When soil is disturbed by natural weather events or human activities, sulfide-containing matter transforms gardens and other planting areas through chemical reactions into what is known as acid sulfate soils. The transition from neutral, balanced pH soil into a highly acidic one interferes with plants' ability to absorb nutrients and water. Alkaline soil treatments can improve this imbalance and help bring the environment back to a neutral zone.
It is important to test the soil before trying to support any level of vegetation. Plants in an acidic soil environment will be unable to absorb nutrients and suffer from the fatal effects of nutrient deficiency. Testing supplies can be procured from the majority of gardening centers or local testing agencies. This is the first step in treating acidic sulfate soils.
Types of Tests
There are a couple of different methods of testing and reducing high levels of acid in the soil. The suspension peroxide oxidation combined acidity, or SPOCAS, test will offer results identifying the soil as either high, medium, or low acidity or alkalinity. Its results are highly accurate and offer results with an exchange value of how much organic matter is required to fix such problems.
The reducible sulfur method is a similar test that offers the same information but through a different means. These tests are used by scientists in Australia to test their soils.
Patented Peroxide Acidity Test
The patented peroxide acidity test was developed at Virginia Tech and helps scientists by providing descriptive information to accurately prescribe solutions for the environment. It is more accurate than other tests by measuring both the amount of sulfates in the soil and their reactions taking place beneath the soil.
The main method of treating acid sulfate soils is to apply lime, also known as calcium carbonate, to bring back its neutral pH. This is a permanent solution that should not need repeating once the pH has been reset. Packaging instructions will help gardeners calculate the appropriate amounts to apply to the environment. Misuse can lead to further worsening soil for future vegetation.
Failing to test the environment accurately can lead to over-liming the soil and heightening the alkalinity. This type of imbalance is equally deadly to vegetation and will cause future nutrient deficiencies for plants. Spending the extra time and money to properly test the soil can save spending even more down the road.