Effect of elevated CO2 and N fertilisation on soil nematode abundance and diversity in a wheat field

An experimental platform of free-air CO2 enrichment (FACE) was established in mid June of 2004 over a rice-wheat rotation ecosystem located at a suburb of Jiangdu, China. We compared the abundance and diversity of soil nematodes from a wheat field with high (225.0 kg N ha(-1)) and low (112.5 kg N -ha(-1)) levels of N fertilisation exposed to the elevated and ambient CO2 during the wheat growing season in 2005. The results showed that elevated CO2 and N fertilisation had significant effects on the abundance and diversity of soil nematodes. Elevated CO2 increased the abundance of omnivores-predators, the values of maturity index (MI) and structural index (SI) of nematode assemblage at the jointing stage of wheat. Two levels of N fertilisation had significant effects on the abundance of fungivores at the wheatjointing stage, while nematode channel ratio (NCR) showed responses to different N fertilisation and the interaction effects of elevated CO2 and N fertilisation at the wheat ripening stage. (c) 2006 Elsevier B.V. All rights reserved.