Complete: Understanding water uptake in sugar beet

Timescale: 2015 - 2019

Project Lead: Tamara Fitters PhD student

Project Sponsor: University of Nottingham and BBRO

Project Summary

It has been long known that sugar beet does not yield well under drought conditions. In the UK there is a 10% yield loss as a result of drought on average and in dry years this can increase to up to 25% yield loss (Jaggard et al. 1998). UK sugar beet is grown predominantly in East Anglia, on sandy loam soils, where annual rainfall is relatively low (>700 mm). This means there is low water availability during most of the growing season, and during the summer period drought often occurs (Brown and Biscoe 1985). One way for plants to mitigate drought is by growing deep roots to reach water stored in deeper soil layers. Sugar beet are able to grow roots that exceed 1 m depth, however it seems that 80% of the water is taken up from the top 30 cm of the soil (Brereton et al. 1986). Possible reasons for the lack of water uptake from depth could be root physical restraints such as compaction. Roots tend to clump together into already existing pores when soil compaction is present. This would limit water uptake from those compacted layers, despite roots being able to reach those layers (Brown and Biscoe 1985). Another reason for the limited water uptake could be root physiological restraints such as immature root tissue (Varney and Canny 1993).

Main Objectives

This project has focussed on root growth and water uptake from the soil to find ways to mitigate yield losses as a result of drought. Our aim was to identify limitation to water uptake. We started small in a glasshouse setting to assess root growth under varying watering regimes. After this we scaled up to large boxes in a polytunnel as well as field experiments. Our main questions were:

Do sugar beet grow deep roots?
- Do they take up water with those deep roots?
- Are there any root physiological restraints?
How does drought affect root growth?
- Does the timing of the drought change the plant response?
Are there any varietal differences in root growth?

Latest Report

Final report

Tamara Fitters successfully completed her PhD. Her thesis is available from the BBRO

Outcomes / Key Message For Growers And Industry

Overall, we found that sugar beet are capable of growing deep roots and water uptake from depth happens. However, there are some limitations to water uptake from depth such as immature root tissue and compaction resulting in root clumping. When drought occurs plants proliferate their roots more at depth. It also seems that plants recover more quickly from early drought than late drought. Our field experiments showed that there are varietal differences. This has also been noticed by one of the sugar beet breeders who have showed interest in the root research and the findings about the immature root tissue. They are funding a follow up project to look at the maturity of the root tissue and its effect on water uptake. All in all the project has given us a better insight into water uptake in sugar beet and it has given us more opportunities to look for improvement in the future.