Soil as a potential source of nitrogen for mat-forming lichens

2004 ◽  
Vol 82 (1) ◽  
pp. 145-149 ◽  
Author(s):  
Christopher J Ellis ◽  
Peter D Crittenden ◽  
Charles M Scrimgeour
Keyword(s):  
Field Experiment ◽  
Soil Nutrients ◽  
Vascular Plants ◽  
Organic Nitrogen ◽  
N Uptake ◽  
Soil Surface ◽  
Organic N ◽  
Soil N ◽  
Potential Source ◽  
Efficient Uptake

A field experiment is described, the aim of which was to assess the extent of nitrogen (N) movement from heathland soil upwards into terricolous mat-forming lichens. A molten agar solution of either 15N-labelled glycine or 15N-labelled ammonium (as NH4Cl) was injected onto the soil surface beneath undisturbed cushions of Cladonia por tentosa (Dufour) Coem. Lichen thalli were recovered after 9 months and analysed for 15N content. There was no evidence of 15N uptake by the lichen, though 15N was taken up by vascular plants rooted beneath the lichen cushions. The results suggest that C. portentosa does not compete effectively for soil N. This refutes the conclusions of previous studies, which inferred the efficient uptake of soil organic N by mat-forming lichens based on values of δ15N.Key words: ammonium, lichens, 15N, organic nitrogen, soil nutrients.

scholarly journals Do plants use root-derived proteases to promote the uptake of soil organic nitrogen?

2020 ◽  
Vol 456 (1-2) ◽  
pp. 355-367
Author(s):  
Lucy M. Greenfield ◽  
Paul W. Hill ◽  
Eric Paterson ◽  
Elizabeth M. Baggs ◽  
Davey L. Jones
Keyword(s):  
Protease Activity ◽  
Organic Nitrogen ◽  
N Uptake ◽  
Root Surface ◽  
Organic N ◽  
Soil Organic Nitrogen ◽  
Poor Access ◽  
N Deficiency ◽  
Almost All ◽  
Soil Protein

Abstract Aims The capacity of plant roots to directly acquire organic nitrogen (N) in the form of oligopeptides and amino acids from soil is well established. However, plants have poor access to protein, the central reservoir of soil organic N. Our question is: do plants actively secrete proteases to enhance the breakdown of soil protein or are they functionally reliant on soil microorganisms to undertake this role? Methods Growing maize and wheat under sterile hydroponic conditions with and without inorganic N, we measured protease activity on the root surface (root-bound proteases) or exogenously in the solution (free proteases). We compared root protease activities to the rhizosphere microbial community to estimate the ecological significance of root-derived proteases. Results We found little evidence for the secretion of free proteases, with almost all protease activity associated with the root surface. Root protease activity was not stimulated under N deficiency. Our findings suggest that cereal roots contribute one-fifth of rhizosphere protease activity. Conclusions Our results indicate that plant N uptake is only functionally significant when soil protein is in direct contact with root surfaces. The lack of protease upregulation under N deficiency suggests that root protease activity is unrelated to enhanced soil N capture.

The Potential Availability of Organic Nitrogen Fractions in Some West Indian Soils

1968 ◽  
Vol 4 (3) ◽  
pp. 193-201 ◽  
Author(s):  
I. S. Cornforth
Keyword(s):  
Organic Nitrogen ◽  
N Uptake ◽  
Acid Soils ◽  
West Indian ◽  
Greenhouse Experiment ◽  
Organic N ◽  
Available N ◽  
Indian Soils ◽  
Potential Availability ◽  
Hydrolysable N

SummaryThe effect of four crops of maize on the distribution of organic nitrogen in ten West Indian soils, given either lime, P, K, Mg and trace elements or no fertilizers, was studied in a greenhouse experiment. The soils were also analysed for ‘available N’ by incubation and chemical methods. Variations in the redistribution of organic N fractions during the greenhouse experiment did not permit conclusions to be drawn on the source of N used by the maize, although the amount of hydrolysable N, particularly hexosamine, amino and hydroxy-amino N, in the initial samples was closely related to N uptake. Part of the chemically stable, non-hydrolysable organic N was broken down by soil organisms during the experiment; this was increased by liming acid soils.

Integrated management of straw and urea nitrogen in lowland rice under a rice-wheat rotation

1991 ◽  
Vol 116 (2) ◽  
pp. 217-220 ◽  
Author(s):  
B. S. Mahapatra ◽  
G. L. Sharma ◽  
Nayab Singh
Keyword(s):  
Field Experiment ◽  
Integrated Management ◽  
N Uptake ◽  
Residual Effects ◽  
Organic N ◽  
Rice Grain ◽  
Split Application ◽  
Inorganic N ◽  
Rice Yields ◽  
Straw Application

SUMMARYThe average yields of a 3-year field experiment (1985/86–1987/88) on a mollisol at Pantnagar showed that, at 87 kg N/ha, applying urea supergranules (USG) gave 0·47 t/ha more rice grain than split application of prilled urea (PU). The data also showed that, at this rate of N, one-third (29 kg N/ha) of inorganic N can be substituted by fresh straw (wheat or rice) applied at planting to give similar rice yields. However, at a total of 58 kg N/ha, 29 kg N/ha applied as straw with 29 kg N/ha of PU or USG reduced yield compared with 58 kg N/ha of PU or USG alone, except in 1986/87. Yield differences were attributed to differences in number of panicles/m2, N uptake by the crop and mean wet soil NH4+-N obtained at various stages of crop growth during 1986/87 and 1987/88. Wheat grown after rice in 1985/86 and 1986/87 showed significant residual effects in plots with straw application and these were correlated with the rate of hydrolysable organic N (HN) obtained after rice.

COMPARAISON DE DIFFÉRENTES MÉTHODES D'ANALYSE DE L'AZOTE DU SOL EN RELATION AVEC SA DISPONIBILITÉ POUR LES PLANTES

1987 ◽  
Vol 67 (3) ◽  
pp. 521-531 ◽  
Author(s):  
M. GIROUX ◽  
T. SEN TRAN
Keyword(s):  
Organic Matter ◽  
Soil Nitrogen ◽  
N Uptake ◽  
Relative Yield ◽  
Organic N ◽  
Uv Absorbance ◽  
Soil N ◽  
Plant N Uptake ◽  
Total N ◽  
N Concentration

The objective of this study was to compare several methods of estimating the availability of soil nitrogen to plants. Total soil N, organic matter content, mineralized N during a 2 wk incubation at 35 °C, organic N in 6 N HC1, 0.01 M NaHCO3 and 1 N KCl extracts, and finally mineral N extracted by 2 N KCl were evaluated and contrasted with N uptake by sugar beets cultivated on 19 soils in a greenhouse experiment. The relative yield or plant N uptake gave the highest correlation coefficients when both mineral and organic N fractions in soil extract were considered. The incubation methods gave the best correlation coefficient with relative yield (R2 = 0.85**). N contents in NaHCO3 extract were more correlated with relative yield or N uptake than total N, organic matter contents or N extracted by 6 N HCl or 1 N KCl. The UV absorbance values obtained at 205 nm with 0.01 M NaHCO3 extract were also well correlated with relative yield (R2 = 0.78**) and plant N uptake (R2 = 0.66**). At this wavelength, as well as at 220 nm, the absorbance was affected by mineral and organic N contents in the extract. However, at 260 nm, the UV absorbance was only related to organic N in the extract; consequently these absorbance values were less correlated with relative yield (R2 = 0.49**) or N uptake (R2 = 0.27*). Furthermore, the absorbance measured at 205 nm was too sensitive to NO3-N and organic N concentration and this relationship was not linear in the high-N concentration range. The UV absorbance at 220 nm in the 0.01M NaHCO3 extract seemed to be a promising method to evaluate the availability of soil N. Key words: Soil nitrogen, incubation, ultraviolet absorbance, hydrolyzable nitrogen

scholarly journals Agricultural Nitrogen Budget for a Long-Term Row Crop Production System in the Midwest USA

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1622
Author(s):  
Sanku Dattamudi ◽  
Prasanta K. Kalita ◽  
Saoli Chanda ◽  
A.S. Alquwaizany ◽  
B. S.Sidhu
Keyword(s):  
Environmental Sustainability ◽  
Surface Runoff ◽  
Crop Production ◽  
N Uptake ◽  
Soil Surface ◽  
Fertilizer Application ◽  
Soil N ◽  
Entire Study ◽  
Tile Drains

In the Midwestern United States, subsurface drainage (commonly known as tile drains) systems have been extensively used for sustaining agricultural production. However, the tile drains have raised concerns of facilitating the transport of agricultural chemicals from the fields to receiving waters. Data from a long-term field experiment in the Little Vermilion River (LVR) watershed of east-central Illinois, USA, shows that the tile drain systems have contributed to increased nitrate N (NO3-N) to the receiving water body, Georgetown Lake Reservoir, over time. We conducted more than 10 years of research on fate and transport of NO3-N in tile drain water, surface runoff and soil N. Corn (Zea mays L.) and soybean (Glycine max L.) were planted in rotation for this watershed. We evaluated N balance (inputs and outputs) and transfer (runoff and leaching) components from three sites with both surface and subsurface flow stations within this watershed, and N budgets for individual sites were developed. Nitrogen fertilizer application (average 192 kg ha−1 y−1) and soil N mineralization (average 88 kg ha−1 y−1) were the major N inputs for corn and soybean, respectively in this watershed. Plant N uptake was the major N output for both crops during this entire study period. Annual N uptake for the LVR watershed ranged from +39 to +148 (average +93) kg ha−1 and −63 to +5 (average −32) kg ha−1, respectively, for corn and soybeans. This data indicates that most of the soil mineralized N was used during soybean production years, while corn production years added extra N in the soil. Surface runoff from the watershed was negligible, however, subsurface leaching through tile drains removed about 18% of the total rainfall. Average NO3-N concentrations of leaching water at sites A (15 mg L−1) and B (16.5 mg L−1) exceeded maximum contaminant level (MCL; 10 mg L−1) throughout the experiment. However, NO3-N concentrations from site E (6.9 mg L−1) never exceeded MCL possibly because 15–22% lower N was received at this site. We estimated that the average corn grain yield would need to be 28% higher to remove the additional N from this watershed. Our study suggests that N application schemes of the LVR watershed need to be reevaluated for better N management, optimum crop production, and overall environmental sustainability.

scholarly journals Bermudagrass Management in the Southern Piedmont U.S. IV. Soil Surface Nitrogen Pools

2001 ◽  
Vol 1 ◽  
pp. 673-681 ◽  
Author(s):  
Alan J. Franzluebbers ◽  
John A. Stuedemann
Keyword(s):  
Cynodon Dactylon ◽  
Soil Surface ◽  
N Fertilization ◽  
Organic N ◽  
Soil N ◽  
Crimson Clover ◽  
Total Soil ◽  
Soil N Pools ◽  
Total Soil N

The fate of nitrogen (N) applied in forage-based agricultural systems is important for understanding the long-term production and environmental impacts of a particular management strategy. We evaluated the factorial combination of three types of N fertilization (inorganic, crimson clover [Trifolium incarnatum L.] cover crop plus inorganic, and chicken [Gallus gallus] broiler litter pressure and four types of harvest strategy (unharvested forage, low and high cattle [Bos Taurus] grazing pressure, and monthly haying in summer) on surface residue and soil N pools during the first 5 years of ̒Coastal̓ bermudagrass (Cynodon dactylon [L.] Pers.) management. The type of N fertilization used resulted in small changes in soil N pools, except at a depth of 0 to 2 cm, where total soil N was sequestered at a rate 0.2 g ‧ kg–1‧ year–11 greater with inorganic fertilization than with other fertilization strategies. We could account for more of the applied N under grazed systems (76–82%) than under ungrazed systems (35–71%). As a percentage of applied N, 32 and 48% were sequestered as total soil N at a depth of 0 to 6 cm when averaged across fertilization strategies under low and high grazing pressures, respectively, which was equivalent to 6.8 and 10.3 g ‧ m–2‧ year–1. Sequestration rates of total soil N under the unharvested-forage and haying strategies were negligible. Most of the increase in total soil N was at a depth of 0 to 2 cm and was due to changes in the particulate organic N (PON) pool. The greater cycling of applied N into the soil organic N pool with grazed compared with ungrazed systems suggests an increase in the long-term fertility of soil.

scholarly journals Green Manuring Effect on Changes of Soil Nitrogen Fractions, Maize Growth, and Nutrient Uptake

Agronomy ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 261 ◽  
Author(s):  
Lu Yang ◽  
Jinshun Bai ◽  
Jia Liu ◽  
Naohua Zeng ◽  
Weidong Cao
Keyword(s):  
Green Manure ◽  
N Uptake ◽  
Partial Substitution ◽  
Organic N ◽  
Soil N ◽  
Path Modeling ◽  
Mineral N ◽  
N Accumulation ◽  
Maize Growth ◽  
N Fractions

Green manure is a promising, at least partial, substitution for chemical fertilizer in agriculture, especially for nitrogen (N), which in soil can be radically changed by exogenous input. However, it is not well understood how, after green manure incorporation, soil N changes coordinate with crop N uptake and consequently contribute to fertilizer reduction in a maize–green manure rotation. A four-year field study was performed consisting of (1) control, no fertilization; (2) F100, recommended inorganic fertilization alone; (3) G, green manure incorporation alone; (4) F70 + G (70% of F100 plus G); (5) F85 + G; and (6) F100 + G. The results show that treatments with 15–30% reduction of inorganic fertilizer (i.e., F70 + G and F85 + G) had similar grain yield, dry matter (DM) accumulation, and N uptake as F100 treatment. F100 + G maize had 17% greater DM and 15% more N uptake at maturity relative to F100. Of the five soil N fractions examined, dissolved organic N (DON) and mineral N (Nmin) explained over 70% of the variation of maize DM and N accumulation. Partial least squares path modeling further revealed that soil N fractions had positive indirect effects on DM production through N uptake, which might be coordinated with improved DON and Nmin status at both early and mid-late stages of maize growth. Overall, the results highlight enhanced maize production with reduced fertilizer inputs based on green manure incorporation in temperate regions.

Ectomycorrhizal fungi and the nitrogen economy of conifers — implications for genecology and climate change mitigation

Botany ◽  
2014 ◽  
Vol 92 (6) ◽  
pp. 417-423 ◽  
Author(s):  
J.M. Kranabetter
Keyword(s):  
Climate Change ◽  
Climate Change Mitigation ◽  
N Uptake ◽  
Organic N ◽  
Soil N ◽  
N Supply ◽  
Wide Range ◽  
Forest Genetic ◽  
Spatial Attributes ◽  
Change Mitigation

The nitrogen (N) economy of conifers is hypothesized to reflect three spatially defined and interacting sources of variability in forest nutrition. These include the physiological adaptations of the host tree (N uptake capacities among populations), matched to the particular amount and nature of soil N supply (organic N, NH4+, and NO3–), as mediated by communities of site-adapted ectomycorrhizal (EM) fungi. The spatial attributes of an N economy may vary considerably over the ranges of tree species because of wide gradients in climate and soil fertility, underpinning a potentially important aspect of conifer genecology with implications for climate change mitigation. The evidence for an intersection of N supply with host demand, as mediated by EM fungi, will be briefly reviewed and then evaluated in light of assisted migration studies involving provenance trials of coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) in southwestern British Columbia. The trials were established across a wide range of site types, and so they provide valuable data on host response to gradations in soil N supply and interactions with local EM fungal communities. Preliminary results and knowledge gaps will be discussed under the framework of an N economy and management of forest genetic resources.

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

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.

scholarly journals Effects of two wood-based biochars on the fate of added fertilizer nitrogen—a 15N tracing study

2021 ◽  
Author(s):  
Subin Kalu ◽  
Gboyega Nathaniel Oyekoya ◽  
Per Ambus ◽  
Priit Tammeorg ◽  
Asko Simojoki ◽  
...  
Keyword(s):  
Plant Uptake ◽  
Plant Biomass ◽  
Application Rate ◽  
Control Treatment ◽  
Organic N ◽  
N Leaching ◽  
Soil N ◽  
Mineral N ◽  
Total N ◽  
Application Rates

AbstractA 15N tracing pot experiment was conducted using two types of wood-based biochars: a regular biochar and a Kon-Tiki-produced nutrient-enriched biochar, at two application rates (1% and 5% (w/w)), in addition to a fertilizer only and a control treatment. Ryegrass was sown in pots, all of which except controls received 15N-labelled fertilizer as either 15NH4NO3 or NH415NO3. We quantified the effect of biochar application on soil N2O emissions, as well as the fate of fertilizer-derived ammonium (NH4+) and nitrate (NO3−) in terms of their leaching from the soil, uptake into plant biomass, and recovery in the soil. We found that application of biochars reduced soil mineral N leaching and N2O emissions. Similarly, the higher biochar application rate of 5% significantly increased aboveground ryegrass biomass yield. However, no differences in N2O emissions and ryegrass biomass yields were observed between regular and nutrient-enriched biochar treatments, although mineral N leaching tended to be lower in the nutrient-enriched biochar treatment than in the regular biochar treatment. The 15N analysis revealed that biochar application increased the plant uptake of added nitrate, but reduced the plant uptake of added ammonium compared to the fertilizer only treatment. Thus, the uptake of total N derived from added NH4NO3 fertilizer was not affected by the biochar addition, and cannot explain the increase in plant biomass in biochar treatments. Instead, the increased plant biomass at the higher biochar application rate was attributed to the enhanced uptake of N derived from soil. This suggests that the interactions between biochar and native soil organic N may be important determinants of the availability of soil N to plant growth.

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