Drought and Diversification‐Mediated Soil Legacies Influence Plant Growth and Rhizosheath Formation

While drought legacy effects are widely reported, how distinct soil biological legacies created by diversification of crops through rotation influence plant performance remains largely untested. Moreover, it remains to be investigated whether crop domestication has impacted such biological legacy effects on plant performance. Therefore, we manipulated soil origin by creating a gradient of soil‐mixing diversity (SMD) from eight cultivars for wild and domesticated barley with or without drought history. Our objective was to investigate how drought and diversification‐mediated soil legacies (created by SMD) impact the subsequent plant performance, separately for wild and domesticated barley. We found that wild barley biomass (root and shoot) increased with increasing SMD, whereas rhizosheath mass showed the opposite pattern. Also, wild barley biomass was lower in soils which experienced drought previously. These results suggest that soil legacy effects arising from crop diversification can increase resource availability to wild barley while reducing resource investment for rhizosheath formation. In contrast, domesticated barley biomass and rhizosheath mass were neither affected by drought history nor by SMD, indicating that artificial selection and breeding under high‐input and homogenous conditions have lowered the plant's sensitivity to soil histories. This research demonstrates that crop domestication has impacted not only plant traits but also the plant's sensitivity to drought and diversification‐mediated soil legacies, with implications for how plants respond to soil history and management practices.