Manitoba Agriculture, Food and Rural Initiatives
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NEWS RELEASE
Innovative Idea: Efficient Irrigation
University of Manitoba researchers are exploring a simple, inexpensive, water-saving system for Manitoba greenhouses.
The capillary irrigation system allows plants to seek out their own water from a constantly available water source. In this system, a semi-permeable membrane separates the plant in its potting soil from its own water supply. When plant roots generate enough negative pressure against the membrane, water is drawn through the membrane.
Dr. Ranjan Sri Ranjan with the Department of Biosystems Engineering explains that negative pressure is what allows plants in your house or garden to move water into their roots from the surrounding soil. In Sri Ranjan's experimental greenhouse, the water is drawn through porous material into the root zone due to the negative pressure generated by the roots within the root zone.
“There are several benefits to the capillary irrigation system,” says Sri Ranjan. “Since irrigation is entirely controlled by the plant itself, the risk of wasting water through evaporation or runoff is lowered.”
Even skilled greenhouse operators with drip irrigation systems can save water with this system. That's because traditional drip irrigation systems send a predetermined amount of water to the soil even when the water needs of adjacent plants are different.
Sri Ranjan has found that hot peppers grow well using the capillary-irrigation system. The continuous water supply in the system eliminated the need for larger soil depth to store water, meaning that greenhouse operators can free up valuable greenhouse space, potentially without any loss of yield.
Sri Ranjan's research is expected to lead to the development of low-cost, self-watering greenhouse production systems suitable for use by remote northern communities. ARDI and Manitoba Hydro are funding partners in this project. ARDI is funded by Growing Forward, a federal-provincial-territorial initiative.
To read more on this project click on Project Number 05-651
Photo: Vanathy Nalliah with lettuce growing in the capillary irrigation system.
