Nitrogen mineralization in forest soil profiles from central Alberta

1987 ◽  
Vol 17 (3) ◽  
pp. 242-249 ◽  
Author(s):  
J. W. Fyles ◽  
W. B. McGill
Keyword(s):  
Nitrogen Mineralization ◽  
Soil Profiles ◽  
Forest Site ◽  
N Availability ◽  
Total N ◽  
Short And Long Term ◽  
Potentially Mineralizable N ◽  
N Fertility ◽  
Time Frames

The nitrogen mineralization characteristics of soils from stands dominated by jack pine (Pinusbanksiana Lamb.) and white spruce (Piceaglauca (Moench) Voss) were examined using a 37-week incubation with periodic leaching to allow measurement of mineralized N. Soils were compared on the basis of total N, N mineralized during the incubation, potentially mineralizable N, mineralization rate constant, and nitrification potential. Nitrogen characteristics of LFH horizons primarily reflected the age and species composition of the existing vegetation while those of A horizons appeared to relate to conditions in previous as well as present stands. Characteristics of B horizons were independent of vegetation implying control by long-term accumulation and transformation of N within the soil. The N fertility of a forest site therefore represents the integration of processes acting within different time frames and an understanding of the relative contributions of short- and long-term processes in the control of N availability is required for efficient fertility management.

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.

scholarly journals Nitrogen availability determines the long-term impact of land use change on soil carbon stocks in grasslands of southern Ghana

SOIL ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 523-539
Author(s):  
John Kormla Nyameasem ◽  
Thorsten Reinsch ◽  
Friedhelm Taube ◽  
Charles Yaw Fosu Domozoro ◽  
Esther Marfo-Ahenkora ◽  
...  
Keyword(s):  
Land Use ◽  
N Availability ◽  
Plant Metabolites ◽  
Total N ◽  
Low Input ◽  
Native Grassland ◽  
Livestock Systems ◽  
Southern Ghana ◽  
Soc Stocks

Abstract. Enhancing the capacity of agricultural soils to resist soil degradation and to mitigate climate change requires long-term assessments of land use systems. Such long-term evaluations, particularly regarding low-input livestock systems, are limited. In the absence of suitable long-term experiments, this study assessed the outcome of C inputs and outputs across an array of plant functional groups in arable and permanent systems of a tropical savannah after more than 50 years of consistent land use. Soil samples were taken (0–30 cm depth) from arable crop fields, grazed–seeded grassland, cut–use permanent crops and native grassland. Soil organic carbon (SOC) stocks ranged from 17 to 64 Mg SOC ha−1 (mean ± sd = 32.9 ± 10.2 Mg ha−1). SOC stocks were lower for grazed–seeded grassland relative to cut–use grass, legume trees and shrubs. Accordingly, while the conversion of the native grassland to grazed pastures caused an estimated loss of 44 % of SOC over the period, the conversion to woody legumes resulted in slight (5 %), incremental gains. Within sown systems, nitrogen (N) availability seemed to be the most critical factor in determining the fate of the SOC stocks, with the soil N concentration and SOC being highly correlated (r – 0.86; p < 0.001). In total N, P and K were significant predictors of SOC density in the soils. Moreover, secondary plant metabolites in legumes, namely tannins, were identified as having an impact on SOC. The results from this study provide the theoretical basis for testing the hypothesis that improved soil fertility management and the use of tannin-rich plants have the potential to promote long-term SOC storage in the savannah ecological region. Our study also shows the potential of legume tree/shrub forage species as an environmentally sustainable land use option to mitigate agricultural CO2 emissions from low-input livestock systems in the grasslands of southern Ghana.

Nitrogen and carbon cycling in a New Zealand pumice soil under a manuka (Leptospermum scoparium) and kanuka (Kunzea ericoides) shrubland

Soil Research ◽  
2009 ◽  
Vol 47 (7) ◽  
pp. 725 ◽  
Author(s):  
D. J. Ross ◽  
N. A. Scott ◽  
S. M. Lambie ◽  
C. M. Trotter ◽  
N. J. Rodda ◽  
...  
Keyword(s):  
New Zealand ◽  
Mineral Soil ◽  
N Cycling ◽  
Stand Age ◽  
Forest Site ◽  
N Availability ◽  
Volcanic Soils ◽  
Total N ◽  
Kunzea Ericoides ◽  
Leptospermum Scoparium

Shrubland communities dominated by manuka (Leptospermum scoparium J. Forst. and G. Forst.) and kanuka (Kunzea ericoides var. ericoides ((A. Rich) J. Thompson) are widespread throughout New Zealand. They frequently colonise disturbed land surfaces and are important for erosion mitigation, and also for their capacity to act as a carbon (C) sink. We here investigate C and nitrogen (N) cycling in 3 stands (~26–56 years old) that had established on a repeatedly burned forest site on a Podzolic Orthic Pumice soil in the Turangi area, central North Island. For comparison, limited measurements of N cycling were also made at other manuka–kanuka sites on non-volcanic soils. Leaf N concentrations at the Turangi site were 11.8–13.9 g/kg, and lower than those at many of the other manuka–kanuka stands. Total annual litterfall and N content increased with stand age, as did total N concentrations in FH material and mineral soil (0–100 mm depth). Total C concentrations in mineral soil did not, however, differ significantly in the 3 stands. Levels of soil microbial C and N, rates of carbon dioxide production, and metabolic coefficients (qCO2 values) suggest C cycling could be fairly rapid at this site. In contrast, rates of net mineral-N and nitrate-N production were low to very low compared with those in similar pumice soils under angiosperm–conifer forests, and in the non-volcanic soils under other manuka–kanuka stands. Low N availability and tight N cycling at the Turangi site are thereby strongly suggested. No definitive explanation for the atypically low N availability at this site is apparent, although the possible effects of previous forest burnings may have been a contributing factor. The continued growth of these shrubs, nevertheless, shows they can compete successfully for the N that does become available through gross N mineralisation in the Turangi ecosystem.

Repeatability of methane emission measurements in Australian beef cattle

2016 ◽  
Vol 56 (3) ◽  
pp. 213 ◽  
Author(s):  
K. A. Donoghue ◽  
T. Bird-Gardiner ◽  
P. F. Arthur ◽  
R. M. Herd ◽  
R. S. Hegarty
Keyword(s):  
Methane Production ◽  
Life Time ◽  
Time Frame ◽  
Phenotypic Correlations ◽  
Methane Production Rate ◽  
Short And Long Term ◽  
Time Periods ◽  
Time Frames ◽  
Methane Measurement

Records on 175 young Angus heifer and bull progeny from 46 sires, measured for methane production in respiration chambers, were used to evaluate the repeatability of methane measurement over short- and long-term periods. The traits assessed were dry matter intake (DMI), methane production rate (MPR), methane yield (MPR per unit DMI), and four residual methane (RMP) traits. The RMP traits were computed as actual MPR minus expected MPR, where the expected MPR for the first three RMP traits were calculated from three different published and widely used equations. The expected MPR for the fourth was computed by regressing MPR on DMI, using the data from the study. Animals underwent an initial (first) methane measurement test for 48 h, and one repeat methane measurement test up to 450 days after the first test. Repeat tests were classified into four different time periods: tested across consecutive days; re-tested within 60 days of first test; re-tested 61–120 days after first test; and re-tested 121–450 days after first test. Repeatabilities were calculated for all traits across all time periods, and phenotypic correlations for the same trait measured over time were obtained from bivariate analyses. Methane traits from tests conducted over consecutive days were highly repeatable (0.75–0.94) and highly phenotypically correlated (0.85–0.95). Repeatabilities from tests conducted within 60 days of the first test were moderate to high (0.59–0.91), whereas phenotypic correlations were, in general, moderate (0.30–0.44), with the exception of MPR (0.78). Results for both longer-term time periods (61–120 days and 121–450 days after the first test) were very similar, with low estimates of repeatabilities (0.16–0.27) and phenotypic correlations (0.12–0.27). Correlations between sire progeny means from the first and repeat methane test were moderate (0.46–0.77) for all traits except RMPR (0.19). Results from this study indicate that methane traits from tests conducted either on consecutive days or within a short-term time frame afterward (~60 days) are highly repeatable and highly phenotypically correlated. However, methane tests conducted over longer-term time frames are substantially, but consistently, less repeatable and are lowly phenotypically correlated, which indicates that multiple measures may be required to accurately record methane traits over the life time of an animal.

scholarly journals Altered Nitrogen Availability in Pea–Barley Sole- and Intercrops Changes Dominance of Two Nitrophilic Weed Species

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 679
Author(s):  
Ortrud Jäck ◽  
James Ajal ◽  
Martin Weih
Keyword(s):  
Weed Management ◽  
Nitrogen Availability ◽  
Chenopodium Album ◽  
N Fixation ◽  
N Availability ◽  
Weed Species ◽  
15N Isotope ◽  
Total N ◽  
N Sources

Effective and sustainable weed management in agricultural fields is a prerequisite for increasing crop yield without negatively impacting the environment. The aim of this study was to explore how varying nitrogen (N) availability in cropping arrangements of pea (Pisum sativum) and barley (Hordeum vulgare) grown as sole crops and intercrops at different fertilization levels and considering different N sources (soil mineralization, N fixation, N fertilizer) affects the response of weed species with differential N responsiveness. Crop and weed biomass were sampled at flowering and maturity. The total N content and 15N isotope signatures were analyzed to differentiate between N sources and to estimate the amount of N available to weeds. The highly N-responsive weed (Chenopodium album) accumulated more N and biomass than the weed with reduced N responsiveness (Galeopsis spp.). Fertilizer supply favored Chenopodium album, but not the crops. Altered soil N availability caused a shift in the dominance of the nitrophilic weed species towards the highly N-responsive species. This shift in dominance could affect the long-term weed community composition and thus have implications for sustainable weed management.

Quantification of the Effect of Fumigation on Short- and Long-Term Nitrogen Mineralization and Nitrification in Different Soils

2004 ◽  
Vol 33 (5) ◽  
pp. 1647-1652 ◽  
Author(s):  
Stefaan De Neve ◽  
Gabor Csitári ◽  
Joost Salomez ◽  
Georges Hofman
Keyword(s):  
Nitrogen Mineralization ◽  
Short And Long Term ◽  
Different Soils

scholarly journals Effect of Large Inputs of Manure and Fertilizer on Nitrogen Mineralization in the Newly Built Solar Greenhouse Soils

HortScience ◽  
2019 ◽  
Vol 54 (9) ◽  
pp. 1600-1604
Author(s):  
Shichao Wang ◽  
Zhujun Chen ◽  
Jun Man ◽  
Jianbin Zhou
Keyword(s):  
N Mineralization ◽  
Soil Layer ◽  
Total N ◽  
Soil Layers ◽  
Application Rates ◽  
Age Regression ◽  
Solar Greenhouse ◽  
Greenhouse Soils ◽  
Potentially Mineralizable N

In China, greenhouse soils often receive large rates of different manures and have a high content of soil organic matter (SOM). Understanding changes in nitrogen (N) mineralization in soils of newly built greenhouses after their construction is important for managing N. Soil samples were obtained from solar greenhouses of different ages (0, 1, 2, and 3 years) located in the south edge of the Loess Plateau, China, at 0- to 20- and 20- to 40-cm depth. N mineralization in the soils was measured with the Stanford and Smith long-term aerobic incubation method over 30 weeks. SOM, total N, and the mineralized N in the 0- to 20-cm and 20- to 40-cm soil layers were significantly increased in the older greenhouses. The cumulative mineralized N in the 0- to 20-cm soil layer in different cultivation years was increased in each year since the greenhouses were established. For the greenhouses with the same age, the cumulative mineralized N in the 0- to 20-cm soil layer was greater than that in the 20- to 40-cm layer. The potentially mineralizable N (N0) both in the 0- to 20-cm and the 20- to 40-cm soil layers increased with the greenhouses’ age. Regression analysis indicated that when SOM increased 1 g·kg−1, N0 in the 0- to 20-cm and 20- to 40-cm depth increased 22.6 and 8.4 mg·kg−1, respectively. Therefore, as the N supply in soil increases with the age of the solar greenhouse, we suggest that the application rates of manure and synthetic fertilizer be reduced.

Time for Absenteeism: A 20-Year Review of Origins, Offshoots, and Outcomes

1998 ◽  
Vol 24 (3) ◽  
pp. 305-350 ◽  
Author(s):  
David A. Harrison ◽  
Joseph J. Martocchio
Keyword(s):  
Poor Performance ◽  
Job Attitudes ◽  
Social Environments ◽  
Long Term Effects ◽  
Short Term ◽  
Research Attention ◽  
Explicit Consideration ◽  
Short And Long Term ◽  
Time Frames

We use a time-based system to help organize, summarize, and analyze research on employee absenteeism published in the last 20 years (1977-1996). Although what is known about some mid-term (4-12 month) origins of absence-taking has been greatly clarified and expanded, less is known about long-term (> 12 months) and short-term (I day-3 months) origins, or about how causes in different time frames relate to each other. Poor performance and “neglectful” behaviors serve as reliable offshoots of absenteeism. The long- and short-term etiology of the latter behaviors is unclear, but their shared variance in the mid-term reflects negative job attitudes. Outcomes of absenteeism have received much less research attention. Although mid-term consequences such as reduced performance, turnover, and organizational expense are well-established, little is known about short- and long-term effects of absence-taking on individuals and their social environments. We conclude with suggestions for more explicit consideration of time frames, causal lags, and aggregation periods in the next decades of absenteeism research.

scholarly journals A review of methods to assess the economic impact of distributed medical education (DME) in Canada

2018 ◽  
Vol 9 (1) ◽  
pp. e87-99
Author(s):  
Kim Lemky ◽  
Pierre Gagne ◽  
Jill Konkin ◽  
Karl Stobbe ◽  
Gervan Fearon ◽  
...  
Keyword(s):  
Medical Education ◽  
Economic Impact ◽  
Quantitative Methods ◽  
Economic Impacts ◽  
Economic Assessment ◽  
Simple Method ◽  
American Council On Education ◽  
Short And Long Term ◽  
Time Frames

Background: Canadian distributed medical education (DME) increased substantially in the last decade, resulting in positive economic impacts to local communities. A reliable and simple method to estimate economic contributions is essential to provide managers with information on the extent of these impacts. This review paper fills a gap in the literature by answering the question: What are the most applicable quantitative methods to assess the economic impact of Canadian DME programs?Methods: The literature is reviewed to identify economic assessment methods. These are evaluated and compared based on the benefits, challenges, data needs, outputs and potential for use in the DME context.Results: We identified five economic impact methods used in similar contexts. Two of these methods have the potential for Canadian DME programs: the Canadian Input-Output (I-O) model and the Simplified American Council on Education (ACE) method.Conclusion: Choice of a method is contingent on the ability to measure the salient economic impacts, and provide an output that facilitates sustainable decision making. This paper thus fills a gap by identifying methods applicable to DME. These methods will assist stakeholders to calculate economic impacts, resulting in both the advancement and sustainability of these programs over short- and long-term time frames.

Sign in / Sign up

Export Citation Format

Share Document