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

ABSTRACT

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 (30 μm pores) or precluded (0.45 μm pores) growth of AMF hyphae (AM factor), with or without earthworm addition (earthworm factor). Hyphal length density, soil and 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 and 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.

KEYWORDS:

• Hyphal length density
• soil alkaline phosphatase
• soil nutrient availability
• soil urease maize

Acknowledgments

We are grateful to Dr. Stavros D. Veresoglou for valuable comments on an earlier version of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Huan Li, Ph.D., is a researcher at College of Resources and Environment, Qingdao Agricultural University, Qingdao, China. He published articles on Biology and Fertility of Soils and Acta Agriculturae Scandinavica Section B - Plant Soil Science, focusing on plant nutrition, soil biological fertility and Mycorrhiza-earthworm interaction.

Dan Xiang, Ph.D., is a researcher at College of Resources and Environment, Qingdao Agricultural University, Qingdao, China. She published articles on New Phytologist, Acta Agriculturae Scandinavica Section B - Plant Soil Science, and Microbial Ecology, focusing on microbial molecular ecology and microbial biogeography.

Chong Wang, Ph.D., is a researcher at College of Resources and Environment, China Agricultural University, Beijing, China. He published articles on Biology and Fertility of Soils, Pedobiologia, Microbial Pathogenesis and European Journal of Soil Biology, focusing on plant nutrition, soil biology and soil health and earthworm ecology.

Additional information

Funding

The research was funded by the National Natural Science Foundation of China [grant number 31570514], and [grant number 31301854].