Correction to: Changes in the characteristics of soil dissolved organic matter over time since inter-planting with white clover ( Trifolium repens L.) in apple orchards on the Loess Plateau in China

Purpose Dissolved organic matter (DOM) plays a key role in agroecosystems’ carbon cycling. However, the DOM evolutionary signatures and the timing of equilibrium being achieved in dryland inter-planting systems remain unclear. This study aimed to determine the characteristics of DOM dynamics using a three-dimensional fluorescence excitation-emission matrix combined with parallel factor analysis (EEMs-PARAFAC). Methods DOM contents, different related components accumulation were assessed using clear tillage (CT) as the control, white clover ( Trifolium repens L.) of three different ages (4, 8, 12 years), representing a chronosequence, in apple orchards on the Loess Plateau. Results At a depth of 0–10 cm, DOM concentration decreased with depth and significantly increased with longer inter-planting, and the five fluorescence components contents of soil DOM showed a similar trend. Moreover, the relative abundances of humic-like (C2, C3) was higher than CT, but the protein-like was lower. The ultraviolet–visible spectral and optical indices indicated that DOM mainly originated from mixed sources, and gradually tended towards greater DOM molecular complexity with increasing time since sowing. Microbial biomass nitrogen and soil organic carbon (SOC) were the most important two factors affecting DOM over time, contributing to 87% and 77% of the total variation. Conclusions This study demonstrated that inter-planting time and soil depth played important roles in determining DOM content and component accumulation. Overall, inter-planting with white clover in orchards can effectively improve the accumulation of macro-molecular humic-like DOM, which probably promotes SOC storage. Long-term experiments are required exploring DOM dynamics and the timing of equilibrium being reached.