Effect of three soil tillage intensities on the activity of mycorrhizal fungi in two soils in Switzerland.

MOZAFAR, AHMAD¹, HAMID MEHRAVARAN², RICHARD RUH¹, THOMAS ANKEN³ & EMMANUEL FROSSARD¹

¹Swiss Federal Institute of Technology (ETH), Institute of Plant Sciences, Eschikon Experiment Station, CH-8315 Lindau, SWITZERLAND. ²Department of Agronomy, College of Agriculture, Uroumieh University, Uroumieh, IRAN. ³Swiss Federal Research Station for Agricultural Economics and Engineering, CH-8356 Tänikon, SWITZERLAND.

The effect of soil tillage intensity on the activity of mycorrhizal fungi was studied. The site was Tänikon Experiment Station (46°30 N; 8°50 E) in Switzerland where a long-term tillage trial is in progress since 1987. At this site there are three tillage intensities (no-till, chisel and plow) at two locations (Langwiese with clay-loam and Hausweid with sandy loam soil) with four replications in each location. The rotation is winter wheat, maize, winter wheat and rapeseed. During the 1996 we took soil, root and leaf samples from the maize fields and the population of Arbuscular mycorrhizal spores in the soil, degree of mycorrhizal colonization of plant roots and nutrient concentration in the leaves were investigated. Locations were different in the total number of AM spores. Tillage intensity did not affect the total number of AM spores. There seems to be relatively more smaller AM spores in fields under no-till treatment. Maize roots in no-till fields were colonized by AM fungi much earlier in the season and much more during the whole season. Maize leaves in the no-till plots contained higher concentrations of P, Cu and Zn and less Mn as compared with plants in the plowed fields.