Farm Table says:
Hydraulic Redistribution by Native Sahelian Shrubs: Bio irrigation to Resist In-Season Drought
What is the problem?
In some drought stressed areas, vulnerable crops be assisted by hydraulic redistribution caused by associations with selected woody shrub species.
As an example, African Sahel region farmer observations found that pearl millet yields (Pennisetum glaucum) were greatly benefited during seasons of drought when grown in the same fields as the native woody shrub, Guiera senegalensis J.F. gmel.
Researchers from the US and Senegal investigated if hydraulic redistribution mechanisms were involved in crop benefits and suggested that similar mechanisms may be applied to other major crop species, such as wheat or tomato, to alleviate drought stress.
What did the research involve?
In a farming system with a yearly rotation of Pennisetum glaucum (pearl millet) and Arachis hypogea (groundnut) crops grown in fields with a density of 240 senegalensis shrubs per hectare the researchers tested whether the shrubs performing hydraulic redistribution were benefitting the pearl millet crops by applying and monitoring water enriched with deuterium (which was measured) to the deep-rooted G. senegalensis shrubs.
What were the key findings?
- Millet biomass production was over 900% greater when intercropped with shrubs than crops grown without shrubs present.
- Evidence of the deuterium tracer was detected in aboveground stems of intercropped millet within 12–96 h of tracer introduction.
- The only viable path for the deuterium enriched H2O into millet was via hydraulic redistribution by the shrubs.
- This finding describes evidence that hydraulic redistribution and water transfer is an important mechanism in drought stress resistance and successful agroforestry systems in regions where food security is a serious issue.
This paper was summarised by Luke Stafford (Bachelor of Biological Sciences with Honours – Botany and Genetics Majors (La Trobe University) and reviewed by Nickala Best (PhD Student (La Trobe University). Learn more about Luke and Nickala here.