Acidic Soil Preferences: Identifying Plants That Thrive in Low pH Environments
Soil acidity is a potential land degradation issue that can significantly affect the growth of plants. This condition, characterised by a low pH level, can lead to nutrient deficiencies and a hostile environment for beneficial soil organisms.
Heavy rainfall can exacerbate soil acidification by causing leaching, the removal of beneficial elements such as calcium and magnesium from the soil. This, in turn, lowers the soil pH, making it more acidic.
One way to address soil acidity is through the use of lime, which raises the pH of acidic soil, making nutrients more available to plants. This was confirmed in a 2012 trial by the Department of Primary Industries and Regional Development, which found that applying lime increased plant uptake of phosphorus, indicating that soil acidity reduces phosphorus availability even when it is present in the soil.
However, it's important to note that some plants thrive in acidic soil environments. Examples include Salbei-Gamander (Teucrium scorodonia), certain Hawkweeds (Hieracium), Deschampsia flexuosa grass, Gardenias, Rhododendrons, Azaleas, Hortensias, Kamelias, and blueberries, among others adapted to low pH environments between 5.0 and 6.0.
On the other hand, agricultural practices such as the removal of plant and animal products, the addition of certain nitrogen-based fertilizers, and the build-up of plant-based organic matter can accelerate the natural process of soil acidification. Chemical fertilizers, particularly high-nitrogen and ammonium-based fertilizers, contribute to soil acidification by releasing hydrogen ions when nitrate is not taken up by plants, increasing soil acidity.
In very acidic soils, major plant nutrients such as nitrogen, phosphorus, potassium, sulphur, calcium, manganese, and molybdenum may be unavailable or present in insufficient quantities. This can lead to poor development and fruiting in plants.
Soil biota, including soil microflora, soil animals, and beneficial organisms like bacteria and earthworms, are sensitive to soil pH. High acidity can degrade the favourable environment for these organisms, affecting the overall health of the soil.
To maintain a balanced soil pH, a soil test is the definitive way to know the quality of the soil, including its pH and nutritional composition. It will offer recommendations on what amendments to use and in what quantities to correct any deficiencies. Adding organic matter, such as compost or peat moss, can also help adjust the soil's pH and improve its ability to hold moisture and air, allowing roots to absorb them.
The pH of the soil can be adjusted by adding lime to raise the pH or sulfur to lower it, but this should be done in stages to avoid shocking plants. It's also crucial to remember that the optimal pH range for most plants is between 5.5 and 7.5.
In conclusion, soil acidity is a crucial factor in plant growth and soil health. By understanding its causes and effects, and by taking appropriate measures to manage it, farmers and gardeners can ensure the optimal growth of their crops and plants.
