The study investigated the possibilities of promoting utilization of arbuscular mycorrhiza (AM) in crop P nutrition in Northern European conditions by decreasing P fertilization. The effect of two contrasting long-term P fertilization regimes on fungal (AMF) infectivity, on contribution of AM to crop growth and nutrient uptake, and on P and N responses was investigated in bioassays in a growth chamber with the original field soil. A control with suppressed AM was successfully created by benomyl application. Functional properties of the field AMF communities were
compared after back- and cross-inoculation to the irradiated field soils. The two long-term field experiments that were utilized represented clay and loam soils and P levels from low to high. The results show that annual dressings of soluble inorganic P fertilizers, even in moderate amounts, decrease the infectivity and effectiveness of AMF communities of Northern European field soils.
Helena Kahiluoto Agricultural Research Centre of Finland
Elise Ketoja Ecological Production, Partala, FIN-51900 Juva, Finland
Mauritz Vestberg Data and Information Services, FIN-31600 Jokioinen, Finland
Copyright:Plant and Soil 227: 191–206, 2000.
© 2000 Kluwer Academic Publishers. Printed in the Netherlands.