The effect of drought and intercropping on chicory nutrient uptake from below 2 m studied in a multiple tracer setup

Aims We tested if chicory acquires nutrients from soil layers down to 3.5 m depth and whether the deep nutrient uptake increases as a result of drought or intercropping with ryegrass and black medic. We also tested whether application of the trace elements Cs, Li, Rb, Sr and Se, as tracers, result in similar uptake rates. Methods The methodological tests were carried out in a pilot experiment where the tracers were applied to 1 m depth in lucerne and red beet grown in tube rhizotrons. The dynamics of deep nutrient uptake in chicory was studied in large 4 m deep rhizoboxes. A drought was induced when roots had reached around 2 m depth. Results Chicory acquired N-15 from 3.5 m depth and trace element tracers from 2.3 m depth. We found no compensatory tracer uptake with depth during drought. We found some indications of a compensatory tracer uptake from 2.3 and 2.9 m depth in intercropped chicory. Application of equimolar amounts of trace elements resulted in similar excess tracer concentrations within species. Conclusion Chicory demonstrates nutrient uptake from below 3 m but does not increase deep nutrient uptake as a response to limited topsoil nutrient availability induced by drought or intercropping.