From W.R. Gardner to the present day: How research on water (un)availability to plants sometimes hindered its own progress

The importance of water and its limitations for the functioning of plants and terrestrial ecosystems have long been studied. However, science sometimes hinders its own progress by the negligence of significant findings from earlier periods.

One example is the pioneering work of W.R. Gardner (1960+), who made significant contributions to our current knowledge on limitations to plant water use. Gardner’s early work focused on the dynamic (un)availability of soil water at the small scale, which is caused by the distinct decrease in soil hydraulic conductivity around the water-absorbing roots during transpiration.

Since then, however, this soil-specific dynamic limitation through soil hydraulic conductivity has often been neglected. While this is well justified at times, for example when focusing on seasonal rather than daily drought conditions, we argue that these Gardner-like limitations to plant water use at the small scale should not be ignored, even if observations are made at much larger scales (e.g. using Eddy-Covariance or remote sensing) than where plant roots take up water.

This is particularly relevant as drought research has become more interdisciplinary. While originally a challenge for agriculture-related soil physics (e.g., W.R. Gardner and D. Hillel), plant and ecosystem water limitations have increasingly been addressed by other disciplines, such as plant hydraulics and climate science, at larger scales. Our recent work reinforces the idea that small-scale soil hydraulic conductivity limitations can be important at larger scales in a soil- and plant-specific manner.

We believe that the field of water limitation research exemplifies not only the pitfalls of generating scientific knowledge, but above all the great potential of interdisciplinary research initiatives.