Agricultural management and pesticide use reduce the functioning of beneficial plant symbionts

Combining field data and greenhouse experiments, the authors show how agricultural management practices like fungicide applications can affect the degree to which arbuscular mycorrhizal fungi in the soil provision phosphorus to plants. Phosphorus (P) acquisition is key for plant growth. Arbuscular mycorrhizal fungi (AMF) help plants acquire P from soil. Understanding which factors drive AMF-supported nutrient uptake is essential to develop more sustainable agroecosystems. Here we collected soils from 150 cereal fields and 60 non-cropped grassland sites across a 3,000 km trans-European gradient. In a greenhouse experiment, we tested the ability of AMF in these soils to forage for the radioisotope P-33 from a hyphal compartment. AMF communities in grassland soils were much more efficient in acquiring P-33 and transferred 64% more P-33 to plants compared with AMF in cropland soils. Fungicide application best explained hyphal P-33 transfer in cropland soils. The use of fungicides and subsequent decline in AMF richness in croplands reduced P-33 uptake by 43%. Our results suggest that land-use intensity and fungicide use are major deterrents to the functioning and natural nutrient uptake capacity of AMF in agroecosystems.

Automated summary

By combining field data and greenhouse experiments, the authors demonstrate the impact of agricultural management practices, such as fungicide applications, on the provision of phosphorus to plants by arbuscular mycorrhizal fungi (AMF) in the soil. Their research suggests that AMF in grassland soils are more efficient in acquiring and transferring phosphorus to plants compared to AMF in cropland soils, which are affected by fungicide use. These findings highlight the importance of land-use intensity and fungicide application in determining the functioning and natural nutrient uptake capacity of AMF in agroecosystems.