10 years of monitoring recycled water: what we have learned

Water,

Adoption of recycled water is an important tool in water conservation, and there continues to be greater use of this resource with every year that goes by. That said, there are some management challenges posed by the use of recycled water. None are insurmountable, but being prepared and aware will help you to use recycled water as effectively as possible.

Starting in 1999, we had a great opportunity to initiate a long-term study on the effects of recycled water on turf health and management. Thanks to PACE Turf member Jeff Beardsley of Big Canyon Country Club, we were able to study changes in soil chemistry in 14 fairways that were irrigated with recycled water, and 4 fairways that were irrigated with domestic water. The results of this study were covered in a poster presentation that we made at Crop Science Society of America meetings. You can view and print the poster here, though it is a fairly large (528 KB) pdf document. Some of the key points from the study include:

• Significant increases in soil salinity, nitrogen and organic matter were the most important trends observed in areas irrigated with recycled water.
• To reverse these trends, these management practices were instituted:
1. Periodic leaching to limit soil salts to less than 6 dS/m
2. Switch to higher quality domestic water during the summer months to mitigate build-up of salts and nitrogen
3. Aerification and sand topdressing to dilute organic matter and to allow increased leaching without loss of soil integrity
4. Re-surfacing of fairways to remove excess organic matter
5. Decreased rates of nitrogen fertilizer to accommodate the high levels of N delivered in irrigation water
• Although the focus is frequently on the quality of the recycled water, it turns out that soil chemistry, soil physical characteristics and rainfall patterns were equally important in the successful use of recycled water on golf courses.
• A contract with the water provider should define water quality limits and delivery guarantees, and should cover the cost of management programs (cultivation, amendments, monitoring programs) adopted to prevent soil and plant damage from long-term use of recycled water.