Estimating the parameters of a 3-D root distribution function from root observations with the trench profile method: case study with simulated and field-observed root data

Background and Aims
Root length density (RLD) is a parameter that is difficult to measure, but crucial to
estimate water and nutrient uptake by plants. In this study a novel approach is
presented to characterize the 3-D root length distribution by supplementing data of the
3-D distribution of root intersections with data of root length density from a limited
number of soil cores.
Methods
The method was evaluated in a virtual experiment using the RootTyp model and a field
experiment with cauliflower (Brassica oleracea L. botrytis) and leek (Allium porrum, L.).
Results
The virtual experiment shows that total root length and root length distribution can be
accurately estimated using the novel approach. Implementation of the method in a field
experiment was successful for characterizing the growth of the root distribution with
time both for cauliflower and leek. In contrast with the virtual experiment, total root
length could not be estimated based upon root intersection measurements in the field.
Conclusions
The novel method of combining root intersection data with root length density data from
core samples is a powerful tool to supply root water uptake models with root system
information.