This article appears in the following Journal of Experimental Botany issue: Special Issue: Crop Science for a Changing Climate and Plant Biomass for Food and Energy [View the issue table of contents]
REVIEW-ARTICLE |
Physical effects of soil drying on roots and crop growth
1Cross Institute Programme for Sustainable Soil Function (SoilCIP), Centre for Soils and Ecosystem Function, Department of Soil Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
2Centre for Bioenergy and Climate Change, Department of Soil Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
* To whom correspondence should be addressed: E-mail: andy.whitmore{at}bbsrc.ac.uk
The nature and effect of the stresses on root growth in crops subject to drying is reviewed. Drought is a complex stress, impacting on plant growth in a number of interacting ways. In response, there are a number of ways in which the growing plant is able to adapt to or alleviate these stresses. It is suggested that the most significant opportunity for progress in overcoming drought stress and increasing crop yields is to understand and exploit the conditions in soil by which plant roots are able to maximize their use of resources. This may not be straightforward, with multiple stresses, sometimes competing functions of roots, and conditions which impact upon roots very differently depending upon what soil, what depth or what stage of growth the root is at. Several processes and the interaction between these processes in soil have been neglected. It is our view that drought is not a single, simple stress and that agronomic practice which seeks to adapt to climate change must take account of the multiple facets of both the stress induced by insufficient water as well as other interacting stresses such as heat, disease, soil strength, low nutrient status, and even hypoxia. The potential for adaptation is probably large, however. The possible changes in stress as a result of the climate change expected under UK conditions are assessed and it appears possible that wet warm winters will impact on root growth as much if not more than dry warm summers.
Key words: Crop, drought, hypoxia, mechanical impedance, physical stress, root, root environment, root growth, soil, water-logging
Received 6 March 2009; Revised 20 May 2009 Accepted 27 May 2009