Agroscope describes how AMF form a symbiotic association with plants, supplying them with phosphorus and other elements. “This free service provided by nature must be looked after, since it helps keep the soil healthy and can contribute to plant yield,” it adds.

Agroscope, FiBL, INRAE (France) and the universities of Zurich (Switzerland), Berlin (Germany), Greenwich (UK), Madrid (Spain) and Uppsala (Sweden) studied arable and grassland soils throughout Europe and conducted experiments in greenhouses. Agroscope reports: “Their aim: to discover from two studies the conditions under which AMF pass on the most phosphorus to plants, and what factors influence the amount and diversity of these beneficials in the field.”

Agroscope reports that the first study showed that AMF in grassland are more efficient at passing on phosphorus to plants than AMF in arable land. This is due, it says, to tillage, fertilisation and fungicide use, which reduce the diversity and quantities of AMF in addition to hindering their ability to establish a symbiotic relationship with plant roots. Agroscope adds: “Furthermore, the study showed that in fields where fungicides were used, AMF imparted on average 43% less phosphorus to plants than in arable soils without fungicide use.”

Agroscope also reports a second study examining plant protection product residues across 100 arable and vegetable crop fields in Switzerland. It reports: “Plant protection product residues were found in all of the tested soils, their numbers ranging from 3 to 32; however, in vegetable production the concentrations were on average 79% higher than in arable soils.

“On average, 85% fewer residues were found in organic soils, whether used for arable or vegetable production. Nevertheless, the value never fell to zero. Even twenty years after conversion to organic production, up to 16 plant protection products could be detected in the soil.”

Agroscope adds: “In addition, these two studies confirmed that plant protection products had a negative effect on AMF; the more plant protection product residues in the soil, the less AMF were to be found there.”

For more information:

• Read the full story, including key conclusions, on the Agroscope website here
• Read the scientific article: Agricultural management and pesticide use reduce the functioning of beneficial plant symbionts