Although windbreak hedges promote particulate organic matter addition, they do not support additional key soil functions in neighboring crop fields, <i>D'Hervilly et al.</i>

Windbreak hedges represent one of the most frequent form of agroforestry in the Czech Republic. Windbreaks hedges could benefit neighboring fields by providing additional organic matter in the form of leaf litter and habitats for soil organisms that could disperse into the field. We investigated the effect of the presence of poplar windbreak hedges versus simple grass margins at the field boundary on a wide set of soil properties in south Moravia. We found that, although windbreak hedges promote soil particulate organic matter addition in the field, they do not affect the stable mineral-associated soil organic carbon. The presence of windbreak hedges at the margin did not affect either most indicators of soil biological fertility (microbial biomass and community composition, macrofauna and mesofauna abundance) or the content in available nutrients in the field. A similar “edge effect” was detected for microbial biomass and soil organic carbon in the presence of both windbreak hedges and grass margins, with decreasing values when increasing the distance from the field boundary. Interestingly, the grass margins hosted a higher abundance of macrofauna and nematodes than the windbreak hedges. These results emphasize that intensive intra-plot practices, such as tillage and fertilization, might have a stronger effect on decomposition, soil organism diversity and carbon stabilization than the addition of trees at the boundary, what may hinder any potential benefit of agroforestry. It also confirms the importance to maintain a wide diversity of non-cropped elements to maintain soil biodiversity, including grass margins and not only woody ones.