Acid Sulfate Soil Testing

Visual Test for Acid Sulfate Soil

• If soil has a pale yellow mottling, with coatings of jarosite -- a mineral characterized by amber-yellow to brown crusts or coatings of minute crystals -- it will be acid sulfate type. Acid sulfate soil requires the presence of iron-rich sediments, usually found in seawater. It may be that changes in the water table have resulted in the soil's reclamation.

Laboratory Tests for Acid Sulfate Soil

• Take about 12 core samples of soil at a 6-inch depth from the area to be tested. Mix the cores in a bucket and send about 1 pint of soil to the laboratory for testing. The laboratory will conduct chemical tests to validate the amount of sulfate in the soil. These tests will involve the extraction and measurement of acid sulfate via turbidimetry, atomic absorption spectrophotometry, inductively coupled plasma spectroscopy, potentiometry or high-performance liquid chromatography.

Acid Sulfate Soil is Toxic

• Acid sulfate soil is toxic and, unless it is adjusted, will be unsuitable for growing most plants. It could also damage concrete and metals. Applying lime to acid sulfate soil is not enough to adjust the pH levels, and laboratory testing will be required to work out the exact amounts and types of additions needed to adjust the soil.

Planting for Acid Sulfate Soil

• If your soil is an acid sulfate type, you could consider planting trees. Trees naturally reduce pH levels of soil to around 4.5, so they grow better in acid soils. Choose the variety of tree best suited to your particular hardiness planting zones.