. Fermentation layer materials, matted together with fungal hyphae, had a high content of total and potentially mineralizable N (N0) (7804 and 2816 μg/g, respectively) and mineralized the most N during incubation (1605 μg/g). Decayed wood had the lowest level of total N (1816 μg/g) and N0 (195 μg/g) and mineralized the least N (266 μg/g) despite a high inherent mineralization rate (k) (0.16). Humified materials (Hd and Hr) occupied a midrange, with the exception of those from thin residual horizons, which had high N0 values (2246–6009 μg/g) and low k-values (0.005–0.012). The significant differences in N mineralization among organic materials that are morphologically or ecologically distinct in the field suggest that it may be possible to assess site N fertility using intensive forest floor and soil survey data and information on the N characteristics of dominant horizon types.

Nitrogen mineralization and nitrification in successional ecosystems on the Tanana River floodplain, interior Alaska

1993 ◽  
Vol 23 (5) ◽  
pp. 970-978 ◽  
Author(s):  
K. Van Cleve ◽  
J. Yarie ◽  
R. Erickson ◽  
C.T. Dyrness
Keyword(s):  
Soil Temperature ◽  
Nitrogen Mineralization ◽  
N Mineralization ◽  
Vegetation Type ◽  
Mineral Soil ◽  
Net N Mineralization ◽  
Litter Layer ◽  
River Floodplain ◽  
Interior Alaska ◽  
Forest Floors

Nitrogen (N) mineralization and nitrification were compared among ecosystems representing a primary successional sequence on the Tanana River floodplain of interior Alaska. These processes displayed marked seasonality, were closely related to substrate chemistry, and reflected the impact of vegetation clearing. The highest rates of N mineralization were encountered in the June to July incubation periods, and rates generally declined during the remainder of the summer. The early season period (June to July) was the interval of most favorable litter and mineral soil temperature and most available energy supply for microbial mineralization of detrital materials. Minimal rates were encountered during the winter. Litter layer N mineralization rates were highest in the early-successional poplar–alder (Populusbalsamifera–Alnustenuifolia (Nutt.) stage and declined with advancing succession in poplar (Populusbalsamifera) and mature white spruce (Piceaglauca) (Moench) Voss) stands. The poplar–alder stage displayed the highest rate of nitrification. Nitrate constituted 98% of the mineralized N in early-successional poplar–alder forest floors but fell to 4 and 0% in poplar and white spruce forest floors, respectively. Nitrogen mineralization was closely related to significant increases in the lignin/N ratio across the sequence of vegetation types. The rate of surface mineral soil net N mineralization increased with succession in response to higher soil organic matter content. The range of average total seasonal net N mineralization (260–1600 mg N•m−2) for litter layer plus mineral soil among successional stages in this study was generally lower than the 1200–8400 mg N•m−2 reported by investigators for other studies in temperate latitudes. Vegetation clearing increased the magnitude of temporal fluxes as well as total annual mineral N production. The most consistent increases were encountered in the poplar–alder vegetation type. The average seasonal total net N mineralization for forest floor plus mineral soil in this vegetation type increased from 1500 to 3264 mg N•m−2 as a result of clearing. Soil temperature declined with advancing succession and generally increased as a consequence of clearing. However, these changes were not as closely correlated with N mineralization as were the changes in substrate chemistry encountered across this successional sequence.

Forest floor characteristics and soil nitrogen availability on slash-burned sites in coastal British Columbia

1991 ◽  
Vol 21 (10) ◽  
pp. 1516-1522 ◽  
Author(s):  
J. W. Fyles ◽  
I. H. Fyles ◽  
W. J. Beese ◽  
M. C. Feller
Keyword(s):  
Organic Matter ◽  
N Mineralization ◽  
Forest Floor ◽  
Nitrogen Availability ◽  
Model Parameters ◽  
N Availability ◽  
Order Kinetic ◽  
Fire Weather Index ◽  
First Order ◽  
Morphological Criteria

Organic forest floor materials were surveyed on spring and fall slash-burned sites in the Sproat Lake region of Vancouver Island 2 years after burning. Dominant organic matter types, distinguished according to morphological criteria, were sampled and incubated in the laboratory for 26 weeks with periodic leaching and measurement of mineral N. Mineralization data closely fit a first-order kinetic model. Field mineralization, estimated using mass of each organic matter type in the field and first-order model parameters corrected for local temperature, ranged from 2 to 6 g N•m−2•year−1, depending on burn severity, suggesting that slash burning did not reduce N availability below levels required to support early plantation growth, except in situations of severe burns on coarse-textured soils. Differential consumption of forest floor organic matter types increased spatial variability in N mineralization and resulted, at the most severely burned site, in 50% of mineralizable N being derived from materials covering only 5% of the site. Significant correlation between N mineralization and codes and indices of the Canadian Forest Fire Weather Index System indicated that predictions of slash-burn impacts on site fertility may be made from weather conditions prior to and during burning.

Nitrogen mineralization and decomposition in forest floors in adjacent plantations of western red cedar, western hemlock, and Douglas-fir

1994 ◽  
Vol 24 (12) ◽  
pp. 2424-2431 ◽  
Author(s):  
C.E. Prescott ◽  
C.M. Preston
Keyword(s):  
Mass Loss ◽  
N Mineralization ◽  
Forest Floor ◽  
Douglas Fir ◽  
Western Hemlock ◽  
N Availability ◽  
Net N Mineralization ◽  
Red Cedar ◽  
Western Red Cedar ◽  
Forest Floors

To determine if western red cedar (Thujaplicata Donn) litter contributes to low N availability in cedar–hemlock forests, we measured concentrations of N and rates of net N mineralization in forest floors from single-species plantations of cedar, western hemlock (Tsugaheterophylla (Raf.) Sarg.), and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) on the same site in coastal British Columbia. Concentrations of total and extractable N and rates of net N mineralization during laboratory incubations were lowest in the cedar forest floor and highest in Douglas-fir. Less C was mineralized in the cedar forest floor during incubation, and the amount of N mineralized per unit C was least in cedar. Rates of mass loss of foliar litter of the three species were similar during the first 50 weeks of a 70-week laboratory incubation, but cedar lost mass more quickly during the final 20 weeks. Rates of net N mineralization in the forest floors were significantly correlated with the initial percent N, C/N, % Klason lignin, and lignin/N of foliar litter. Foliar litter of cedar had lower concentrations of N and greater proportions of alkyl C (based on 13C NMR spectroscopy) than Douglas-fir litter. These characteristics of cedar litter may contribute to low N availability in cedar–hemlock forest floors. Concentrations of alkyl C (waxes and cutin) may be better than lignin for predicting rates of mass loss and N mineralization from litter.

Are forest floors in mid-rotation stands of loblolly pine (Pinus taeda) a sink for nitrogen and phosphorus?

2001 ◽  
Vol 31 (7) ◽  
pp. 1164-1174 ◽  
Author(s):  
Kathryn B Piatek ◽  
H Lee Allen
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
N Mineralization ◽  
Forest Floor ◽  
Nutrient Dynamics ◽  
Net N Mineralization ◽  
Litter Bags ◽  
Forest Floors ◽  
Fresh Litter

We examined decomposition and nutrient dynamics in fresh litter and net N mineralization in old litter to determine (i) if forest floor is a source of available nutrients in mid-rotation loblolly pine (Pinus taeda L.) stands and (ii) the effect of site preparation and vegetation control on forest floor nutrient dynamics. Four types of fresh litter were decomposed in situ in mesh bags: two containing only pine (differing by history of stand management) and two pine–hardwood mixes (ratios 1:5 and 5:1). Litter bags were recovered every May and October for 26 months. Litter type, in particular the presence and amount of leaves, affected decomposition and nutrient dynamics in fresh litter. After 26 months, all fresh litters lost 55% of mass; decay rate constants were 0.43 (needles) to 0.60 year–1 (leaves). Pine (1) and pine (2) and needles in mix 1:5 immobilized N. Almost all fresh litters also immobilized P. After 26 months of decay, N and P pools suggested an accumulation in the needles of 0.7–2.7 kg N·ha–1 and 0.2–0.5 kg P·ha–1 and mineralization of 1.1–3.7 kg N·ha–1 in mix 5:1 needles and mix 1:5 leaves. All fresh litters mineralized K, Ca, and Mg. Old litter was incubated in situ in capped polyvinyl chloride containers from May to November. Monthly rates of net N mineralization in old litter were determined in KCl extracts of NH4+ and NO3–. Net N mineralization in old litter was 0.75–1.5 kg N·ha–1 per 6 months and was attributed to mineralization in mineral soil. We conclude that forest floors in these stands are not a source of available N or P. Instead, forest floors appear to be sinks for N and probably P.

Nutrient management in a Pinusradiata plantation after thinning: the effect of thinning and residues on nutrient distribution, mineral nitrogen fluxes, and extractable phosphorus

1995 ◽  
Vol 25 (8) ◽  
pp. 1278-1291 ◽  
Author(s):  
J. Clive Carlyle
Keyword(s):  
Moisture Content ◽  
N Mineralization ◽  
Forest Floor ◽  
N Uptake ◽  
Mineral Soil ◽  
Basal Area ◽  
Nutrient Distribution ◽  
Extractable P ◽  
Soil Temperatures ◽  
Residue Retention

The effects of thinning and residues on nutrient distribution, N fluxes, and extractable P were studied for 3 years after the first thinning of a 10-year-old Pinusradiata D. Don plantation. Treatments were (i) unthinned, (ii) thinned to 52% of basal area with all residues removed (zero residue; ZR), (iii) thinned with all residues retained and spread uniformly (normal residue; NR), and (iv) thinned with all residues retained plus the addition of those removed from the ZR treatment, approximately doubling the amount of residue in treatment NR (high residue; HR). The total nutrient contents of trees (above ground), residues, forest floor, and the top 0.30 m of mineral soil were 1206 kg N•ha−1, 126 kg P•ha−1, 828 kg K•ha−1, and 1272 kg Ca•ha−1 after thinning. Residues contained 11, 10, 10, and 7% of site N, P, K, and Ca, respectively. Thinning without residue retention (unthinned cf. ZR) elevated mean monthly maximum soil temperatures at a depth of 50 mm by up to 5.3 °C in summer and 1 °C in winter. Thinning had no effect on forest floor or mineral soil (0–0.30 m) moisture content. In the unthinned treatment an average of 25 kg N•ha−1•year−1 was mineralized, all of which was taken up by the trees, and there was no leaching. Thinning caused a 10% increase in rates of N mineralization and uptake and a small transient increase in soil mineral N concentrations, but had no effect on leaching. Maintenance of prethinning levels of N uptake by the remaining trees (after a 48% reduction in basal area) suggests that uptake per tree was approximately doubled. Maintenance of N uptake after thinning was consistent with maintenance of basal area growth (m2•ha−1) and an increase in foliar N concentrations. Thinning had no effect on extractable P in the forest floor or mineral soil. The retention of residues (NR and HR) decreased mean monthly maximum and elevated mean monthly minimum soil temperatures relative to the ZR treatment, and the effect increased with the amount of residue. Forest floor moisture content increased with the amount of residue, but residue retention had no effect on mineral soil moisture. Rates of mineralization were higher in the presence of residue and annual averages were 28, 33, and 42 kg N•ha−1•year−1 for ZR, NR, and HR treatments, respectively. Despite increased N mineralization in the presence of residue there was no leaching and all the additional N was taken up by the trees. Basal area increment increased in the presence of residue (P = 0.235) and was 10.7 (ZR), 11.1 (NR), and 11.8 (HR) m2•ha−1 over 4 years of measurement.

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