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Inorganic N addition replaces N supplied to switchgrass ( Panicum virgatum ) by arbuscular mycorrhizal fungi
Author(s) -
JachSmith Laura C.,
Jackson Randall D.
Publication year - 2020
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1002/eap.2047
Subject(s) - panicum virgatum , perennial plant , biomass (ecology) , agronomy , bioenergy , agroecosystem , nutrient , biology , miscanthus , biofuel , ecology , agriculture
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.