THE ROLE OF SOIL NITROGEN IN THE GROWTH OFTREES ON DERELICT LAND

Summary

Derelict and urban soils often have many unusual properties including extreme nitrogen deficiency. In order to determine the implications of low nutrient levels it is necessary to assess the minimum N requirement for tree growth. A literature review and site survey data from china clay waste suggest that approximately 800–1000 kg N Ha⁻¹ is required for the most unproductive woodlands.

The paper considers the potential for using nitrogen-fixing trees to supply adequate N to support other species on clay waste. Their efforts on soil and on adjacent trees is measured. Alternative strategies shown by trees for withstanding low nutrient conditions may be less beneficial.