drumstick tree: an example of a plant that can do hydraulic lift

Hydraulic lift and water scarcity by Tinashe Mawodza

Many ways of improving crop yields can be discovered when scientists understand underlying processes in plants. Grantham Scholar Tinashe Mawodza introduces a process known as ‘hydraulic lift’ that could help plants in regions where water is scarce.

Hydraulic lift enables some plants to passively extract water from deeper soil horizons. They then re-deposited water into shallower soil regions bearing a lower water potential where finer roots are located. This is an important ecosystem process carried out by many deep rooted plants in areas where water is scarce.

‘Hydraulic lift: a potentially important ecosystem process’ by J. L. Horton and S. C. Hart

Tinashe Mawodza
Grantham Scholar Tinashe Mawodza.

For Journal Club we looked at Hydraulic lift: a potentially important ecosystem process. This paper highlights progress in our understanding of hydraulic lift. We discussed the potential for exploiting of hydraulic lifting plants to encourage plants to grow in deserts and arid areas.

Plants such as Prosopis tamarugo grow in the Atacama desert. And they are able to extract water from deep in the soil profile. These plants are likened to a biological ‘water pump’, able to passively access water deep underground and bring it to near the Earth’s surface. As a group, we talked about why this ecosystem process hasn’t been fully exploited across the arid world. And we conclude it may be due to the need for extensive irrigation to first establish these plants.

Could hydraulic lifters make nutrients more available?

The currently unclear role of hydraulic lifters in making nutrients more available was also considered as a beneficial role they could perform in dry areas.

Hydraulic lifters’ potential for hydrological support of other plants, such as grasses, could also support carbon dioxide sinks in these dry areas. As a result, the environmental functionality of deserts would be enhanced. Other terrestrial organisms such as soil micro-flora could also benefit from the increased soil moisture availability.

Agricultural benefits

Apart from the hydraulic lift carried out by many hardy trees and shrubs, some crops of agricultural value (e.g. Medicago sativa – alfalfa) have also been shown to hydraulically lift water to improve the efficiency of their photosynthesis. The limitation with many agricultural crops, however, is usually their shallower roots which are often not deep enough to tap into water tables at the depths of arid areas. The hydraulic lifting ability of the drought resisting drumstick tree Moringa oleifera was also discussed, as it is used extensively as a natural nutritional supplement in the developing world.

Eucalyptus: good and bad

Hydraulic lifting may also come at a cost however, as highlighted by an invasive species, Eucalyptus, native to Australia. Eucalyptus has the potential to substantially lower the water table, possibly putting wetland ecosystems at risk of eradication.

To others however, this species of trees may actually be a saving grace as its cultivation may reduce the risk of flooding where wetlands have been encroached by human settlement as a result of population growth. These rapidly growing trees may also provide an income to impoverished developing communities through the sale of the timber they produce, as well as giving governments’ carbon credits.

Our group thought the process of hydraulic lift was an interesting one with the potential to improve the arid world. But more research needs to be carried out in order to fully realise its benefits.

More on water and the Grantham Centre

If you want to find out how our work is connected to SDG 6 Clean Water and Sanitation then look here. Or you can read some of our other blogs and news about water by following the links below.

How much water does the UK use? Grantham Scholar Martin Appleby sets out the data on water use in the UK.

The Politics Of Water 1: Investigating the sustainability of rural water projects in Balaka District, Malawi. Grantham Scholar Naomi Oates writes about her fieldwork in Malawi where she is investigating rural water projects.

Grantham supervisors editors of a special issue on water use efficiency. Dr Manoj Menon and Dr Stuart Casson are editors of a special issue on water use efficiency (WUE). They both supervise Grantham Scholars, and met during their work on one of our projects.

New paper: Water pollution and advanced water treatment technologies. Grantham Scholar Manasi Mulay publishes on water pollution and treatment.

 

Edited by Claire Moran. Photo of drumstick tree by Nothing Ahead from Pexels.