Soil Salinity: Issues and Treatment Advanced Soils Topics for Master Gardeners Amy Shober UF/IFAS Gulf Coast REC 1 of 10 ©2008 University of Florida-IFAS

2 of 10 ©2008 University of Florida-IFAS Photo Credit: Geoff Denny, UF-IFAS Sources of Soil Salinity Salt sprays in coastal areas Salty irrigation water –Ground water with salt water intrusion –Reclaimed Water Excessive fertilizer applications

Soil Salinity Issues Mg or K deficiency Destroy soil structure Plant wilt Leaf burn/Necrosis 3 of 10 ©2008 University of Florida-IFAS Photo Credits: Amy Shober, UF-IFAS

What is a Salt? Chemical species Made up of a cation and an anion Held together by an ionic bond Na + Cl - CationAnionSalt 4 of 10 ©2008 University of Florida-IFAS Animation Credits: Amy Shober, UF-IFAS

Materials that Form Salts Cations Sodium (Na + ) Calcium (Ca 2+ ) Potassium (K + ) Ammonium (NH 4 + ) Iron (Fe 2+, Fe 3+ ) Magnesium (Mg 2+ ) Anions Chloride (Cl - ) Sulfate (SO 4 - ) Nitrate (NO 3 - ) Phosphate (PO 4 - ) Acetate (CH 3 COO - ) Hydroxide (OH - ) Carbonate (CO 3 - ) 5 of 10 ©2008 University of Florida-IFAS

Test electrical conductivity (EC) –EC is a measure of the ability of a solution to conduct electricity –As salts in water increase, the EC increases –EC indicates the relative salt level, but not which salts are there Diagnosing a Salinity Problem 6 of 10 ©2008 University of Florida-IFAS

Diagnosing a Salinity Problem Plant ToleranceElectrical ConductivitySalinity dS/m or mmho/cmmg/L or ppm Sensitive<3<2100 Moderately Sensitive – 4200 Moderately Tolerant – 5600 Tolerant – 7000 Highly Tolerant>10> of 10 ©2008 University of Florida-IFAS

Plant Tolerance to Salinity PlantEC Limit (ppm) Hibiscus125 Pittosporum125 Bottlebrush188 Oleander250 Bermudagrass866 Bougainvillea1063 Seashore paspalumVery High 8 of 10 ©2008 University of Florida-IFAS

Dealing with Salt-Affected Soils Leach salts with water –Rain –Irrigation Choose salt- tolerant plants 9 of 10 ©2008 University of Florida – IFAS Photo Credits: Carsten Niehaus

Summary Salinity can be an issue in coastal areas or when irrigation water has high salinity. Excess salts in the soil can lead to plant wilt or nutrient toxicities. Soils and irrigation water can be tested for electrical conductivity (EC) to determine salinity issues. 10 of 10 ©2008 University of Florida-IFAS