Hyphosphere regulation of earthworms and arbuscular mycorrhizal fungus on soil N and P availability

摘要

Earthworms and arbuscular mycorrhizal (AM) fungi are important ecosystem engineers that co-occur in soil and belong to different guilds. In this study, hyphosphere interactions between earthworms and AM fungi on soil nitrogen (N) and phosphorus (P) availability were investigated under field conditions with a modified chamber near the maize root. The experimental design consisted of root exclusion chambers that either allowed (30m pores) or precluded (0.45m pores) growth of AMF hyphae (AM factor), with or without earthworm addition (earthworm factor). Hyphal length density, soil content, soil available P concentration, urease and alkaline phosphatase activities were tested at maize VT (tassel), R1 (silking), R2 (blister), R3 (milk) and R4 (dough) stage. Results showed that earthworms did not impact hyphal length density in the hyphosphere. AM and AM+E treatments caused a decrease in available phosphorus, while the E treatment increased content during the whole experiment period. AM and AM+E treatments could significantly increase soil alkaline phosphatase activities compared to non-AMF treatments, while E and AM+E treatment could significantly increase soil urease activities compared to non-Earthworm treatments. Hyphosphere regulation of earthworms and arbuscular mycorrhizal fungus on soil N and P availability might lead to greater nutrient uptake by plant. These interactions are important for utilization of soil biological fertilization in sustainable agro-ecosystems.