As drought conditions persist in many regions, farmers face the challenge of managing their water resources effectively. For some, this means considering the use of surface water, such as ponds or rivers, for irrigation. Using surface water comes with its own set of risks, particularly related to produce safety.
Let's explore the implications and best practices associated with utilizing surface water during drought conditions.
Surface water sources, such as ponds, pose significant risks to produce safety due to their high quality and susceptibility to contamination from various sources, including animals and fecal matter, and are more likely to contain harmful pathogens.
Some of the potential risks associated with surface water sources include
- Livestock feces if animals have access to the water.
- Fecal contamination from birds and ducks.
- Leaching from septic tanks.
- Human recreational activities.
- Runoff from nearby fields, livestock areas, and roadways.
- The presence of dead animals.
- Dumping of waste and trash.
While surface water can be used for irrigation with caution, it should never be used for postharvest activities such as washing vegetables, handwashing, or sanitizing surfaces. For these purposes, only well or municipal water that has been tested and shown to have no detectable generic E. coli should be used.
Safe Practices for Surface Water Usage in Irrigation
If you choose to use surface water like ponds or streams for irrigation, consider the following practices to reduce potential contamination:
- Minimize Contact: Use methods like drip tape under plastic to reduce water contact with the edible parts of crops. This approach not only conserves water but also decreases the risk of disease and mildew.
- Water Testing: Regularly test surface water for bacterial contamination to establish a baseline. Surface water quality can change rapidly, so multiple tests per season are recommended.
- Crop Selection: Apply surface water to crops that are not typically consumed raw, such as potatoes, winter squash, and beets. Cooking these crops can serve as a "kill step" to reduce potential contamination.
- Die-Off Period: Allow time for a "die off" period between applying surface water and harvesting produce. Bacterial die-off rates are highly variable and depend on several factors, so relying solely on die-off is not advisable.
The Food Safety Modernization Act (FSMA) allows for a four-day period between water application and harvest when water initially exceeds standards, assuming a 0.5 log die-off per day.
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Categories: Minnesota, General