Mycorrhizal infection in Pennine grassland. 1. Levels of infection in the field.
Abstract
Roots collected from 3 contrasting types of permanent grassland in the Pennines were consistently infected by vesicular-arbuscular (VA) mycorrhizal fungi. About half of the root material with cortex was infected and there was little variation in infection with soil depth. Seasonal changes in infection were small. The greatest total wt. of root and total wt. of infected root occurred in summer, although the highest levels of infection were in winter. Spores of the VA fungi were not common and it is likely that many of them are non-sporing forms. Top-dressings of P fertilisers (250 kg P/ha) decreased mycorrhizal infection during the 1st yr of application, but this effect declined after 2 yr at 2 of the sites. Lime, N and K dressings did not appreciably affect the amount of mycorrhizal infection.<new para>ADDITIONAL ABSTRACT:<new para>About half of the collected root material with cortex was infected with vesicular-arbuscular (VA) mycorrhizal fungi. The greatest total wt. of root and of infected root occurred in summer, although levels of infection were highest in winter. Spores of the VA fungi were not common; many may be non-sporing forms. Top dressing of phosphate fertilisers (250 kg P/ha) decreased mycorrhizal infection during the 1st yr of application, but this effect declined after 2 yr at 2 of the sites.