Sulfuric Acid Treatment of Calcareous Soils: Effects on Phosphorus Solubility, Inorganic Phosphorus Forms, and Plant Growth1
- John Ryan and
- Jack L. Stroehlein2
The purpose of this study was to examine the effects of acid (H2SO4) application on three P-deficient calcareous Arizona soils. The acid was mixed with the soils in order to reduce their respective buffering capacities, as measured by the acid titratable basicity (ATB), by 20, 40, 60, 80, and 100%. Two soils, Cave and Comoro, were cropped with tomatoes (Lycopersicum esculentum) after treatment. Significant responses in dry matter yield and P uptake persisted through three successive growth periods. Treatment significantly increased water-soluble P and P-supplying-capacity of the soils. Increasing the H2SO4 rate reduced the H2SO4-P fraction, increased NH4Cl-P and NH4F-P, and to a lesser extent NaOH-P but had little effect on reductant soluble-P. Both extractable Al and Fe increased with increasing amounts of H2SO4 applied. Though difficulties may be encountered in field application, these results show that H2SO4, a waste product mainly from the copper smelting industry, has potential for improving P-deficient calcareous soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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