Depending where you are, this year many Small farms in Canada faced moderate to severe droughts, causing water table drops and stressed wells. To address these issues, some farmers consider using surface water sources like ponds or rivers for irrigation. Before you do that it is crucial to understand the risks and implement best practices for crop safety.
Surface Water Risks:
Surface water, like ponds, can be a high-risk water source due to its variable quality and susceptibility to contamination. Pathogenic bacteria like E. coli and Salmonella are more likely to be present in surface water compared to well water sources.
Risks include livestock feces, bird and duck feces, leaking septic tanks, human recreation near water, runoff from nearby fields, livestock, and roadways, dead animals, dumping and trash, which can all contribute to contamination of the water source.
Surface water should be used cautiously for irrigation but not for postharvest tasks like washing vegetables, hands, or sanitizing surfaces. Instead, use well or municipal water tested for no detectable E. coli.
Best Practices for Safe Surface Water Irrigation:
- Reduce Water Contact: Reduce water contact with edible parts of crops, such as using drip tape under plastic, which conserves water and reduces the risk of plant disease.
- Regular Water Testing: Frequently conduct bacterial contamination tests on surface water to establish a baseline, recognizing that contamination levels can undergo rapid fluctuations.
- Smart Crop Selection: Opt for using surface water on crops that are not usually consumed raw, such as potatoes, winter squash, and beets. Cooking serves as an effective "kill step" to eliminate potential contaminants.
- Bacterial Die-Off Timing: Incorporate a waiting period between water application and harvest to promote bacterial die-off. The duration of this interval varies depending on several influencing factors.
- Regulation Compliance: Comply with the Canada Food Inspection Agency guidelines, allowing a 4-day interval from water application to harvest if initial water standards are not met.
Small farms can effectively use surface water for irrigation, ensuring product safety through regular testing, careful planning, and adherence to guidelines, even in challenging conditions.