Arango, Jacobo

Arévalo, Ashly

Benito, Marta

Pulleman, Mirjam M.

Teutscherova, Nikola

Vásquez, Eduardo

CGSpace

Tropentag, September 17-19, 2018, Ghent“Global food security and food safety:The role of universities”Arbuscular Mycorrhizal Fungi Increase the Abundance ofAmmonia-Oxidising Bacteria, but Suppress N2O Emissions afterFertilisationNikola Teutscherová1, Eduardo Vazquez1, Jacobo Arango2, Ashly Arevalo2, MartaBenito1, Mirjam Pulleman31Technical University of Madrid, Dept. of Agricultural Production, Spain2International Center for Tropical Agriculture (CIAT), Colombia3Wageningen University and Research, The NetherlandsAbstractThe potential of the symbiosis between plants and arbuscular mycorrhizal fungi (AMF) to re-duce greenhouse gas emissions from soil is gaining scientific attention in the last years. Given therelatively high nitrogen (N) requirements of the AMF and their generally positive effect on hostplant growth, AMF may reduce the availability of mineral N that would otherwise be subject tonitrification, which is associated with N2O emissions. We investigated the impact of AMF on thegrowth of tropical grass Brachiaria decumbens Stapf. and N2O released after urea application. Todetect the role of nitrification in N2O emissions we used the nitrification inhibitor dicyandiamide(DCD). A mesocosm study (106 days) with two AMF treatments (with and without AMF) andthree fertilisation treatments (control, urea and urea+DCD) was set up and plant growth, soil pro-perties and N2O emissions were measured for two weeks after fertiliser application. Without DCD,the production of N2O was significantly increased by urea, suggesting that inhibition of nitrificationcan mitigate N2O emissions. The cumulative emissions of N2O after urea application were reducedby 46% in the presence of AMF when compared to non-AMF pots. Nevertheless, the abundanceof ammonia-oxidising bacteria (AOB) was increased by urea and AMF, while plant growth was re-duced by the AMF presence. The increased root:shoot ratio of the biomass in AMF- pots suggestscompetition for N between AMF and plants. In this study, we demonstrated that immobilisationof N by AMF may significantly reduce N2O emissions, at least in the short-term, even when plantgrowth is reduced. Furthermore, the inverse relationship found between (higher) AOB abundanceand (lower) nitrification rates suggests that changes in the activity of AOB, rather than abundance,may be indicative of the impact of the mycorrhizal symbiosis on N cycling in tropical grasslands.Alternatively, the difference between N2O emissions from AMF and non-AMF pots may (partly) beexplained by increased reduction of N2O in the presence of AMF. Longer-term studies are neededto verify whether the observed effects of AMF on N2O emissions and/or plant growth persist orare limited to initial immobilisation of N by AMF in N-limited systems.Keywords: Arbuscular mycorrhizal fungi, Brachiaria, N2O emissions, nitrification, ureaContact Address: Nikola Teutscherová, Technical University of Madrid, School of Agricultural, Food and BiosystemsEngineering, Dept. of Agricultural Production, Av. Puerta de Hierro, 2, 28040 Madrid, Spain, e-mail: n.teutscherova@gmail.com

Arbuscular mycorrhizal fungi increase the abundance of ammonia-oxidizing bacteria, but suppress N2O emissions after fertilization

https://cgspace.cgiar.org/bitstream/10568/97774/1/Arbuscular%20mycorrhizal%20fungi%20increase%20the%20abundance%20of%20ammonia-oxidizing%20bacteria%2c%20but%20suppress%20N2O%20emissions%20after%20fertilization.pdf

Arbuscular mycorrhizal fungi increase the abundance of ammonia-oxidizing bacteria, but suppress N2O emissions after fertilization

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