Yield‐Dependent Allocation Functions Overestimate Root‐Derived Carbon Inputs in Wheat and Maize

ABSTRACT Root‐derived carbon (C) inputs for wheat and maize were estimated using the yield‐based allocation functions of Bolinder et al. and Jacobs et al. Comparison with measured root C showed systematic overestimation that becomes larger as predicted C increases. Bolinder gave mean absolute errors (MAE) of 0.4 Mg C ha −1 (wheat) and 1.0 Mg C ha −1 (maize), Jacobs produced larger errors. These results indicate that static, yield‐dependent functions inadequately capture root‐derived C inputs, highlighting the need for dynamic, environment‐specific approaches.