Erratum to: Biology and host specificity of Rhinusa pilosa, a recommended biological control agent of Linaria vulgaris (BioControl, 10.1007/s10526-014-9578-7)

The effects of atmospheric nitrogen (N) deposition on carbon (C) sequestration in terrestrial ecosystems are controversial. Therefore, it is important to evaluate accurately the effects of applied N levels and forms on the amount and stability of soil organic carbon (SOC) in terrestrial ecosystems. In this study, a multi-form, small-input N addition experiment was conducted at the Haibei Alpine Meadow Ecosystem Research Station from 2007 to 2011. Three N fertilizers, NH4Cl, (NH4)2SO4 and KNO3, were applied at four rates: 0, 10, 20 and 40 kg N ha-1 year-1. One hundred and eight soil samples were collected at 10-cm intervals to a depth of 30 cm in 2011. Contents and δ13C values of bulk SOC were measured, as well as three particle-size fractions: macroparticulate organic C (MacroPOC, > 250 μm), microparticulate organic C (MicroPOC, 53-250 μm) and mineral-associated organic C (MAOC, < 53 μm). The results show that 5 years of N addition changed SOC contents, δ13C values of the bulk soils and various particle-size fractions in the surface 10-cm layer, and that they were dependent on the amounts and forms of N application. Ammonium-N addition had more significant effects on SOC content than nitrate-N addition. For the entire soil profile, small additions of N increased SOC stock by 4.5% (0.43 kg C m-2), while medium and large inputs of N decreased SOC stock by 5.4% (0.52 kg C m-2) and 8.8% (0.85 kg C m-2), respectively. The critical load of N deposition appears to be about 20 kg N ha-1 year-1. The newly formed C in the small-input N treatment remained mostly in the > 250 μm soil MacroPOC, and the C lost in the medium or large N treatments was from the > 53 μm POC fraction. Five years of ammonium-N addition increased significantly the surface soil POC:MAOC ratio and increased the instability of soil organic matter (SOM). These results suggest that exogenous N input within the critical load level will benefit C sequestration in the alpine meadow soils on the Qinghai-Tibetan Plateau over the short term. © 2014 British Society of Soil Science.