Long-term diverse straw management influences arbuscular mycorrhizal fungal community structure and plant growth in a rice-rotated wheat cropping system.

Communities of arbuscular mycorrhizal fungi (AMF) in soil are influenced by various agricultural managements, which in turn affects crop productivity. However, the impacts of straw returning on AMF communities are sparsely understood. Here, a 7-year field experiment including three sets of straw managements - returning methods (CK: no-tillage without straw; RT-SR: rotary tillage with straw; DB-SR: ditch-buried tillage with straw), burial amount, burial depth - were applied to evaluate the influences of straw managements on AMF composition. With full amounts of straw return, AMF diversity was similar between DB-SR and CK at a depth of 20 cm, whilst it was 13% higher than that under RT-SR. This could be explained by the increased rhizodeposition under DB-SR may counterbalance the negative effect of tillage under RT-SR on AMF hyphal growth. DB-SR changed AMF composition and enhanced the abundance of Glomeraceae, as well as the amount of glomalin-related protein, as a consequence increased plant P uptake by 68% than RT-SR. DB-SR remained stable plant P uptake and wheat biomass at a burial depth of 40 cm, but it decreased AMF diversity and the abundance of Glomeraceae as compared to DB-SR at a burial of 20 cm. This indicated DB-SR at a burial depth of 40 cm may be not beneficial to crop growth. Our results suggest that ditch-buried straw return with a depth of 20 cm and full amounts of straws is promising to improve soil health (via regulating AMF community diversity and composition) and promote crop production (via increasing plant P uptake).