Why Trees Need the Right Soil pH

Created By RISC | 1 week ago

Last modified date : 1 week ago

Soil isn’t just a solid foundation for trees but a source of essential nutrients that can help them thrive.

Trees need 14 types of nutrients for growth:

6 macronutrients: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). These are essential for growth and are required in large amounts. A deficiency can stunt growth and cause the plant to wilt or even die.

8 micronutrients: iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), nickel (Ni), and chlorine (Cl). Although required in smaller quantities, these nutrients are just as vital for plant health.

Soil typically has these nutrients but how well plants can absorb them depends on the soil’s pH level, which affects their solubility in a form that plants can absorb.

The optimal pH for soil is about 6.0 to 6.5. If the pH is too high or too low, some nutrients become less soluble and unavailable for plants. With a pH below 6, phosphorus becomes less soluble. Highly acidic soil can reduce yields and cause short and swollen roots with damaged tips.

We can fix these problems. With acidic soils, use lime-containing materials such as wood ash, crushed limestone, quicklime, or dolomite. With alkaline soils, apply aluminum sulfate or sulfur.

Story by: Nakarin Phongphaew, Intern from Department of Botany, Faculty of Science, Chulalongkorn University and Thanawat Jinjarak, senior researcher Environmental Department Urban Environmental & Biodiversity Engineer, RISC