Extraction of nitrogen from soils

Wheatley, Ron E.; Macdonald, R. L.; Smith, Angela M.

doi:10.1007/bf00257765

Cited by 58 publications

(23 citation statements)

References 5 publications

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“…Soils were extracted with 1 M KCl (soil:extractant ratio 1:4) and filtered through Whatman No. 1 filter paper (Wheatley et al, 1989). Then NO 3 À -N and NH 4 + -N concentrations were determined colourimetrically on a segmented flow autoanalyser (Skalar Analytical, Breda, The Netherlands).…”

Section: Methodsmentioning

confidence: 99%

Spatial pattern and species richness of boreonemoral forest understorey and its determinants—A comparison of differently managed forests

Moora

Daniell²,

Kalle

et al. 2007

Forest Ecology and Management

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Section: Methodsmentioning

confidence: 99%

Spatial pattern and species richness of boreonemoral forest understorey and its determinants—A comparison of differently managed forests

Moora

Daniell²,

Kalle

et al. 2007

Forest Ecology and Management

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“…Soil samples were collected from a depth of 5–10 cm and then stored at 4 °C. Extractions of and were performed immediately and then soils were dried at 105 °C for 4 days, before reweighing to allow determination of water content.and, respectively, were extracted in water and in 1 m KCl (Wheatley et al . 1989).…”

Section: Methodsmentioning

confidence: 99%

A test of the indirect facilitation model in a temperate hardwood forest of the northern French Alps

Pagés¹,

Michalet²

2003

Journal of Ecology

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Summary 1We tested the hypothesis that the more frequent occurrence of tree seedlings below the adult trees than in canopy openings might be explained by indirect facilitation. In a temperate hardwood forest, we compared the performance of five target tree seedlings ( Picea abies , Abies alba , Fagus sylvatica , Acer pseudoplatanus and Quercus petraea ), transplanted with or without a herbaceous competitor ( Molinia caerulea ), either within the forest or into experimentally created gaps. 2 We quantified changes in understorey biomass, light penetration and available forms of soil nitrogen during three growing seasons. 3 Photosynthetic photon flux density and total biomass of Molinia were significantly higher in the gap treatment than within the forest. Total available nitrogen was higher in the gaps in the absence of Molinia , but higher in the forest in the presence of Molinia . 4 Quercus survival was very low within the forest because of fungal infection, whereas survival was very high for the four other tree species in all combinations of the two treatments. 5 Although the competitive effect of Molinia on the growth of the tree seedlings was much greater in the gap treatment, seedling growth was lower within the forest. We conclude that the tree canopy imposed strong light competition, and that this direct negative influence was much greater than any indirect positive effect of increased availability of nutrients to tree seedlings, due to reduced nutrient uptake by Molinia . 6 Target species responses to treatments were similar, despite strong differences in nitrogen requirements between species. This may be due to the overwhelming negative influence of the tree canopy in our experiment.

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“…Extractions of NO 3 À and NH 4 + were peformed immediately and then soils were dried at 105°C for 4 days for water content measurements. NO 3 À and NH 4 + were extracted respectively in water and in KCl 1 M, and then stored at À18°C (Wheatley et al 1989). NO 3 À was determined by ionic chromatography (Dionex 4500i) and NH 4 + with the blue indophenol method (Dorich and Nelson 1983).…”

Section: Data Collection and Compilationmentioning

confidence: 99%

Contrasted Responses of Two Understorey Species to Direct and Indirect Effects of a Canopy Gap

Pagés

Michalet

2006

Plant Ecol

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Positive associations between adult trees and understorey species have been explained either by direct or indirect facilitation. We tested both models by comparing the performance of two understorey species with contrasted stress-tolerance abilities Galium odoratum and Deschampsia flexuosa. Individuals of both species were transplanted in the four combinations of two treatments (gap and removal of an herbaceous competitor, Molinia caerulea). Our experiment demonstrated that direct facilitation of adult trees may explain the restricted occurrence of the shade-demanding Galium within closed forest communities. In contrast, the shade-tolerant Deschampsia was subjected to additional competition within the forest, likely because adult trees had a higher negative effect on light availability and a similar negative effect on nitrogen availability within the forest than did Molinia in the gaps.

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Extraction of nitrogen from soils

Cited by 58 publications

References 5 publications

Spatial pattern and species richness of boreonemoral forest understorey and its determinants—A comparison of differently managed forests

Spatial pattern and species richness of boreonemoral forest understorey and its determinants—A comparison of differently managed forests

A test of the indirect facilitation model in a temperate hardwood forest of the northern French Alps

Contrasted Responses of Two Understorey Species to Direct and Indirect Effects of a Canopy Gap

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