Earthworm-induced N2O emissions in a sandy soil with surface-applied crop residues

Giannopoulos, George, van Groenigen, Jan Willem and Pulleman, Mirjam M. (2011) Earthworm-induced N2O emissions in a sandy soil with surface-applied crop residues. In: 9th International Symposium on Earthworm Ecology, 2010-09-05 - 2010-09-10, Veracruz.

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Abstract

Earlier research with endogeic and epigeic earthworm species in loamy arable soil has shown that both earthworm groups can increase nitrous oxide (N2O) emissions, provided that crop residue placement matches the feeding strategy of the earthworm ecological group(s). However, it is not yet clear whether these effects also occur in sandy soils which typically contain less soil organic matter and have low soil aggregation levels. Here, we aimed to quantify N2O emissions as affected by endogeic and/or epigeic earthworm species, and to relate changes in N2O emissions to earthworm-induced changes in soil properties in a sandy soil. A 90 day mesocosm study was conducted with sandy soil and 15N-labeled radish (Raphanus sativus cv. Adagio L.) residue applied on top. Treatments included: (i) no earthworm addition, (ii) addition of the endogeic species Aporrectodea caliginosa (Savigny), (iii) addition of the epigeic species Lumbricus rubellus (Hoffmeister), and (iv) both species combined. An additional treatment was included without earthworms and with residue manually incorporated into the soil. L. rubellus significantly increased cumulative N2O emissions from 228 to 859 μg N2O–N kg−1 (F1,12 = 83.12, P < 0.001), whereas A. caliginosa did not affect N2O emissions. In contrast to earlier studies in loamy soil, no positive interaction between both species with regard to N2O emissions was found. This was probably related to high competition for organic resources in the relatively poor soil and a low potential for stable soil aggregate formation (and associated anaerobic microsites) by endogeic worms in sandy soil. 15N isotope analysis revealed that the activity of L. rubellus significantly increased (F1,12 = 6.20, P = 0.028) the recovery of 15N in the 250–8000 μm size fraction, indicating incorporation of crop residues into the mineral soil. When residues were manually incorporated, N2O emissions were significantly (P < 0.008) lower (509 μg N2O–N kg−1) than when incorporated by L. rubellus. The high N2O emissions in the presence of L. rubellus, when compared to manual mixing, suggest a stimulation of microbial activity and/or changes in the microbial community composition. Insights on the earthworm effects on N2O emission from such soils are discussed.

Item Type:	Conference or Workshop Item (Paper)
Uncontrolled Keywords:	earthworms,endogeic,epigeic,nitrous oxide,n-15,soil organic matter turnover
Faculty \ School:	Faculty of Science > School of Biological Sciences Faculty of Science
Depositing User:	Pure Connector
Date Deposited:	16 Jan 2015 16:04
Last Modified:	20 Oct 2022 23:41
URI:	https://ueaeprints.uea.ac.uk/id/eprint/51250
DOI:	10.1016/j.pedobi.2011.09.005

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