Short-term N transfer from alfalfa to maize is dependent more on arbuscular mycorrhizal fungi than root exudates in N deficient soil

• Published in: Plant and soil Vol. 446; no. 1-2; pp. 23 - 41
• Main Authors: Zhang, Hualiang, Wang, Xinyu, Gao, Yingzhi, Sun, Baoru
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.01.2020; Springer; Springer Nature B.V
• Subjects: Agricultural practices; Alfalfa; Arbuscular mycorrhizas; Beans; Biomedical and Life Sciences; Corn; Crop yield; Crop yields; Cropping systems; Ecology; Exudates; Exudation; Fertilizer application; Fertilizers; field experimentation; Fungi; hyphae; Intercropping; leaves; Legumes; Leguminous plants; Life Sciences; Mimosaceae; Nitrogen; nitrogen fertilizers; Plant growth; Plant Physiology; Plant Sciences; Regular Article; Rhizosphere; Row spacing; soil; Soil Science & Conservation; Soils; total nitrogen; vesicular arbuscular mycorrhizae; China; Alfalfa/maize intercropping; Total N uptake; Root exudates; Arbuscular mycorrhizal fungi; Yield; N foliar labeling; Nitrogen transfer
• DOI: 10.1007/s11104-019-04333-1
• ISSN: 0032-079X

Aims Mycorrhizae and root exudates have been considered the two important pathways for nitrogen (N) transfer from legume to non-legume plants. The present study aimed to investigate contribution of the relative importance of arbuscular mycorrhizal fungi and root exudates in short-term N transfer. Methods A field experiment was conducted to explore N transfer from alfalfa to maize under two different N application levels using 15 N leaf labeling. Results N transfer amount ranged from 7 to 10 mg N plant −1 from alfalfa to maize and significantly decreased (by 11%–22%) with N fertilizer application. Intercropping of 4 rows of maize and 6 rows of alfalfa with 30 cm intra-row spacing (IMA43) was the optimal intercropping mode, which increased N transfer, total N uptake and yield by 18%, 15% and 11%, respectively. The relative importance of arbuscular mycorrhizal fungi and root exudates on N transfer was dependent on soil N availability. Under no N addition, hyphal length density (HLD) of rhizosphere soil explained the largest significant amount (50%) of the variability in N transfer and crop yield. However, root exudates explained 77% of the variability in N transfer and crop yields with N fertilizer application. Conclusions Our findings highlighted that N transfer is reliant more on arbuscular mycorrhizal fungi than root exudates in N-deficient soil, whereas root exudates play a more important role in N-fertilized soil.