The development of models describing water and nutrient fluxes to and through 3D spatially resolved root structures in soils brings along the need to predict or describe the root architecture and root growth in detail. However, detailed data to calibrate and validate such architecture and growth models is typically not available. Here, we investigate the sensitivity of the root architecture model RootTyp to changes in its model parameters and reconstructed the root system architecture of barley growing in an undisturbed lysimeter using minirhizotron images at four different depths. Root arrival curves from a series of minirhizotron images were used to calibrate RootTyp using a range of realistic architectures. Our results show that minirhizotron data do not contain enough informationto warrant identification of the parameters governing these processes, as the additional parameters act similarly on data characteristics as the initial ones. Therefore, different experimental techniques should be combined to constrain the model parameters better in the future.