Louisiana Horticulture Practice Test

When the soil pH drops below 5.5, many nutrients undergo chemical changes that lead to their unavailability to plants. At this lower pH, certain nutrients, particularly essential ones like phosphorus, are less soluble and tend to form compounds that plants cannot absorb. This reduced availability results from increased acidity, which affects the soil's cation exchange capacity and the mineral solubility.

Additionally, essential nutrients such as calcium, magnesium, and potassium may also become less available as the pH decreases. As a consequence, plants may exhibit deficiencies in these nutrients, leading to poor growth and other physiological issues. Thus, understanding the relationship between soil pH and nutrient availability is crucial for effective soil management and ensuring optimum plant health.