Effects of soil disturbance, residue application, and arbuscular mycorrhizal (AM) symbiosis on growth of Medicago truncatula and soil water-stable aggregates

Arbuscular mycorrhizal fungi (AMF)–plant symbiosis plays an important role in agricultural ecosystems but is easily affected by agricultural practices such as tillage and plant residue retention. In this study, the effects of different AMF and their combinations on the growth of Medicago truncatula and soil water-stable aggregates (SWA) under soil disturbance/non-disturbance and residue application/non-application were investigated by simulating a crop rotation system of wheat (Triticum aestivum) followed by alfalfa (M. truncatula). The results showed that 1) the responses of AMF and M. truncatula symbiosis to soil disturbance and residue application were different. 2) The growth rate and phosphorus absorption of M. truncatula promoted by AMF were inhibited by soil disturbance, which had a negative effect on AMF. 3) The growth rate and P absorption of M. truncatula were improved by residue application. 4) AMF improved the content of SWA, and the influence of soil disturbance and residue application on SWA depended on the diameter of the soil aggregates. In conclusion, the proper application of AMF, no-till, and residue had the potential to improve soil structure, reduce water and soil loss, and increase crop yield under field conditions.