1. The Effects of Drought on Pecan Quality Lenny Wells University of Georgia

3. “If there is magic on this planet, it is contained in water.” ---Loren Eiseley

4. 4

7. http://groundwaterwatch.usgs.gov

8. Pecan Water Use Pecans extract most of their water from the upper 32 inches of the soil profile Need 60” of water per year – In the SE, rainfall can account for 50-67% of needs Pecan trees can use as much as 350 gal/day Greatest demand is during August/September Pecan Irrigation systems are designed to be supplemental to rainfall At 12 trees per acre, Drip/Microjet system capacity should be 3600-4200 gallons/acre/day

9. How Do Pecan Trees Use Water?

10. What happens to pecans when drought occurs:

11. Fruit-drop Pattern I IIIIIIV MayJuneJulyAug.Sept.Oct. Fruit per cluster I = weak flowers, low energy reserves II = lack of egg fertilization or tree regulated III = problems with endosperm development IV = problems with embryo development 5 4 3 2 1 0 Other Factors: Water stage fruit split, Mechanical injury, Animals, Insects, Diseases DROUGHT

12. Fruit Sizing Period

13. July Drought Results in Greater Fruit Abortion Sparks, 1989 September drought---leaf abcission/poor kernel filling Nut Sizing

14. Effect of Drought During Nut Sizing A=Irrigated B=Non-irrigated

15. Effect of Drought During Kernel Fill Sparks, 1992

18. What happened to pecan quality in 2011? From Aug-1To Oct-31Total Precipitation [in] Number of Rainy Days 2011 12.3422 2010 6.1222 2009 12.7335 2008 18.8930 1961199010.00N/A 1971200010.12N/A Tifton From Aug-1To Oct-31Total Precipitation [in] Number of Rainy Days 2011 5.6521 2010 11.2322 2009 20.6941 2008 9.9524 1961199010.02N/A 1971200010.41N/A Jeffersonville

19. Pecan Water Stress is a function of water + soil depth

21. Soil Depth & Water 9000 gallons 800 gallons 7 ft topsoil 45 day supply 7 in. topsoil 4 day supply TOPSOIL SUBSOIL

22. How do we manage pecans under drought conditions? IRRIGATE THE ORCHARD!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!! !!!!!

23. How do we manage pecans under drought conditions? Irrigate the orchard Fruit Thin Don’t over-water early in the season

24. How will the 2011 Drought Affect the 2012 Pecan Crop?

25. Data from 1980-2011 r 2 =-0.43 Extreme Drought = -2.75

26. Effect of Rainfall on Pecan Production Sparks, 1996