Soil pH Amendment for Calcareous Everglades Agricultural Soils.

In the Everglades Agricultural Area, increasing soil pH resulting from Histosol oxidation has increased P and micronutrient retention and decreased its availability to crops.  Use of amendments to reduce soil pH is receiving increasing attention.  Three amendments (ferrous sulfate, aluminum sulfate, and elemental S) applied at various rates and using different application methods were evaluated for their influence on crop yield and nutrient availability.  All amendments increased P and micronutrient availability in the short-term, but long-term effects throughout the growing season were diminished.  These results suggest that the buffering capacity of these calcareous Histosols was substantial.  Optimal amendment rates were about 575 kg/ha, with all amendments producing a similar crop response. Banded application of amendments resulted in higher yields than broadcast at low amendment application rates, but broadcast was better at the higher application rates. Banded application at high rates resulted in harmful effects on lettuce growth, including some burn that limited growth resulting in lower yield compared to broadcasting.