Long-term increase of nitrogen availability from fertilization of Douglas-fir

Most Douglas-fir stands respond to nitrogen fertilization by increasing stem growth for less than 8 years, but one plantation at the United States Forest Service Wind River Experimental Forest has responded for over 15 years. The nitrogen concentration of foliage and fresh litter were higher in the fertilized (applied at 470 kg N/ha) plots 18 years after fertilization. Retranslocation of N from senescent needles was not affected and stem growth per unit N in the canopy was similar between unfertilized and fertilized plots. An index of soil N availability in the fertilized plots was twice that of unfertilized plots. The higher stem growth, leaf area, and stem growth per unit leaf area appeared related to a sustained increase in soil N availability rather than increased N-use efficiency. Soil N transformation processes need to be examined to complete the explanation of the unusually prolonged fertilizer response in these plots.

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Carbon Mineralization in a Soil Amended with Sewage Sludge-Derived Biochar

Applied Sciences ◽

10.3390/app9214481 ◽

2019 ◽

Vol 9 (21) ◽

pp. 4481 ◽

Cited By ~ 3

Author(s):

Figueiredo ◽

Coser ◽

Moreira ◽

Leão ◽

Vale ◽

...

Keyword(s):

Sewage Sludge ◽

Co2 Emissions ◽

Nitrogen Availability ◽

Carbon Mineralization ◽

Environmental Benefits ◽

N Availability ◽

Soil N ◽

Total N ◽

Soil N Availability ◽

Organic Matter Stabilization

Biochar has been presented as a multifunctional material with short- and long-term agro-environmental benefits, including soil organic matter stabilization, improved nutrient cycling, and increased primary productivity. However, its turnover time, when applied to soil, varies greatly depending on feedstock and pyrolysis temperature. For sewage sludge-derived biochars, which have high N contents, there is still a major uncertainty regarding the influence of pyrolysis temperatures on soil carbon mineralization and its relationship to soil N availability. Sewage sludge and sewage sludge-derived biochars produced at 300 °C (BC300), 400 °C (BC400), and 500 °C (BC500) were added to an Oxisol in a short-term incubation experiment. Carbon mineralization and nitrogen availability (N-NH4+ and N-NO3−) were studied using a first-order model. BC300 and BC400 showed higher soil C mineralization rates and N-NH4+ contents, demonstrating their potential to be used for plant nutrition. Compared to the control, the cumulative C-CO2 emissions increased by 60–64% when biochars BC300 and BC400 were applied to soil. On the other hand, C-CO2 emissions decreased by 6% after the addition of BC500, indicating the predominance of recalcitrant compounds, which results in a lower supply of soil N-NH4+ (83.4 mg kg−1) in BC500, being 67% lower than BC300 (255.7 mg kg−1). Soil N availability was strongly influenced by total N, total C, C/N ratio, H, pore volume, and specific surface area in the biochars.

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Spatial extent of impact of red alder on soil chemistry of adjacent conifer stands

Canadian Journal of Forest Research ◽

10.1139/x92-192 ◽

1992 ◽

Vol 22 (9) ◽

pp. 1434-1437 ◽

Cited By ~ 16

Author(s):

Charles C. Rhoades ◽

Dan Binkley

Keyword(s):

Soil Ph ◽

Soil Chemistry ◽

Douglas Fir ◽

Spatial Extent ◽

N Availability ◽

Soil N ◽

Mixed Stands ◽

Red Alder ◽

Soil N Availability ◽

River Site

We examined patterns in soil N availability and pH along transects extending from mixed stands of conifers (mostly Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco)) and red alder (Alnusrubra Bong.) to pure conifer stands at two locations. At the relatively infertile Wind River site, increased N availability was apparent for about 8–12 m downslope of the alder–conifer stand, but no effect was apparent upslope. At the fertile Cascade Head site, no trend was apparent in N availability across the stand boundaries, but soil pH in the conifer stand was depressed for about 5 m from the alder–conifer stand. Overall, the effects of alder on soil chemistry appeared limited to a distance of less than half the height of the trees.

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Plant controls on post-fire nitrogen availability in a pine savanna

10.5194/bg-2016-303 ◽

2016 ◽

Author(s):

Cari D. Ficken ◽

Justin P. Wright

Keyword(s):

Nitrogen Availability ◽

Inorganic Nitrogen ◽

Management Tool ◽

Sink Strength ◽

N Availability ◽

Ash Deposition ◽

Soil N ◽

Eastern United States ◽

Soil N Availability ◽

Pine Savanna

Abstract. Many ecosystems experience drastic changes to soil nutrient availability associated with fire, but the magnitude and duration of these changes are highly variable among vegetation and fire types. In pyrogenic pine savannas across the south eastern United States, pulses of soil inorganic nitrogen (N) occur in tandem with ecosystem-scale nutrient losses from prescribed burns. Despite the importance of this management tool for restoring and maintaining fire-dependent plant communities, the contributions of different mechanisms underlying fire-associated changes to soil N availability remain unclear. Pulses of N availability following fire have been hypothesized to occur through (1) changes to microbial cycling rates and (2) direct ash deposition; we further hypothesize that (3) changes to plant sink strength may contribute to ephemeral increases in soil N availability. Here, we document fire-associated changes to N availability across the growing season in a longleaf pine savanna in North Carolina. To differentiate between possible mechanisms driving soil N pulses, we measured net microbial cycling rates and changes to soil δ15N before and after a burn. We found no evidence for changes in microbial activity, and limited evidence that ash deposition could account for the increase in ammonium availability to more than 5–25 times background levels. We conclude that a temporary dampening of vegetation demand for N following fire may contribute to the observed increases in inorganic N availability.

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Soil nitrogen availability influences seasonal carbon allocation patterns in sugar maple (Acersaccharum)

Canadian Journal of Forest Research ◽

10.1139/x92-059 ◽

1992 ◽

Vol 22 (4) ◽

pp. 447-456 ◽

Cited By ~ 27

Author(s):

Marianne K. Burke ◽

Dudley J. Raynal ◽

Myron J. Mitchell

Keyword(s):

Fine Roots ◽

Sugar Maple ◽

Nitrogen Availability ◽

Fine Root ◽

Carbon Allocation ◽

Root Production ◽

N Availability ◽

Soil N ◽

Soil N Availability ◽

Allocation Patterns

The influence of soil N availability on growth, on seasonal C allocation patterns, and on sulfate-S content in sugar maple seedlings (Acersaccharum Marsh.) was tested experimentally. Relative to controls, the production of foliage doubled in response to high N availability, and the production of foliage, stems, coarse roots, and fine roots was halved in response to N deprivation. The period of foliage production was lengthened by fertilization and the period of fine root production was shortened by N deprivation compared with controls. In August, a shift in priority C allocation from foliage to roots occurred in the N-deprivation treatment. Therefore, during this month alone, the shoot to root ratio was greater in fertilized plants (1.0) than in N-deprived plants (0.5). Allocation to storage reserves was highest in N-deprived and lowest in fertilized plants (average 160 vs. 125 mg glucose/g biomass produced), and storage in roots of unfertilized plants commenced earlier (August) than in fertilized plants (after September). This resulted in unfertilized plants having higher fine root starch concentrations (5.2%) than fertilized plants (4.0%) in December, although sugar concentrations were similar (5.7%). The lengthened season of shoot growth and the low starch to sugar ratios in fine roots of fertilized plants are symptoms consistent with a higher risk of frost injury and microbial pathogen infection. Although soil N availability did not influence the sulfate-S content in foliage, N deprivation resulted in higher organic S to N ratios. This suggests that more S-containing proteins are produced when N availability is poor.

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Spraying Leaves of Pear Nursery Trees with Urea and Copper Ethylenediaminetetraacetic Acid Alters Tree Nitrogen Concentration without Influencing Tree Susceptibility to Phytophthora syringae

HortTechnology ◽

10.21273/horttech.20.2.331 ◽

2010 ◽

Vol 20 (2) ◽

pp. 331-342 ◽

Cited By ~ 1

Author(s):

S. Laywisadkul ◽

C.F. Scagel ◽

L.H. Fuchigami ◽

R.G. Linderman

Keyword(s):

Ethylenediaminetetraacetic Acid ◽

Nitrogen Concentration ◽

N Availability ◽

Soil N ◽

N Content ◽

Soil N Availability ◽

Susceptibility To Infection ◽

N Concentration ◽

Nursery Trees ◽

The Relationship

Recent field observations by growers suggest that increased nitrogen (N) content in nursery trees resulting from foliar sprays with urea in the autumn increases tree susceptibility to infection by Phytophthora syringae. We investigated the effects of soil N availability and spraying pear (Pyrus communis ‘OHF 97’) trees with combinations of urea, chelated copper ethylenediaminetetraacetic acid (CuEDTA), and phosphonate-containing fungicides on stem N concentration and susceptibility to infection by P. syringae. Increasing soil N availability increased susceptibility to P. syringae and increased N and amino acid concentration in stems. Spraying trees with urea in the autumn increased concentrations of N and amino acids in stems and had no significant effect on tree susceptibility when stems were inoculated with P. syringae before or after urea sprays. Spraying trees with CuEDTA decreased stem N concentrations and had no significant influence on tree susceptibility to P. syringae when stems were inoculated before or after CuEDTA sprays. These results suggest the relationship between tree susceptibility to P. syringae and tree N concentration may be specific to the form of N, delivery method, or timing of N applications. Trees had higher N concentrations in stems in November than in October and were more susceptible to P. syringae when inoculated in November, suggesting that environmental factors and increasing tree dormancy may be responsible for changes in susceptibility to the pathogen. Spraying trees with fungicides containing fosetyl-aluminum in October or November decreased tree susceptibility to P. syringae. The effects of fungicides containing fosetyl-aluminum on susceptibility were similar regardless of whether trees were sprayed or not with urea or CuEDTA, suggesting that these fungicides can be used in combination with urea or CuEDTA sprays for reducing disease severity caused by P. syringae without impacting growers' objective of increasing tree N content with urea or enhancing early defoliation with CuEDTA.

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Contributions of microbial activity and ash deposition to post-fire nitrogen availability in a pine savanna

Biogeosciences ◽

10.5194/bg-14-241-2017 ◽

2017 ◽

Vol 14 (1) ◽

pp. 241-255 ◽

Cited By ~ 12

Author(s):

Cari D. Ficken ◽

Justin P. Wright

Keyword(s):

Microbial Activity ◽

Nitrogen Availability ◽

Inorganic Nitrogen ◽

Management Tool ◽

Sink Strength ◽

N Availability ◽

Ash Deposition ◽

Soil N ◽

Soil N Availability ◽

Pine Savanna

Abstract. Many ecosystems experience drastic changes to soil nutrient availability associated with fire, but the magnitude and duration of these changes are highly variable among vegetation and fire types. In pyrogenic pine savannas across the southeastern United States, pulses of soil inorganic nitrogen (N) occur in tandem with ecosystem-scale nutrient losses from prescribed burns. Despite the importance of this management tool for restoring and maintaining fire-dependent plant communities, the contributions of different mechanisms underlying fire-associated changes to soil N availability remain unclear. Pulses of N availability following fire have been hypothesized to occur through (1) changes to microbial cycling rates and (2) direct ash deposition. Here, we document fire-associated changes to N availability across the growing season in a longleaf pine savanna in North Carolina. To differentiate between possible mechanisms driving soil N pulses, we measured net microbial cycling rates and changes to soil δ15N before and after a burn. Our findings refute both proposed mechanisms: we found no evidence for changes in microbial activity, and limited evidence that ash deposition could account for the increase in ammonium availability to more than 5–25 times background levels. Consequently, we propose a third mechanism to explain post-fire patterns of soil N availability, namely that (3) changes to plant sink strength may contribute to ephemeral increases in soil N availability, and encourage future studies to explicitly test this mechanism.

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Development of an Online Tool for Tracking Soil Nitrogen to Improve the Environmental Performance of Maize Production

Sustainability ◽

10.3390/su13105649 ◽

2021 ◽

Vol 13 (10) ◽

pp. 5649

Author(s):

Giovani Preza-Fontes ◽

Junming Wang ◽

Muhammad Umar ◽

Meilan Qi ◽

Kamaljit Banger ◽

...

Keyword(s):

Real Time ◽

N Uptake ◽

Growing Season ◽

Weather Data ◽

N Availability ◽

Soil N ◽

N Losses ◽

Online Tool ◽

Support Tool ◽

Soil N Availability

Freshwater nitrogen (N) pollution is a significant sustainability concern in agriculture. In the U.S. Midwest, large precipitation events during winter and spring are a major driver of N losses. Uncertainty about the fate of applied N early in the growing season can prompt farmers to make additional N applications, increasing the risk of environmental N losses. New tools are needed to provide real-time estimates of soil inorganic N status for corn (Zea mays L.) production, especially considering projected increases in precipitation and N losses due to climate change. In this study, we describe the initial stages of developing an online tool for tracking soil N, which included, (i) implementing a network of field trials to monitor changes in soil N concentration during the winter and early growing season, (ii) calibrating and validating a process-based model for soil and crop N cycling, and (iii) developing a user-friendly and publicly available online decision support tool that could potentially assist N fertilizer management. The online tool can estimate real-time soil N availability by simulating corn growth, crop N uptake, soil organic matter mineralization, and N losses from assimilated soil data (from USDA gSSURGO soil database), hourly weather data (from National Weather Service Real-Time Mesoscale Analysis), and user-entered crop management information that is readily available for farmers. The assimilated data have a resolution of 2.5 km. Given limitations in prediction accuracy, however, we acknowledge that further work is needed to improve model performance, which is also critical for enabling adoption by potential users, such as agricultural producers, fertilizer industry, and researchers. We discuss the strengths and limitations of attempting to provide rapid and cost-effective estimates of soil N availability to support in-season N management decisions, specifically related to the need for supplemental N application. If barriers to adoption are overcome to facilitate broader use by farmers, such tools could balance the need for ensuring sufficient soil N supply while decreasing the risk of N losses, and helping increase N use efficiency, reduce pollution, and increase profits.

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