Details

Autor(en) / Beteiligte

• Rummel, Pauline Sophie
• Well, Reinhard
• Pfeiffer, Birgit
• Dittert, Klaus
• Floßmann, Sebastian
• Pausch, Johanna

Titel

Nitrate uptake and carbon exudation – do plant roots stimulate or inhibit denitrification?

Ist Teil von

• Plant and soil, 2021-02, Vol.459 (1-2), p.217-233

Ort / Verlag

Cham: Springer International Publishing

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Background and aims Plant growth affects soil moisture, mineral N and organic C availability in soil, all of which influence denitrification. With increasing plant growth, root exudation may stimulate denitrification, while N uptake restricts nitrate availability. Methods We conducted a double labeling pot experiment with either maize ( Zea mays L.) or cup plant ( Silphium perfoliatum L.) of the same age but differing in size of their shoot and root systems. The 15 N gas flux method was applied to directly quantify N 2 O and N 2 fluxes in situ. To link denitrification with available C in the rhizosphere, 13 CO 2 pulse labeling was used to trace C translocation from shoots to roots and its release by roots into the soil. Results Plant water and N uptake were the main factors controlling daily N 2 O + N 2 fluxes, cumulative N emissions, and N 2 O production pathways. Accordingly, pool-derived N 2 O + N 2 emissions were 30–40 times higher in the treatment with highest soil NO 3 − content and highest soil moisture. CO 2 efflux from soil was positively correlated with root dry matter, but we could not detect any relationship between root-derived C and N 2 O + N 2 emissions. Conclusions Root-derived C may stimulate denitrification under small plants, while N and water uptake become the controlling factors with increasing plant and root growth.