Facilities and Methods for Simultaneous Studies of Deep Root Growth and Function

Deep rooting play important roles in plant and ecosystem function in natural plant communities, and is important for agricultural productivity and sustainability. Studies have illustrated the potential of working with crop species, crop management and plant breeding for the increase of deep root activity in crop production.

Understanding of deep rooting is limited by the obstacles of studying fine roots deep in the soil. To strengthen our understanding of deep rooting, its occurrence and its contribution to plant systems, new methods are needed allowing frequent and detailed studies, of root growth and activity.

For this purpose, we have recently built three facilities, and we now have the first results illustrating their potential for deep root research:

24 rhizotrons, 4m high with transparent sides and with direct access to the soil, allowing combined studies of root growth and root function, e.g. by isotope tracer labelling and soil water sensors.

24 open field plots, each equipped with 6 minirhizotrons and 6 access tubes, all to 5m soil depth. The access tubes allow direct access to the soil at different depths, e.g. by using an ingrowth core technique. Half the plots are equipped with soil water sensors at four depths to 2.5m. By this, we try to establish similar opportunities in the field as we have in the “Root towers”.

Facility for deep root phenotyping: A facility built with 600 minirhizotrons allowing root observation to 1.8 or 2.8m depth. Each plant genotype is grown in a row along a minirhizotron and at the same time subjected to a water stress gradient created by a subsurface irrigation system and rainout shelters. The water gradient should allow aboveground phenotyping for deep rooting, e.g. using drone based thermal imaging, to combine with the root data from the minirhizotrons.