July 2000 (2 of 2)

Planning for a Water Emergency

So far, the year 2000 has been a very dry one, with many golf courses receiving less than 2 inches of rainfall. Golf courses which have their own wells or lakes fed by runoff or springs, are the first to experience an absolute shortage in available water (regardless of cost). Shortages may also occur from cutbacks from municipal water providers, and perhaps even from discontinuous supplies of effluent.

This article deals with drought, from the standpoint of turfgrass survival and management, should water cutbacks occur due to lack of otherwise normally available water. Practices listed below range from temporary shortages, to long-term reductions until restrictions are lifted, or to complete shut down.

Preparing for Drought:

If you know that water use restrictions are eminent, you can do the following to heat/drought harden the turf.

1. Increase irrigation intervals, if possible. Apply the same amount of water, but increase time intervals between applications. This will increase rooting depth and the mild stress that occurs will harden the plants for heat/drought tolerance. This works best on areas that have soils 6-8 inches deep. It won't work for shallow soils that have a hardpan layer, Dg, or caliche layer close to the surface.

2. Replace standard application of - N - , with iron. Iron will make the turf green, without the growth push of nitrogen. High - N - content in plants decreases heat and drought tolerance.

3. Apply K fertilizer 2 weeks before irrigation cut backs.

4. Raise mowing heights on roughs, fairways, and tees. Turfs will store more food reserves, have better insulation properties, somewhat better traffic tolerance, and better regrowth after the "drought" conditions ceases.

5. Deep tine aerify roughs, fairways and tees 3 weeks before water use restrictions. Bermuda roots will follow these holes and so will new rhizomes.

During Drought/Water Restriction Period(s)

Depending on the length of the drought (temporary or season-long) there must be a decision on what areas will have restricted play expectations. If restrictions are severe, consider not irrigating roughs, fairways, tees and greens in that order.

If restrictions are calculated as some percentage of a normal or typical water allotment, then you have more options (below).

6. Deficit irrigate, by applying either less amounts of water at each irrigation event, or apply standard amounts, but skip one irrigation per week. The latter is easier on the turf in the long run. It is very easy to do either of these if you have a PC computer as the main controller.

If you only have field satellite control, it is easier to skip one irrigation event than to change run times (deficit irrigation by rate).

If you have the PC as the controller, you can lower the Kc (crop coefficient value) to get the same effect (deficit by rate), or remove one "irrigation day" from the 14-day schedule (deficit by timing).

If you do both (decrease irrigation rate and skip days) the turf will not last as long, before going dormant. Also, if the water is salty, practice deficit irrigation by timing, only!

Courses with large roughs can trade-off irrigation for keeping fairways watered much easier than desert courses with limited roughs.

Control Cart Traffic:

Nothing will injure under-irrigated turf more so than traffic! Practice one of the agreed upon options:

7. No carts

8. Carts stay on paths only

9. Carts stay on outside of rough

10. Carts travel on roughs only

In prolonged drought, even the 90-degree rule will severely injure the grass on heavily played courses.

Daily Maintenance Routines:

Don't mow, just for the sake of mowing (if turf is barely growing). Rather, have the crew perform irrigation catch-can tests, one fairway at a time. What better time to get accurate precipitation rates and calculate run-time modifiers based on field performance.

Continue hand-watering greens between standard-normal irrigations.

11. Under the worst and most severe conditions, to maintain bentgrass, it takes about 28,000 gallons of
water to maintain 18,000 square feet of bentgrass greens. This will be the minimum allocation to keep the greens if the course was to be shut down. If there is a regular source of water to irrigate greens, take them out of play and raise the greens to 3/16 or ¼ inches to insulate crowns and promote heat tolerance.

12. On 18 hole courses, only 9 holes could be made available for play.

13. On large-acreage 18 hole courses, with only full circle heads, the roughs could be shut off (heads capped). In this case, the outer edges of turf will appear scalloped with green and straw colored turf.

14. In the worse case scenario (no water), long-term shut down is inevitable. The renovation costs of re-establishment are greater than loss of revenue.

15. The turf will need a good six weeks regrowth before overseeding, otherwise, don't overseed.

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