Inorganic N addition replaces N supplied to switchgrass (Panicum virgatum) by arbuscular mycorrhizal fungi. Issue 2 (10th January 2020)

• Record Type: Journal Article
• Authors: Jach‐Smith, Laura C.; Jackson, Randall D.
• Is Part Of: Ecological applications. Volume 30:Issue 2(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-10
• Subjects: 15N -- AMF -- bioenergy crops -- extra‐radical mycelium -- grasslands -- isotopic abundance -- nitrogen supply -- nitrogen transfer -- perennial grasses; Ecology -- Periodicals; Environmental protection -- Periodicals; Biology, Economic -- Periodicals; 577.05
• DOI: 10.1002/eap.2047
• Languages: English
• ISSNs: 1051-0761

Abstract

Abstract: Arbuscular mycorrhizal fungi (AMF) provide many benefits in agroecosystems including improved soil tilth, carbon sequestration, and water and nutrient transfer to plants. AMF are known to affect plant nitrogen (N) dynamics and transfer N to plants, but there have been few studies addressing whether the amount of N transferred to plants by AMF is agronomically relevant. We used δ 15 N natural abundance methods and δ 15 N mass balance equations to estimate the amount of plant N derived from AMF transfer in perennial grasses managed for bioenergy production under different N addition treatments (0, 56, and 196 kg N/ha). Differentiation of δ 15 N among plant, soil N, and AMF pools was higher than anticipated leading to calculations of 34–55% of plant N transferred by AMF in the treatments receiving no N addition to 6–22% of plant N transferred to plants in high‐N addition treatments. AMF extra‐radical hyphae biomass was significantly reduced in the high‐N (196 kg N/ha) addition treatments, which was negatively correlated to enriched plant δ 15 N. Our results suggest that N addition decreases AMF N transfer to plants. When N was limiting to plant growth, AMF supplied agronomically significant amounts of plant N, and a higher proportion of overall plant N. Because differentiation between N pools was greater than expected, stable isotope measurements can be used to estimate N transfer to AMF plant hosts.