Non-Symbiotic Nitrogen Fixation in a Soil of the Nigerian Rain-Forest Zone

Abstract

COMPARATIVELY little is known of the contribution of non-symbiotic nitrogen fixation to the nitrogen economy of tropical soils. In the tropical rain-forest areas it is generally considered that the soil nitrogen supply, depleted by arable cropping, is built up again during the period of ‘bush fallow’, presumably by indigenous legumes (and perhaps certain non-legumes) present in the regrowth. That appreciable non-symbiotic nitrogen fixation may occur in the soils of this area was shown in the experiment described here.