Long‐term Soil Tillage and Cover Cropping Affected Arbuscular Mycorrhizal Fungi, Nutrient Concentrations, and Yield in Sunflower

Abstract

Core Ideas Novel insights in the arbuscular mycorrhizal fungi tillage cover crop interaction based on a long term trial. Cover crops and soil tillage affect arbuscular mycorrhizal fungi colonization in the subsequent main crop. Nutrient concentrations and C/N ratio were affected by soil tillage. Reduction of soil tillage and whole‐year coverage are major factors for sustainable agriculture. Arbuscular mycorrhizal fungi (AMF) are major components of the native soil microbiome in agricultural soils. Soil tillage and cover cropping can play an important role in promoting AMF abundance. In the present study, the results of a field experiment comprising different soil tillage treatments (conventional, reduced, minimum, no‐tillage) in interaction with cover cropping (comprising AMF host and nonhost plants) in a common crop rotation with Triticum aestivum (winter wheat) and Helianthus annuus (sunflower) as the main crops are presented. Different cover crops (in mixtures or as single components) were cultivated in an existing soil tillage experiment established in 2009 in Austria. Soil tillage affected mycorrhization of winter wheat but not of cover crops. A different AMF root colonization were found in several cover crop species and in the subsequent sunflower. In this crop, AMF root colonization and spore density was further affected by soil tillage. The grain yields of the main crops were not altered by soil tillage. Significant interactions of soil tillage and cover cropping were found in the yield of sunflower and the C/N ratios. Furthermore, the nutrient concentrations of the plants were affected by soil tillage. This study shows that reduced soil tillage intensity combined with cover cropping enhances the abundance of AMF in the soil and affects the yield of the following main crop. Notably, mycorrhizal nonhost plants as cover crops do not lead to negative conditions for AMF in a common crop rotation.