The Impact of Organic Acids on Soil Health and Acidification
Posted August 2025
Researchers: Davie Kadyampakeni, Tripti Vashisth
Contact: Davie Kadyampakeni, UF/IFAS CREC dkadyampakeni@ufl.edu
Summary:
We conducted an experiment for 4.5 years to determine the effects of soil amendments on soil pH. We compared the impacts of fulvic acid, humic acid, and sulfuric acid with and without elemental sulfur. We tracked and analyzed canopy size, fruit yield, fruit quality, soil nutrient availability, leaf nutrient levels, and root density in the field. Moderate acidity (5.5- 6.5) promoted nutrient availability compared to pH greater than 7.5. There was a positive correlation between soil pH and soil calcium (Ca), magnesium (Mg), zinc (Zn), manganese (Mn), and boron (B), possibly suggesting that the availability of these soil nutrients increased as pH increased. A negative correlation was observed between soil pH and soil iron (Fe), sulfur (S), potassium (K), and phosphorus (P), indicating decreased nutrients in soil solution as pH increased. Fulvic acid + elemental sulfur had increased the root density, while humic acid + elemental S showed a significantly lower root density. Use of organic acids such as humic acid and fulvic acid should be considered for lowering soil pH along with elemental sulfur. Combined use of organic acids and elemental sulfur increased nutrient availability on Florida sandy soils, though fruit yields and fruit quality were comparable between treatments over the four years.
Take Home Message:
- Fulvic acid + elemental sulfur had increased the root density, while humic acid + elemental S showed a significantly lower root density.
- A negative correlation was observed between soil pH and soil iron (Fe), sulfur (S), potassium (K), and phosphorus (P), indicating decreased nutrients in soil solution as pH increased.
- Use of organic acids such as humic acid and fulvic acid should be considered for lowering soil pH along with elemental sulfur.
