Effective rooting depth of mustard under dryland conditions
de Jong, E.
We conducted a field study to investigate the effective rooting depth of mustard (Brassicajuncea L. Coss.). The data on effective depth of root water extraction and root distribution are needed in understanding and modelling root-soil-water interactions and to use in soil water balance estimations. Data was collected from upper and lower slope positions in a mustard field. Soil water content was determined using neutron moderation (10- to 120-cm profile). Soil water content- time curves were used to identify the effective depths of root water depletion ("effective rooting depth"). Root distribution and the maximum rooting depth were measured with the trench profile method. For both slope positions maximum water depletion depths were deeper than the actual rooting depth at the early growth stage. This may be due to the upward water migration. Maximum rooting depth for mustard reached up to 150 cm at upper slope position but the effective rooting depth was found around 120 cm. This may be due to low rooting density at the bottom of the root zone at upper slope. At the lower slope, water depletion depth reached 100 em only for a short duration and was usually around 60-80 cm.
Soils and Crops Workshop