1. Use of Gypsum for Crop Production on Southeastern Soils Malcolm E. Sumner Consultant Lamar Larrimore Principal Research Engineer Southern Company Services, Inc September 12, 2006

2. Proven Effects of Gypsum on Soils

3.  Ca for pod development must enter pod directly Available Calcium for Peanuts Increases: Available calcium (soluble) Peanut pod calcium

4. Al 3+ Al 3+ Al 3+ Al 3+ Al3 + Al 3+ Al 3+ Al 3+ Gypsum Application Al 3+ Al 3+ Al 3+ Ca 2+ Ca 2+ Ca 2+ Crop Reduction of Subsoil Acidity Increases subsoil calcium Reduces subsoil aluminum (toxic) Allows roots to penetrate subsoils Increases potentially available water

5. Control Gypsum Treatment Effect of Gypsum Addition on Root Growth at East Lake Golf Club Gypsum treatment = 4 tons/acre, April 11, 2005 Samples collected May 19, 2006

6. Southeastern Soils Naturally acidic Low basic cation (Ca, Mg, K) status Very acid subsoils often with toxic levels of Al 3+ Sandy to clay loams in texture

7. Southern Company Gypsum Agricultural Demonstration Sites

8. Gypsum Stack at Plant Yates

9. Gypsum Stockpile at Yates

10. Gypsum Loading

11. Gypsum Spreading at East Lake GC

12. Crops Investigated Peanuts Alfalfa Cotton Pastures and Turf Tomatoes Cantaloupes Sweet corn

13. Peanuts

14. Effect of Gypsum on Soil Tests, Peanut Yield, Quality & Value - Florida Gypsum T/acre 0 0.5 Yield lb/acre 3,280 3,940 SMK % 75 Seed Ca % 0.021 0.034 Value $/acre 540.31 649.03 NaNO 3 Ca lb/acre 12 35 DA Ca lb/acre 560 780

15. Effect of Gypsum on Soil Tests, Peanut Yield, Quality & Value - Mississippi Gypsum T/acre 0 0.5 0 0.5 0 0.5 Yield lb/acre 2,936 3,267 1,738 1,939 4,138 4,558 SMK % 77 80 78 Seed Ca % 0.028 0.031 0.026 0.031 0.028 0.035 Value $/acre 498.09 575.76 298.67 333.21 711.09 783.27 NaNO 3 Ca lb/acre 25 69 18 21 51 83 DA Ca lb/acre 1,060 1,683 850 2,040 1,222 1,600 Field Mid House Barn

16. Effect of Gypsum on Soil Tests, Peanut Yield, Quality & Value - Georgia Gypsum T/acre 012012012012 Yield lb/acre 747 943 1,182 879 1,468 1,406 SMK % 72 74 75 65 72 73 Seed Ca % 0.008 0.015 0.019 0.008 0.013 0.019 Value $/acre 109.91 149.40 182.30 114.77 221.54 214.40 NaNO 3 Ca lb/acre 7 33 53 8 55 52 DA Ca lb/acre 232 510 730 389 714 773 Var GG C99

17. Effect of Gypsum on Peanut Yield, Quality & Value - Alabama Gypsum T/acre 0 0.5 0 0.5 Yield lb/acre 3,860 4,780 4,340 6,040 SMK % 67 65 Variety C99R GAGR Value $ 709.65 878.79 797.90 1,110.44

18. Overall Response of Peanuts to Gypsum

19. Results Gypsum –Increases soil calcium –Increases peanut yield –Increases peanut quality –Increases profits

20. Alfalfa

21. Effect of Gypsum on Exchangeable Al and Ca in the Soil Profile

22. Control Gypsum Treatment Effect of Gypsum on Exchangeable Al

23. Effect of Gypsum on Exchangeable Ca Control Gypsum Treatment

24. Effect of Gypsum on Alfalfa Yield & Composition - Georgia Hay Yield T/ha 0.60 ± 0.08 0.95 ± 0.14* N%N% 2.88 3.81 P%P% 0.22 0.27 K%K% 2.80 3.20 Ca % 0.73 1.20 Mg % 0.27 0.20 Treatment Control Gypsum * significant at P = 0.05

25. Effect of Gypsum on Soil Moisture - Georgia Control Gypsum Treatment Gypsum extracted more water at depth

26. Alfalfa Feed Quality - Georgia Parameter Crude protein (%) Crude fiber (%) Neutral detergent fiber (%) Acid detergent fiber (%) Lignin (%) Total digestible nutrients (%) Control 18.0 22.6 37.5 28.1 7.6 66.2 Gypsum 23.8 19.4 31.7 24.7 5.8 71.9

27. Results Gypsum –Increases calcium in soil profile –Reduces toxic aluminum in soil profile –Improves water extraction from lower profile –Increases alfalfa yield –Increases alfalfa quality Higher protein & digestible nutrients Less fiber and lignin

28. Cotton

29. Contorted tap roots due to Al toxicity Straight tap roots in absence of Al Effect of Gypsum on Cotton Root Development - Mississippi

30. Effect of Gypsum on Cotton Yield & Quality - Mississippi Seed Cotton lb/acre 1,661 1,993 Lint 612 729 Quality 303 336 Gypsum Treatment T/acre 0 4.4

31. Effect of Gypsum on Cotton Yield & Value - Georgia Lint Cotton Yield (kg/ha) Treatment Control Gypsum Difference Value Cumulative Profit 2000 347 346 0 -$125.00 2001 862 1,107 245 $269.50 $144.50 2002 999 1,251 251 $276.10 $420.60 2003 380 430 50 $55.00 $465.60 2004 745 867 122 $133.00 $598.60

32. Results Gypsum –Reduces subsoil Al and increases subsoil Ca –Improves root penetration into subsoil –Increases cotton yield –Increases cotton quality

33. Pastures

34. Effect of Gypsum on Bermuda Hay Yield & Ca Content - Georgia Treatment Control 4.4 T/acre Hay Yield lb/acre May 2005 1136a 1549b Sept 2005 402a 737b Sept 2005 0.6a 0.75b Ca Content % Gypsum

35. Effect of Gypsum on Bermuda Root Growth - Georgia Control Gypsum Treatment

36. Bermuda Root Comparisons

37. Tomatoes

38. Gypsum T/acre 0202 Yield lb/acre 14,782 17,695 DA Ca lb/acre 1,315 1,659 Value $ 5,896 7,072 NaNO 3 Ca mg/kg 20 48 Skin Ca % 0.46 0.83 Effect of Gypsum on Soil Tests, Tomato Yield & Value - Mississippi

39. Effect of Gypsum on Shelf Life of Tomatoes (Stored at Room Temperature for 2 Weeks - Mississippi)

40. Effect of Gypsum on Tomato Yield & Ca Content - Alabama July 2005 August 2005Gypsum Treatment T/acre 0202 0202 Yield lb/10 ft row 40 48 28 34 0.46 0.67 Skin Ca % 0.56 0.71

41. Control Gypsum Effect of Gypsum on Shelf Life of Tomatoes Blemishes on fruit after 4 weeks storage @ 40°F Unblemished fruit after 4 weeks storage @ 40°F

42. Results Gypsum –Increases tomato yield –Increases skin Ca content –Increases shelf life

43. Cantaloupes

44. No Gypsum0.5 T Gypsum/ac 1 T Gypsum/ac1.5 T Gypsum/ac

45. Effect of Gypsum on Soil Tests, Cantaloupe Yield & Ca Content - Georgia Gypsum T/acre 0 0.5 1.0 1.5 Yield lb/plot 221.3a 335.7b 326.7b 322.1b Wt/fruit lb 4.66 4.71 4.97 5.17 Skin Ca % 1.07 1.24 1.34 1.44 NaNO 3 Ca mg/L 14 22 41 56 DA Ca lb/acre 989 1,053 1,307 1,651

46. Cantaloupes stored at 40 ° F for 4 weeks No Gypsum 1100 lb Gypsum/ac

47. Results Gypsum –Increases cantaloupe vine growth –Increases fruit yield –Increases skin Ca content –Increases shelf life

48. Sweetcorn

49. No gypsum Gypsum

50. Results Visual improvement due to gypsum Drought killed crop before harvest