Soil pH affects nutrient availability by influencing what two factors?

• A. Color of soil
• B. Nutrient solubility and ion exchange, altering availability to roots
• C. Soil texture
• D. Temperature

Answer: (B)

Soil pH affects nutrient availability by changing how nutrients dissolve in the soil solution and how they are held on soil particles. When pH shifts, some nutrients become more soluble while others become less soluble, so their concentrations in the soil solution—and thus their uptake by roots—change. At the same time, pH alters the charge properties of soil clays and organic matter, which controls cation exchange—how readily nutrients bound to particles can be released into the soil solution for roots to take up. Because availability depends on both how much nutrient is in solution and how easily it can be exchanged from the soil, these two factors—nutrient solubility and ion exchange—best explain how pH governs nutrient availability.