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

Proven Effects of Gypsum on Soils

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

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

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

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

Southern Company Gypsum Agricultural Demonstration Sites

Gypsum Stack at Plant Yates

Gypsum Stockpile at Yates

Gypsum Loading

Gypsum Spreading at East Lake GC

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

Peanuts

Effect of Gypsum on Soil Tests, Peanut Yield, Quality & Value - Florida Gypsum T/acre Yield lb/acre 3,280 3,940 SMK % 75 Seed Ca % Value $/acre NaNO 3 Ca lb/acre DA Ca lb/acre

Effect of Gypsum on Soil Tests, Peanut Yield, Quality & Value - Mississippi Gypsum T/acre Yield lb/acre 2,936 3,267 1,738 1,939 4,138 4,558 SMK % Seed Ca % Value $/acre NaNO 3 Ca lb/acre DA Ca lb/acre 1,060 1, ,040 1,222 1,600 Field Mid House Barn

Effect of Gypsum on Soil Tests, Peanut Yield, Quality & Value - Georgia Gypsum T/acre Yield lb/acre , ,468 1,406 SMK % Seed Ca % Value $/acre NaNO 3 Ca lb/acre DA Ca lb/acre Var GG C99

Effect of Gypsum on Peanut Yield, Quality & Value - Alabama Gypsum T/acre Yield lb/acre 3,860 4,780 4,340 6,040 SMK % Variety C99R GAGR Value $ ,110.44

Overall Response of Peanuts to Gypsum

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

Alfalfa

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

Control Gypsum Treatment Effect of Gypsum on Exchangeable Al

Effect of Gypsum on Exchangeable Ca Control Gypsum Treatment

Effect of Gypsum on Alfalfa Yield & Composition - Georgia Hay Yield T/ha 0.60 ± ± 0.14* N%N% P%P% K%K% Ca % Mg % Treatment Control Gypsum * significant at P = 0.05

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

Alfalfa Feed Quality - Georgia Parameter Crude protein (%) Crude fiber (%) Neutral detergent fiber (%) Acid detergent fiber (%) Lignin (%) Total digestible nutrients (%) Control Gypsum

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

Cotton

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

Effect of Gypsum on Cotton Yield & Quality - Mississippi Seed Cotton lb/acre 1,661 1,993 Lint Quality Gypsum Treatment T/acre 0 4.4

Effect of Gypsum on Cotton Yield & Value - Georgia Lint Cotton Yield (kg/ha) Treatment Control Gypsum Difference Value Cumulative Profit $ , $ $ , $ $ $55.00 $ $ $598.60

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

Pastures

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

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

Bermuda Root Comparisons

Tomatoes

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 Skin Ca % Effect of Gypsum on Soil Tests, Tomato Yield & Value - Mississippi

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

Effect of Gypsum on Tomato Yield & Ca Content - Alabama July 2005 August 2005Gypsum Treatment T/acre Yield lb/10 ft row Skin Ca %

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

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

Cantaloupes

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

Effect of Gypsum on Soil Tests, Cantaloupe Yield & Ca Content - Georgia Gypsum T/acre Yield lb/plot 221.3a 335.7b 326.7b 322.1b Wt/fruit lb Skin Ca % NaNO 3 Ca mg/L DA Ca lb/acre 989 1,053 1,307 1,651

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

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

Sweetcorn

No gypsum Gypsum

Results Visual improvement due to gypsum Drought killed crop before harvest